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Zoological Journal of the Linnean Society, 2014, 170, 710–734. With 9 figures
Modern hydrophilid clades present and widespread
in the Late Jurassic and Early Cretaceous
(Coleoptera: Hydrophiloidea: Hydrophilidae)
MARTIN FIKÁČEK1,2*, ALEXANDER PROKIN3,4, EVGENY YAN5,6, YANLI YUE5,7,
BO WANG5,8, DONG REN9 and ROBERT BEATTIE10
1
Department of Entomology, National Museum, Kunratice 1, CZ-14800 Praha 4-Kunratice, Czech
Republic
2
Department of Zoology, Faculty of Science, Charles University in Prague, Viničná 7, CZ-12843
Praha 2, Czech Republic
3
Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Nekouzsky
District, 152742 Yaroslavl Oblast, Russia
4
Venevitinovo Research and Educational Centre, Voronezh State University, Universitetskaya pl. 1,
394006 Voronezh, Russia
5
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and
Palaeontology, Chinese Academy of Sciences, 39 East Beijing Rd, Nanjing 210008, China
6
Paleontological Institute, Russian Academy of Sciences, 123 Profsoyuznaya Str., Moscow 117647,
Russia
7
School of Life Science, Ningxia University, Ningxia, China
8
Steinmann Institute, University of Bonn, 53115 Bonn, Germany
9
College of Life Sciences, Capital Normal University, Beijing 100048, China
10
119A Merrigang St., Bowral, New South Wales 2576, Australia
Received 10 August 2013; revised 31 October 2013; accepted for publication 12 November 2013
We present a summary of the fossil evidence documenting the worldwide occurrence of the family Hydrophilidae
(Insecta: Coleoptera: Polyphaga: Hydrophiloidea) in the Late Jurassic and Early Cretaceous. We present the first
known fossils of the family from the Mesozoic, being c. 100 Myr older than the fossil record available until now.
Two Late Jurassic fossils are documented: Protochares brevipalpis gen. nov., sp. nov. from the Talbragar Fish
Bed (New South Wales, Australia) and ‘Mesosperchus’ schultzi Ponomarenko, 1985 from Solnhofen (Bavaria,
Germany). The occurrence of the Hydrophilidae in the Early Cretaceous is documented by six species, all of which
may be already assigned to modern subfamilies/tribes: Baissalarva hydrobioides gen. nov., sp. nov. from the
Baissa outcrops (Buryat Republic, Russia) and Cretoxenus australis gen. nov., sp. nov. from Koonwarra
outcrops (Victoria, Australia) are both assigned to the tribe Hydrobiusini (Hydrophilinae); Alegorius yixianus
gen. nov., sp. nov. and Alegorius sp. from the Yixian Formation (Liaoning, China) may represent the Acidocerinae
or Enochrinae, Hydroyixia elongata gen. nov., sp. nov. and H. latissima sp. nov. from the same locality are
assigned to the Acidocerinae. The phylogenetic position of Baissalarva hydrobioides is also tested by a phylogenetic
analysis. The presence of extant clades (Hydrophilinae: Hydrobiusini, Acidocerinae) in the Early Cretaceous and
the wide distribution of the Hydrobiusini in both Gondwana and Laurasia at the same time suggests that the
principal extant clades of the Hydrophilidae are at least of Early–Middle Jurassic origin.
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734.
doi: 10.1111/zoj.12114
ADDITIONAL KEYWORDS: Acidocerinae – fossil record – Hydrobiusini – Hydrophilinae – Mesozoic – new
taxa.
*Corresponding author. E-mail: [email protected]
710
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
MODERN HYDROPHILID CLADES IN THE MESOZOIC
INTRODUCTION
With 2900 extant species, water scavenger beetles
(family Hydrophilidae) currently represent the largest
lineage of the superfamily Hydrophiloidea; the remaining five hydrophiloid families (Helophoridae, Georissidae, Epimetopidae, Hydrochidae, and Spercheidae)
are rather species-poor and together contain no more
than 400 described species (Short & Fikáček, 2011).
The family Hydrophilidae is particularly well known
due to its aquatic species inhabiting a wide spectrum of
habitats, including the margins of lakes and streams,
open marshes, and seepages and wet rocks. About
one-third of known species are terrestrial, mostly
inhabiting forest leaf litter, mammal excrements, or
other decaying plant matter (Short & Fikáček, 2013).
The monophyly of the family is supported by both
morphological and molecular data (e.g. Hansen, 1991;
Archangelsky, 2004; Bernhard et al., 2006, 2009; Short
& Fikáček, 2013), and its internal classification was
recently revised by Short & Fikáček (2013).
Based on published data, the fossil record of the
Hydrophilidae seems to be rather rich. In total, c. 180
extinct species have been mentioned in the literature
published prior to 2010. These species were accommodated in 55 genera, of which 33 are presumed to be
extinct (M. Fikáček, unpubl. data). Many of these
species were, however, attributed to Hydrophilidae
sensu lato (= Hydrophiloidea sensu stricto in current
classification). An ongoing revision of these fossils
has revealed that many belong to the smaller
hydrophiloid families, others do not belong to the
Hydrophiloidea at all, and the position of some
remain unclear, usually due to the incomplete
preservation of the respective fossil (e.g. Fikáček,
Wedmann & Schmied, 2010a; Fikáček, Schmied &
Prokop, 2010b, Fikáček, Hájek & Schmied, 2011;
Fikáček et al., 2012a; Fikáček & Schmied, 2013).
When all these species with uncertain or ambiguous
status are not considered, the fossil record of the
Hydrophilidae is in fact rather poor and does not date
back further than the Eocene. Moreover, all Tertiary
fossils belong to extant genera and thus already represent the modern fauna (Fikáček, Hájek & Prokop,
2008; Fikáček et al., 2010a; Fikáček, Prokop & Nel,
2010c; Fikáček & Engel, 2011; Fikáček & Schmied,
2013; M. Fikáček & M. S. Engel, unpubl. data).
The early evolution of the Hydrophilidae remained
undocumented in the fossil, even though a Jurassic–
Cretaceous minimum age was expected for the family
based on the fact that other hydrophiloid families
were already well established by the Late Jurassic.
(Fikáček et al., 2012b).
In the present paper we summarize the data on the
Mesozoic fossils that may be positively assigned to the
family Hydrophilidae. All of these fossils except one
711
(‘Mesosperchus’ schultzi Ponomarenko, 1985) were not
previously studied in detail and most came from
recent excavations of deposits in Russia, China, and
Australia. Based on the material accumulated for this
study, we are able to document the occurrence of the
family Hydrophilidae in the Late Jurassic and Early
Cretaceous as well as its wide geographical distribution during the Late Mesozoic.
MATERIAL AND METHODS
FOSSILS
Mesozoic fossils assigned to the Hydrophiloidea by
previous authors as well as those previously unstudied
from Russian, Mongolian, and Chinese deposits were
examined by A.P., E.Y., and M.F. Specimens were
examined either dry or under alcohol to enhance
contrast. Photographs of the fossils were made using a
DXM1200 camera attached to a Nikon SMZ1000 (for
Protochares) and a Leica DFC420 camera attached to
the Leica M165c microscope (for remaining material
examined). Preparation of the only known specimen of
Protochares was done using a PaleoTools Micro-Jack 3.
The depository of the specimens examined is indicated
by the following prefixes of their inventory numbers:
AMF, Department of Earth Sciences, Australian
Museum, Sydney; CNU, Capital Normal University,
Beijing, China; NIGP, Nanjing Institute of Geology and
Paleontology, Chinese Academy of Sciences; NHMW,
Geologisch-Paläontologische Abteilung, Naturhistorisches Museum, Wien, Austria; NMVP, Department of
Paleontology, Museum Victoria, Melbourne, Australia;
PIN, Paleontological Institute of the Russian Academy
of Science, Moscow, Russia.
The main purpose of this contribution is to describe
the hydrophilid fossils to allow their use for further
studies concerning the phylogeny and evolution of the
family. The study is hence focused especially on the
genus level. Differences at the species level are only
briefly discussed in cases where multiple species
of the genus occur in the same outcrop. The only
fossil described earlier and treated in this paper
is rather poorly preserved and we refer to it using
the original name under which it was described,
i.e. ‘Mesosperchus’ schultzi Ponomarenko, 1985. The
quotation marks indicate it does not belong to
Mesosperchus Ponomarenko, 1977 which is now considered a subgenus of Helophorus Fabricius, 1775 (see
Fikáček et al., 2012a).
Classification of the family follows that proposed
recently by Short & Fikáček (2013). Morphological
terminology follows Komarek (2004) and Lawrence
et al. (2010); the term trichobothrium is used for
‘systematic puncture’ sensu Hansen (1991; see
Fikáček et al., 2012b for details).
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
712
M. FIKÁČEK ET AL.
PHYLOGENETIC
ANALYSIS
Most fossils treated in this paper lack enough wellpreserved phylogenetically informative characters
to test their position by a formal phylogenetic analysis.
The only exception is the Cretaceous larva from Baissa
outcrops described below as Baissalarva hydrobioides
gen. nov., sp. nov., which position we therefore tested
by maximum-parsimony analyses. We used the dataset
of Archangelsky (2004) as a basis of the data. Although
this dataset lacks chaetotaxic and some other recently
discovered characters of supposed phylogenetic importance, it remains the most complete larval dataset and
includes most relevant ‘easy-to-observe’ characters
that are preserved in the fossil. We coded 42 of 50
larval characters used by Archangelsky (2004) within
our analysis, four of them in a modified version, plus
seven additional characters observable in the fossil
(i.e. the detailed morphology of the nasale and morphology of the abdomen) (see Tables 3 and 4). We
excluded multiple species of uniformly looking genera
(Berosus Leach, 1817) from the original dataset, but
additionally included genera whose larvae were
described recently or were not included into the original dataset: Guyanobius adocetus Spangler, 1986
(Spangler, 1986; Archangelsky, 1997), Notionotus
liparus Spangler, 1972, Crenitis morata (Horn, 1890),
Hydrobiomorpha casta (Say, 1835) (Archangelsky,
1997), Hemiosus bruchi Knisch, 1924 (Archangelsky,
2000),
Anacaena
suturalis
(LeConte,
1866)
(Archangelsky & Fikáček, 2004), Agraphydrus narusei
(Satô, 1960), Enochrus japonicus (Sharp, 1873),
Hydrobius pauper Sharp, 1884 (see Sharp, 1884a),
Sternolophus rufipes (Fabricius, 1792), Hydrochara
affinis (Sharp, 1873) (Minoshima & Hayashi, 2011a),
Amphiops mater Sharp, 1873 (Minoshima & Hayashi,
2012b), and Tormus helmsi Sharp, 1884 (see Sharp,
1884b) (Fikáček et al., 2013). To cover the larval morphology of all main clades of the Hydrophilidae,
we also included data on the rygmodine genera
Cylomissus Broun, 1903 and Rygmodus White, 1846,
larvae of which are now under description (Minoshima
et al., unpubl. data). For a list of characters and their
states, see Appendix Table 3.
We ran two analyses: (1) an unconstrained analysis
based on morphological data, and (2) a constrained
analysis using the topology revealed by the multigene analysis of Short & Fikáček (2013) as a backbone tree and allowing Baissalarva to sit at any
position of this tree. Both analyses were performed
in TNT software (Goloboff et al., 2008) using the
Traditional Search with 10000 replicates and 100
trees saved per replicate. The constrained analysis
was performed as follows: (1) any tree from the
unconstrained analysis was used as a source; (2)
Baissalarva was pruned from the tree using the
pruntax command; (3) the topology of the tree was
edited in Trees>View mode after unlocking the trees
(Settings>Lock trees) to match the results of the
analysis by Short & Fikáček (2013); (4) the tree was
set up as backbone tree using the command force
(force /&0 in the case the original tree had number 0
in RAM); and (5) the Traditional Search analysis was
repeated with the choice Enforce constraints selected.
Characters were mapped on the resulting trees in
Winclada software (Nixon, 2002).
KNOWN MESOZOIC FOSSILS OF
THE HYDROPHILIDAE
LATE JURASSIC
‘Mesosperchus’ schultzi
Ponomarenko, 1985
Protochares brevipalpis
sp. nov.
Solnhofen (Germany)
Talbragar (Australia)
EARLY CRETACEOUS
Hydrophilinae: Hydrobiusini
Baissalarva hydrobioides
sp. nov.
Cretoxenus australis
sp. nov.
Baissa (eastern Russia)
Koonwarra (Australia)
Acidocerinae:
Hydroyixia elongata sp. nov. Yixian Formation (China)
Hydroyixia latissima sp. nov. Yixian Formation (China)
Acidocerinae or Enochrinae:
Alegorius yixianus sp. nov.
Yixian Formation (China)
TAXONOMY
‘MESOSPERCHUS’ SCHULTZI PONOMARENKO, 1985
Mesosperchus schultzi Ponomarenko, 1985: 142.
‘Mesosperchus’ schultzi: Fikáček et al. (2012a: 123,
excluded from Mesosperchus, assigned to Polyphaga
incertae sedis).
Type locality and age: Germany, Bavaria, Solnhofen.
Solnhofen Formation, Late Jurassic, Lower Tithonian,
150.8–145.5 Mya (Labandeira, 2003).
Material examined: Holotype: 1985/20, piece and
counterpiece, poorly preserved specimen in a whitish
limestone (Fig. 1C–E, G–H).
Redescription: Body widely elongate oval. For body
measurements, see Table 1.
Head slightly wider than long. Clypeus large,
nearly continually arcuate on anterior margin.
Frontoclypeal suture present, well developed, reaching lateral margin of head closely before each eye.
Eyes large, separated by c. 2.4× the width of one eye.
Gula slightly narrowing anteriad, gular sutures
widely separate from each other.
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
MODERN HYDROPHILID CLADES IN THE MESOZOIC
713
Figure 1. Late Jurassic fossils of the Hydrophilidae. Protochares brevipalpis gen. nov., sp. nov., AMF109568,
Talbragar, Australia (A, B, F); ‘Mesosperchus’ schultzi Ponomarenko, 1985, NHMW 1985/20, Solnhofen, Germany: whole
specimen (C, G–H), details of the head of the piece using different lighting (D–E). Abbreviations: aes3, metanepisternum;
fcs, frontoclypeal suture; gs, gular suture; mttr1, metatarsomere 1; mxp, maxillary palpus; prospr, prosternal process;
scstr, scutellar stria; sstr, sutural stria.
Prothorax. Pronotum transverse, narrowing anteriad; anterolateral corners rounded, projecting anteriad. Prosternal process widely triangular. Procoxae
contiguous.
Mesothorax. Scutellar shield small, triangular.
Elytron with sharply but finely impressed striae.
Legs. Metatibia rather long and slender.
Family assignment: Ponomarenko (1985) originally
described this species in the genus Mesosperchus
Ponomarenko, 1977 containing three additional
Late Jurassic species, and assigned it to the
Hydrophilidae sensu lato (which corresponds to the
superfamily Hydrophiloidea in current classification).
Recent revision by Fikáček et al. (2012a) revealed
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
714
M. FIKÁČEK ET AL.
Table 1. Body measurements of the Mesozoic Hydrophilidae preserved as adults (in mm)
TL
Protochares brevipalpis
AMF109568
HT
‘Mesosperchus’ schultzi
NHMW 1985/20
HT
Cretoxenus australis
NMVP 103312
HT
Hydroyixia elongata
CNU 2010005
HT
CNU 2009075
PT
Hydroyixia latissima
CNU 2009074
HT
CNU 2009107
PT
CNU 2010014
PT
Alegorius yixianus
CNU 2009079
HT
CNU 2009078
PT
CNU 2009080
PT
CNU 2009077
PT
CNU 2010024
CNU 2010025
NIGP 156965
Alegorius sp.
CNU 2009081
HW
CW
IOD
PL
PW
EL
EW
MSL
MTL
7.6
1.8
1.3
1.1
1.4
3.7
5.0
2.2
–
–
10.0*
2.2*
1.9
1.1
1.8
4.6
6.3
3.3
–
1.9*
8.0*
1.5
1.2
0.8
1.5
2.7
5.0
1.8
0.9
1.3
8.3*
11.8
1.7*
2.3
1.4
2.0
0.9
1.3
–
1.9
3.2
4.4
5.1
8.0
1.9
3.1
1.0
–
1.1
1.8
10.6
9.8*
12.4*
2.6
–
2.7*
2.0
–
–
1.4
–
1.7*
2.0
1.9
2.1
4.7
4.3
4.6*
7.7
7.4
8.3
3.4
3.1
3.4*
1.4*
1.2
–
1.8
1.8
–
10.6
10.1
11.4
12.2
–
10.4
11.3
2.4
2.3*
2.8*
2.8
2.4
–
2.9
1.8
1.9
2.1*
2.1
1.9
1.6
2.1
1.1
1.1
1.5
–
1.3
–
1.4
1.9*
1.5*
1.8*
2.4
1.6*
1.9
1.9*
4.3
4.0*
4.6
4.5
4.3
4.2*
4.4
6.9*
6.5
7.9
8.5
–
7.0
7.7*
2.8
2.6
3.5
3.3
3.1
3.0
3.1
1.2
1.2
–
–
–
–
–
1.4
1.5
2.2
–
–
–
–
–
–
1.4
1.3
2.8*
4.3
2.0
–
–
6.4
Abbreviations: HT, holotype; PT, paratype; TL, total body length; HW, head width; CW, clypeus width; IOD, interocular
distance; PL, pronotum length; PW, pronotum width; EL, elytron length; EW, elytron width; MSL, length of mesoventrite;
MTL, length of metaventrite. Measurements estimated from incompletely preserved body parts are marked by an
asterisk.
that M. schultzi does not belong to Mesosperchus
Ponomarenko, 1977, which is now considered a
formal subgenus of Helophorus (Hydrophiloidea:
Helophoridae), comprising its Late Jurassic species
(Fikáček et al., 2012a,b). Instead, ‘Mesosperchus’ schultzi was shown to resemble modern
Hydrophilidae by the shape of the head, presence of
the large clypeus and distinct frontoclypeal suture
(Fikáček et al., 2012a). Because of the poor preservation and doubts of the authors about the occurrence of
the family Hydrophilidae in the Jurassic, Fikáček
et al. (2012a) followed a very conservative approach
and rather did not include ‘Mesosperchus’ schultzi
in the family. The discovery of the well-preserved
fossil of Protochares brevipalpis gen. nov., sp. nov.
clearly demonstrates the occurrence of the family
Hydrophilidae in the Late Jurassic, and allows us to
be less conservative and assign ‘Mesosperchus’
schultzi to the Hydrophilidae. Despite this, additional
better-preserved specimens from Solnhofen are necessary to confirm this assignment. Based on this
fossil, we consider the occurrence of the modern
Hydrophilidae in Europe during the Late Jurassic as
highly probable.
PROTOCHARES
GEN. NOV.
Type species: Protochares brevipalpis sp. nov. (by
present designation).
Time range: Late Jurassic.
Diagnosis: Body medium-sized; body elongate oval;
labrum well sclerotized and at least partly exposed;
maxillary palpi rather short and stout; scutellar
shield small, triangular; elytron with ten series;
scutellar stria present; basal metatarsomere 1 much
shorter than metatarsomere 2.
Etymology: The generic name consists of the Latin
prefix proto- meaning ‘early’, and the ending -chares
reflecting the superficial resemblance of the new
genus to the extant genus Helochares. Masculine.
Family assignment: Protochares gen. nov. may be
reliably assigned to the superfamily Hydrophiloidea
by the large clypeus and distinct frontoclypeal
sutures reaching the lateral margin of the head
closely before eyes. The presence of the triangular
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
MODERN HYDROPHILID CLADES IN THE MESOZOIC
scutellar shield excludes all hydrophiloid families
except Hydrophilidae and Spercheidae (Fikáček et al.,
2012b); from Spercheidae it differs in head not
strongly constricted behind the eyes and the wellsclerotized and largely exposed labrum. It may be
therefore reliably assigned to the Hydrophilidae s.s.
Comparison with other hydrophilid genera: Based on
the combination of the first metatarsomere much
shorter than the second and the exposed labrum,
Protochares gen. nov. corresponds well with modern
representatives of the non-sphaeridiine groups of the
Hydrophilidae. Among these, its general habitus and
medium body size resemble, in particular, the extant
representatives of the tribes Hydrobiusini (from most
of which it differs by smaller body size and rather
short maxillary palpi), subfamily Enochrinae (in
contrast to which it bears five segmented metatarsi
and short maxillary palpi), Acidocerinae (from many
of which it differs by short maxillary palpi) and
Rygmodinae (from which it differs by the presence of
the scutellar stria on the elytron). All four extant
groups are characterized by a rather generalized
body and lack of ‘easy-to-see’ synapomorphies (Short
& Fikáček, 2013), which makes the diagnosis of
Protochares gen. nov. rather difficult. Still, the combination of diagnostic characters listed above and the
Jurassic age of the fossil justifies the assignment of
the fossil to a separate genus.
Protochares differs from the Early Cretaceous
hydrophilid genera described below by rather wide
metanepisterna (in contrast to much narrower ones in
Cretoxenus gen. nov.), relatively short maxillary palpi
(in contrast to rather long ones in Cretoxenus gen.
nov. and probably also in Alegorius gen. nov.) and by
a probably not excised clypeus and partly exposed
labrum (in contrast to excised clypeus in all Cretaceous genera and labrum situated in the clypeal excision in Hydroyixia gen. nov., see Fig. 8A, C, E).
715
Head slightly wider than long. Clypeus large,
arcuate on anterolateral margins, with anteromedian
portion straight or weakly concave (poorly preserved).
Frontoclypeal suture present, well developed, reaching lateral margin of head closely before anterior
margin of each eye. Eyes large, slightly protruding
from head outline, separated by c. 3.0× the width of
one eye; postocular bridge absent. Gula slightly
narrowing anteriad, gular sutures widely separate
from each other. Labrum large, transverse, well
sclerotized, slightly concave on anterior margin, at
least partly exposed in front of clypeus. Maxillary
palpi rather short and stout, palpomeres 3 and 4
subequal in length.
Prothorax.
Pronotum
transverse,
narrowing
anteriad; anterolateral corners rounded, slightly projecting anteriad, lateral margins arcuate with narrow
marginal rim; pronotal surface even, without furrows
or depressions.
Mesothorax. Scutellar shield small, triangular.
Elytron with ten slightly impressed punctural series,
punctures rather small and arranged close to each
other. Sutural stria present, deeply impressed.
Scutellar stria present, finely punctate.
Metathorax. Metanepisternum rather wide.
Legs. Tibiae cylindrical, with several series of
spines on dorsal surface. Tarsi with five tarsomeres;
protarsus with long tarsomere 5 bearing short
arcuate claws; metatarsomere 1 short, distinctly
shorter than metatarsomere 2.
Etymology: The species name refers to the relatively
short maxillary palpi.
ALEGORIUS
GEN. NOV.
Type species: Alegorius yixianus sp. nov., by present
designation.
Time range: Early Cretaceous.
PROTOCHARES
BREVIPALPIS SP. NOV.
Hydrophilidae: Beattie & Avery (2012: 7, fig. 6B)
Type locality and age: Australia, New South Wales,
Talbragar Fossil Fish Bed, c. 14 km NNW of Ulan,
25 km NE of Gulgong, 32°9.9′S, 149°41.0′E; Late
Jurassic (Oxfordian–Tithonian, i.e. 161–145 Mya
based on SHRIMP analysis; Kimmeridgian, i.e. 155–
150 Mya based on fish fauna) (Beattie & Avery, 2012).
Material examined: Holotype: AMF109568, piece only,
complete beetle in dorsal view (Fig. 1A, B, F).
Description: Body widely elongate oval; for body
measurements see Table 1.
Diagnosis: Body medium-sized; labrum partly
exposed in dorsal view (Figs 2A–B, 8A); anterior
margin of clypeus weakly excised mesally (Figs 2B,
8A); prosternum moderately long, weakly carinate/
elevated medially (Fig. 2B); scutellar shield small,
triangular; anapleural sutures well developed,
strongly curved, nearly parallel-sided and widely
separate anteriorly (Figs 2A–B, 8B); mesocoxae very
narrowly separated; abdomen with five ventrites;
apical abdominal ventrite with deep and narrow
emargination (Figs 2A, 7C); elytron with deeply
impressed sutural stria; elytra with series of punctures (Fig. 2A); tarsi of mesothoracic leg with five
tarsomeres; mesotarsomere 1 very short (Fig. 2B).
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
716
M. FIKÁČEK ET AL.
Figure 2. Alegorius yixianus gen. nov., sp. nov. from the Yixian Formation, China. Holotype, CNU 2009079 (A);
paratype, CNU 2009078 (B). Abbreviations: abem, apical emargination of abdominal ventrite 5; aes3, metanepisternum;
bst, maxillary basistipes; fmtta, free metatibial anterobasal angle; lb, labrum; men, mentum; mstr1, mesotarsomere 1;
msv, mesoventrite; pros, prosternum; sstr, sutural stria; tf, transverse fold of prothorax.
Etymology: Alegorius is an arbitrary combination
of letters inspired and loosely derived from the
given and patronymic names Alexander Georgievich,
referring to three Russian specialists on fossil and
aquatic beetles, Alexander Georgievich Ponomarenko,
Alexander Georgievich Kirejtshuk and Alexander
Georgievich Shatrovskiy, who supported the authors
of this paper in their palaeontological and taxonomic
studies. Masculine.
Family assignment: The combination of large clypeus,
well-developed frontoclypeal sutures reaching lateral
margin of head closely before eyes, head not constricted behind eyes, small triangular scutellar shield
and femora with anteromesal corner not facing trochanter (Fig. 9, fmtta) assign the fossil reliably to the
family Hydrophilidae s.s. Additionally, it corresponds
well with the modern Hydrophilidae in the general
habitus and ventral morphology.
Comparison with other genera: Based on the presence
of the apical emargination on the posterior margin
of the abdominal ventrite 5, Alegorius resembles the
extant representatives of the Hydrobiusini and early
branching Hydrophilini, and those of the subfamilies
Enochrinae and Acidocerinae. In contrast to the
Hydrobiusini and Hydrophilini, the mesoventrite of
Alegorius is wide anteriorly and does not bear a
common ventral keel; in contrast to the Cymbiodyta
group of the Enochrinae, the mesothoracic leg bears
five tarsomeres. Hence, it seems that Alegorius may
be assigned either to the Enochrus-group of the
Enochrinae or to the subfamily Acidocerinae. It corresponds with extant species of both clades in general
body shape, presence of the shallow anterior excision
of the clypeus, and the presence of sharply impressed
sutural stria. A more detailed comparison with extant
genera is not possible because relevant characters are
not preserved in the examined fossils.
Alegorius gen. nov. differs from other Cretaceous
fossil genera of the Hydrophilidae especially by the
strongly curved anapleural sutures that are nearly
parallel and widely separated anteriorly (in contrast
to straight anapleural sutures of Cretoxenus gen.
nov. and anteriorly joining anapleural sutures
of Hydroyixia gen. nov., compare Figs. 8B, D, F).
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MODERN HYDROPHILID CLADES IN THE MESOZOIC
Detailed comparison with Jurassic fossils described above is not possible due to their incomplete
preservation.
ALEGORIUS
YIXIANUS SP. NOV.
Type locality and age: China, Liaoning Province,
Shangyuan County, Chaomidian Village, Huangbanjigou, Yixian Formation, Early Cretaceous, Lower Cretaceous, Aptian, 124.6 Mya (Swisher, Wang & Wang,
1999). An alternative dating was proposed by Zheng,
Zheng & Xing (2003): Jurassic–Cretaceous boundary,
Late Tithonian–Berriasian, c. 145–140 Mya. See Ren
et al. (2010) for discussion on various datings of the
formation.
Material examined (seven specimens): Holotype: CNU
2009079, piece only (Figs 2A, 7A–C). Paratypes: CNU
2009078, piece only (Figs 2B, 7D–E); CNU 2009077,
piece only; CNU 2009080, piece only. Additional specimens examined: CNU 2010024, piece only; CNU
2010025, piece only (all CNU specimens from the type
locality); NIGP 156965, piece only [specimen from the
Lower Cretaceous Yixian Formation of Liutiaogou,
Yangshuwanzi Village, Ningcheng County, Chifeng
City, Inner Mongolia, China; see Wang et al. (2012)
details of the locality].
Description: Body elongate oval; for body measurements see Table 1.
Head c. as long as wide. Clypeus slightly explanate
laterally, shallowly concave on anterior margin;
lateral portions appear paler than central portion.
Eyes moderately large, oval, divided by c. 1.8–
2.3× the width of one eye; postocular bridge not
developed. Gula slightly narrowing anteriad, weakly
carinate medially in posterior portion; gular sutures
widely separate from each other. Labrum transverse,
partly exposed anterior to clypeus, straight to slightly
convex on anterior margin. Maxillary basistipes
subtriangular, maxillary palpi probably rather long
(CNU 2009078, Fig. 2A). Mentum subrectangular, c.
1.5× wider than long.
Prothorax. Pronotum transverse, slightly narrowing anteriad, anterolateral corners slightly projecting anteriad; lateral margins arcuate; pronotal
surface flat, without grooves or distinct sculpture.
Prosternum anterior to procoxae moderately long,
elevated or carinate medially; prosternal process
short. Procoxal cavities contiguous. Posterior
prothoracic opening wide, transverse fold well
developed.
Mesothorax. Mesoventrite with lateral wing-like
projections, wide at anterior margin; anapleural
sutures strongly curved, subparallel anteriorly,
widely separated anteriorly; mesepimeron quadran-
717
gular. Mesocoxal cavities only very narrowly separated from each other. Scutellar shield rather small,
triangular, sharply pointed posteriorly. Elytron with
deeply impressed sutural stria and weakly impressed
series of fine punctures; epipleuron well developed,
rather wide anteriorly.
Metathorax. Metaventrite evenly flat, slightly
longer than mesoventrite, anteriorly narrowly projecting between mesocoxae, only weakly projecting
posteriad. Metanepimeron narrow, 2.9× as long as
wide, with a transverse oblique ridge anteriorly.
Metacoxal cavities transverse, contiguous mesally.
Legs moderately long, apices of femora c. reaching
body outline. Metacoxae transverse. Metatrochanter subtriangular. Metafemur with anteroproximal
portion free, not facing trochanter. Tibiae c. as long as
femora; meso- and metatibiae with longitudinal series
of small spines and longer apical spurs; mesotarsus
with basal tarsomere minute, tarsomere 2 much
longer, subequal in length to tarsomeres 3–4 combined, tarsomere 5 longest, bearing simply arcuate
claws.
Abdomen with five ventrites, posterior margin of
ventrite 5 with deep narrow emargination.
Differential diagnosis: Alegorius yixianus sp. nov.
differs from the unnamed below species in much
larger body size (c. 10–12 mm, in contrast to 6.4 mm
in Alegorius sp.).
Etymology: The species name refers to the Yixian
Formation, where the fossils of this species were
excavated.
ALEGORIUS
SP.
Material examined: CNU 2009081, piece only, from
the same locality as A. yixianus sp. nov.
Description: Body elongate oval; for measurements
see Table 1.
Head with distinct frontoclypeal suture reaching
lateral margin closely before eyes; clypeus large, probably weakly excised anteriorly; eyes rather large in
dorsal view; labrum transverse partly exposed anterior to clypeus.
Prothorax. Pronotum transverse, narrowing anteriad, anterolateral corners slightly projecting anteriad,
lateral margins arcuate.
Mesothorax. Anapleural sutures strongly curved,
widely separate and subparallel anteriorly. Elytra
with coarsely punctate longitudinal series; epipleuron
rather narrow anteriorly.
Metathorax. Metaventrite slightly longer than
mesoventrite; metanepisternum c. 3.5× as long as
wide.
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M. FIKÁČEK ET AL.
Abdomen with five ventrites, ventrite 1 with deep
and narrow apical emargination.
Legs rather long, mesotibiae reaching c. the body
outline, mesotibia slightly shorter than mesotibia.
Comments: Although the fossil is rather badly preserved, it bears diagnostic characters of Alegorius
(shallowly excised clypeus, strongly curved anapleural
and abdominal ventrite 5 with apical emargination)
and corresponds to A. yixianus sp. nov. in general body
shape. In contrast to the above species, it is much
smaller (6.4 mm) and therefore represents another
species. Due to the poor preservation of the fossil, we
refrain from naming the fossil here, pending the
discovery of better-preserved specimens.
BAISSALARVA
GEN. NOV.
Type species: Baissalarva hydrobioides sp. nov., by
present designation.
Time range: Early Cretaceous.
Diagnosis: Labrum fused with clypeus; labroclypeus
with five large teeth with slightly more isolated left
lateral-most one (Figs 3E, 6B); epistomal lobes low,
symmetrical (Fig. 3D–E); occipital foramen situated
dorsally (Figs 3E, 6A); mandible with three
retinacular teeth (Figs 3D, 6C); prothorax completely
sclerotized dorsally (Figs 3C, F, 6A, D); meso- and
metathorax with large transverse sclerites (Figs 3C,
F, 6A, D); abdominal segments largely membranous,
with small dorsal circular sclerites only (Figs 3C, F,
6A, D); tracheal system with a pair of large tracheal
trunks (Figs 3C, F, 6A, D).
Etymology: The generic name consists of the name of
the type locality in which the genus was found
(Baissa) and the ending -larva indicating that it represents the larval stage. Feminine.
Family assignment: The combination of dorsally situated occipital foramen of the head (present due to
the hyperprognathous head allowing it to hold the
prey above the water surface when it is processed
preorally) and the anterior margin of the head
bearing series of teeth on labroclypeus reliably
assigns the fossils to the family Hydrophilidae. The
family assignment is also supported by the general
habitus, which closely corresponds to those of larvae
of extant Hydrophilidae (see, e.g. Fig. 6E–H), and
by the presence of massive tracheal trunks in the
abdomen (an adaptation for breathing atmospheric
oxygen in submerged larvae).
Results of phylogenetic analysis: The unconstrained
analysis resulted in seven most parsimonious trees
207 steps in length. Their strict consensus tree
(Fig. 4A) is largely unresolved, but Baissalarva is still
recognized to form a group with all included genera
of the Hydrobiusini and the hydrophiline genus
Sternolophus based on the nasale with five teeth and
the left-most one distinctly separated from the other.
In the constrained analysis using the molecules-based
backbone tree, a single most parsimonious tree of
length 240 steps was found (Fig. 4B). Baissalarva is
placed as a sister taxon to the extant representatives
of the Hydrobiusini based on characters of the nasale.
Comparison with other genera: The presence of five
teeth of labroclypeus with the left one slightly more
separated from the others is very characteristic
for the modern larvae of the tribe Hydrobiusini and
the hydrophiline genus Sternolophus Solier, 1834
(Archangelsky, 1997, 2004; Minoshima & Hayashi,
2011a, b, 2012b). The form of the nasale (i.e. characters 5 and 6) is also responsible for grouping
Baissalarva with these taxa in both phylogenetic
analyses performed. Comparison of Baissalarva with
modern representatives of the Hydrobiusini (Fig. 6E,
G) and Sternolophus (Fig. 6F, H) shows that the fossil
resembles the hydrobiusine larvae (mandibles wide
with wider retinacular teeth, head widely quadratic,
anterior margin of the occipital foramen arcuate,
cervical sclerites wide, abdominal segments 1–8 with
two pairs of isolated sclerites). At the same time, it
clearly differs from the larva of Sternolophus, which
has long slender mandibles and retinacular teeth,
elongate head, triangular anterior margin of the
occipital foramen, very narrow cervical sclerites, and
mesonotum with both pairs of tergites fused). All
these characters are shared by all other genera of the
Hydrophilini except Hydrophilus Geoffroy, 1762.
Comparison of the fossils with modern larvae hence
corresponds well with the results of our constrained
analysis, and we consider Baissalarva as belonging
to the tribe Hydrobiusini. Knowledge of the extant
larvae of the Hydrobiusini is still rather limited and
the fossils lack the generic diagnostic characters
(chaetotaxy, detailed morphology of mouthparts and
antenna). For this reason we prefer to assign the
fossil to a new fossil genus, Baissalarva gen. nov.
BAISSALARVA
HYDROBIOIDES SP. NOV.
Type locality and age: Russia, Buryat Republic,
Baissa. Early Cretaceous, Berriasian–Hauterivian, c.
146–135 Mya (Zherikhin et al., 1998; D. V. Vassilenko,
pers. comm to A.P., 2011).
Type material (two specimens): Holotype: PIN 3063/
6975, piece and counterpiece (Figs 3D–F, 6A–C).
Paratype: PIN 3063/6977, piece only (Figs 3C, 6D).
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MODERN HYDROPHILID CLADES IN THE MESOZOIC
719
Figure 3. Early Cretaceous representatives of the Hydrobiusini. Cretoxenus australis gen. nov., sp. nov., Koonwarra,
Australia, NMVP 103312, piece and counterpiece (A, B). Baissalarva hydrobioides gen. nov., sp. nov. from Baissa,
Russia: paratype PIN 3063/6977 (C); holotype PIN 3063/6975: piece, detail of the head (D), counterpiece, detail of the head
(E), whole specimen, counterpiece (F). Abbreviations: absc, abdominal dorsal sclerite; absc4, absc7, abdominal dorsal
sclerite of segment 4 or 7; aes3, metanepisternum; apls, anapleural suture; cersc, cervical sclerite; dpl8, dorsal plate on
abdominal segment 8; epl, epistomal lobe; md, mandible; men, mentum; mssc, mesoscutum; mstr1, mesotarsomere 1; msv,
mesoventrite; mxp, maxillary palpus; mtsc, metascutum; ns, nasale; occf, occipital foramen; pros, prosternum; sbm,
submentum; scsh, scutellar shield; sstr, sutural stria; ttr, tracheal trunk.
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M. FIKÁČEK ET AL.
Figure 4. Results of the phylogenetic analyses of the position of Baissalarva hydrobioides. Unconstrained analysis, strict
consensus of seven most-parsimonious trees of 207 steps (A); single most parsimonious tree of length 240 steps resulting
from the constrained analysis (B).
Description: Body length c. 10.0 mm, head width c.
1.2 mm; body elongate.
Head c. as long as wide, with large occipital
foramen situated dorsally. Anterior margin with
dentate nasale mesally, bearing five large teeth with
the left one (seen on the right in the respective
fossil) slightly more separated from remaining ones;
anterolateral part with symmetrical, low arcuate
epistomal lobes. Frontal lines weakly developed,
converging towards posterior margin of head, coronal suture at most very short. Eyes present
posterolaterally of epistomal lobes consisting of separate stemmata. Mandible long and falcate, with
three inner teeth, two distal ones large, proximal one
small. Submentum trapezoidal, narrowing anteriad,
submental suture angulate medially, well developed.
Gula reduced, gular sutures fused into a single
median line. Cervical sclerites present, transverse.
Thorax. Pronotum completely sclerotized, proscutum subdivided by fine sagittal line. Mesonotum
with one pair or large subtriangular transverse
sclerites subdivided into darker anterior and paler
posterior parts. Metanotum anteriorly with a pair
of large transverse sclerites subdivided into anterior
and posterior portion in the same way as on
mesonotum. Posterior portion of metanotum with
another pair of more weakly delimited and smaller
sclerites.
Abdomen largely membranous, bearing only minute
sclerites dorsally. Abdominal segments 1–7 each with
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MODERN HYDROPHILID CLADES IN THE MESOZOIC
two pairs of minute sclerites, anterior ones darker,
ring-like, more distinctly delimited, posterior ones
paler and more weakly delimited. Abdominal segment
8 with small dorsal plate. Internal portion of abdomen
with two massive tracheal trunks, segments 1–7
without evident spiracles.
Etymology: The species name refers to the extant
genus Hydrobius, a representative of the tribe
Hydrobiusini to which Baissalarva belongs.
CRETOXENUS
GEN. NOV.
Type species: Cretoxenus australis sp. nov., by present
designation.
Time range: Early Cretaceous.
Diagnosis: Body medium-sized, elongate oval; labrum
exposed in front of clypeus (Figs 3A, B, 8C); anterior
margin of clypeus concave (Figs 3A, B, 8C); maxillary
palpi long (Fig. 3A, B); prosternum moderately
long (Fig. 3A); procoxae contiguous; scutellar shield
small, triangular; anapleural sutures of mesothorax
well developed, nearly straight, converging anteriad
(Figs 3A, 6I, 8D); mesanespisterna narrowly separate
by mesoventrite anteriorly (Figs 3A, 6I, 8D); mesocoxal
cavities very narrowly separated from each other;
metaventrite prolonged into a triangular process posteriorly (Figs 3A, 6A, 8D); metanepisternum rather
narrow; elytron with punctate series (Fig. 3A, B);
sutural stria present, deeply impressed.
Etymology: The genus name consists of the prefix
creto- referring to its Cretaceous age, and the ending -xenus indicating that the fossil is in some
characters similar to the extant genus Limnoxenus.
Masculine.
Family assignment: The combination of the antenna
with antennal club, head not constricted behind eyes,
presence of long maxillary palpi, small triangular
scutellar shield, and femora with anteromesal corner
not facing trochanter assign the fossil reliably to the
family Hydrophilidae s.s. Additionally, it corresponds
well with the modern Hydrophilidae in the general
habitus and ventral morphology.
Comparison with other hydrophilid genera: By the
combination of exposed labrum, medium body size,
long maxillary palpi, mesoventrite well separates
from mesanepisterna, and moderately long simple
prosternum, Cretoxenus resembles the modern genera
of the subfamilies Acidocerinae and Enochrinae,
and of the tribe Hydrobiusini of the subfamily
Hydrophilinae. It differs from the Enochrus clade of
721
the Enochrinae by the nearly straight anapleural
sutures (S-shaped in the Enochrus clade) and from
the Cymbiodyta clade of the same subfamily by short
mesotarsomere 1 (basal tarsomere is reduced in mesoand metathoracic legs in all representatives of the
clade). The combination of the sutural stria, distinct
elytral series of punctures, and long maxillary
palpi distinguishes it from modern genera of the
Acidocerinae. The non-denticulate lateral margins
distinguish the fossil from the ‘sperchopsine’ genera
of the Hydrobiusini. However, the posteriorly projecting mesal portion of the metaventrite corresponds
with that present today in many Hydrobiusini
(e.g. Limnoxenus Motschulsky, 1853; Fig. 6K, L),
some of which (Limnocyclus, Hybogralius Orchymont,
1942) even share with the fossil the nearly straight
anapleural sutures of the mesothorax. The presence
of long maxillary palpi and exposed clypeus also diagnoses the new genus from the Rygmodinae (which
have concealed labrum and/or shorter and stouter
maxillary palpi) many of which are otherwise also
similar to the Hydrobiusini in general habitus. The
fossil hence very likely belongs to the modern tribe
Hydrobiusini of the subfamily Hydrophilinae; the
above characters as well as the age of the fossil justify
its separate generic status.
For the diagnosis from the Late Jurassic
Protochares gen. nov., see above under that genus.
Cretoxenus differs from remaining two Early Cretaceous genera Alegorius gen. nov. and Hydroyixia gen.
nov., by the combination of nearly straight anapleural
sutures converging anteriad (subparallel anteriorly
in Alegorius, converging but weakly angulate in
Hydroyixia), deeply arcuately excised anterior margin
of clypeus (shallowly excised in Alegorius, with wide
subtrapezoid excision in Hydroyixia), and large
exposed labrum (narrowly exposed in Alegorius,
embedded in the clypeal excision in Hydroyixia; see
Table 2 and Fig. 8C, D for details).
CRETOXENUS
AUSTRALIS SP. NOV.
Coleoptera indet.: Jell & Duncan 1986: fig. 40I–K.
Type locality and age: Australia, Victoria State,
Koonwarra Fossil Bed, road cutting on South
Gippsland Highway, 1.5 miles west of Tarwin & 2.5
miles east of Koonwarra (93.5 miles south-east of
Melbourne). Korumburra Group, Early Cretaceous,
Late Aptian, c. 118–112 Mya (Dettmann, 1986; Jell &
Duncan, 1986).
Type material: Holotype: NMVP 103312, piece and
counterpiece, partly damaged (Figs 3A–B, 6I–J).
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M. FIKÁČEK ET AL.
Description: Body elongate oval, body length 7.7 mm,
width of head 1.5 mm, width of pronotum 2.7 mm,
elytral length 4.7 mm.
Head c. as long as wide. Clypeus slightly explanate
laterally, shallowly concave on anterior margin. Eyes
moderately large, oval, divided by c. 2.3× the width
of one eye; postocular bridge not developed. Gula
slightly narrowing anteriad, weakly carinate medially
in posterior portion; gular sutures widely separate
from each other. Labrum rather large, well sclerotized,
transverse, attached to anterior margin of clypeus.
Antenna with terminal club. Maxillary palpi slender
and long, probably as least as long as width of
head.
Prothorax. Pronotum transverse, slightly narrowing anteriad, anterolateral corners slightly progressing anteriad; lateral margins arcuate, finely rimmed;
pronotal surface flat, without grooves or distinct
sculpture. Prosternum anterior to procoxae moderately short, prosternal process simply projecting
between procoxae, median portion of prosternum
without distinct carina. Procoxal cavities contiguous.
Posterior prothoracic opening wide, transverse fold
well developed.
Mesothorax. Mesothorax with narrow anterior
collar; mesoventrite triangular, strongly narrowed
anteriad, rather narrow on anterior margin;
anapleural sutures well developed, slightly arcuate;
mesepimeton quadrangular. Mesocoxal cavities only
very narrowly separated from each other. Scutellar
shield rather small, triangular, sharply pointed
posteriorly. Elytron with deeply impressed sutural
stria and weakly impressed series of fine punctures;
epipleuron well developed, rather wide anteriorly, subdivided by a ridge into a narrower outer and wider
inner portion.
Metathorax. Metaventrite c. as long as mesoventrite,
posteriorly narrowly projecting between metacoxae,
its median portion probably slightly elevated at
least posteriorly. Metanepimeron narrow, 4.1× as long
as wide. Metacoxal cavities transverse, contiguous
mesally.
Legs moderately long, apices of femora c. reaching
body outline. Procoxae globular, mesocoxae transversely oval, metacoxae transverse. Metatrochanter
sinuate on inner margin. Tibiae c. as long as femora.
Mesotibia with two dorsal longitudinal series of small
spines, third series of spines present on its posterior
face; apical portion of mesotibia with series of moderately long spurs. Mesotarsus with very short basal
tarsomere, tarsomere 2 rather long.
Abdomen with five ventrites.
Etymology: The species name refers to Australia, i.e.
the country of origin of the fossil.
HYDROYIXIA
GEN. NOV.
Type species: Hydroyixia elongata sp. nov., by present
designation.
Time range: Early Cretaceous.
Diagnosis: Body medium-sized; labrum partly
exposed in dorsal view (Figs 5A, D, F, 7J, 8E); anterior margin of clypeus deeply and widely excised
mesally (Figs 5A, D, F, 7J, 8E); prosternum moderately long; scutellar shield small, triangular;
anapleural sutures well developed, weakly curved,
converging anteriad; mesoventrite very narrow anteriorly (Figs 5B, I, 7I, K, 8F); mesocoxae very narrowly
separated; abdomen with five ventrites; apical
abdominal ventrite with shallow wide emargination (Figs 5B, F–G, I, 7L–M); elytron with deeply
impressed sutural stria (Figs 5A, C, F, I); elytra
with series of punctures (Figs 5C, F, I); elytral
trichobothria very distinct (Fig. 5E); metathoracic leg
with five tarsomeres; mesotarsomere 1 very short
(Fig. 5H).
Etymology: The generic name consists of the prefix
hydro- referring to the Hydrophilidae, and the ending
-yixia referring to the Yixian Formation from which
both species of this genus are described. Feminine.
Family assignment: The combination of large clypeus,
well-developed frontoclypeal sutures reaching lateral
margin of head closely before eyes, head not constricted behind eyes, and the small triangular
scutellar shield assigns the fossil reliably to the
family Hydrophilidae s.s. Additionally, it corresponds
well with the modern aquatic groups of the Hydrophilidae in general habitus, ventral morphology, and
the presence of very distinct trichobothria on elytra
and pronotum.
Comparison with other hydrophilid genera: Based
on the presence of the apical emargination on the
posterior margin of the abdominal ventrite 5,
Hydroyixia resembles the extant representatives of
the Hydrobiusini, early branching Hydrophilini,
Enochrinae, and Acidocerinae. In contrast to the
Hydrophilini, the meso- and metaventrite of Hydroyixia are not fused into a common ventral keel and
the posterior leg lacks series of swimming hairs. In
contrast to the Cymbiodyta clade of the Enochrinae,
the metathoracic leg bears five tarsomeres. The
mesoventrite narrowing anteriad is not known in
any extant genus of the Enochrinae, and in the
Acidocerinae only occurs in few clades of the
Helochares group (e.g. genus Peltochares Régimbart,
1907 and Helochares obscurus species group, from
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MODERN HYDROPHILID CLADES IN THE MESOZOIC
723
Figure 5. Well-preserved specimens of Hydroyixia gen. nov., Yixian Formation, China. Hydroyixia elongata sp. nov.:
holotype CNU 2010005, piece and counterpiece (A, B); paratype CNU 2009075, whole specimen (C), detail of head and
pronotum (D); detail of elytral apices (E). Hydroyixia latissima sp. nov.: holotype, CNU 2009074, whole specimen (F),
detail of abdominal apex (G); posterior leg of paratype CNU 2010014 (H); paratype CNU 2009107 (I). Abbreviations: abem,
apical emargination of abdominal ventrite 5; aes3, metanepisternum; apls, anapleural sutures; cl, clypeus; fcs,
frontoclypeal suture; gs, gular suture; lb, labrum; men, mentum; msv, mesoventrite; mtv, metaventrite; mttr1,
metatarsomere 1; pros, prosternum; sstr, sutural stria; trich, trichobothrium.
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
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M. FIKÁČEK ET AL.
Figure 6. Fossil and recent representatives of the Hydrobiusini and Hydrophilini. Baissalarva hydrobioides sp. nov.:
holotype PIN 3063/6975, anterior part of the piece (A), detail of the head of the piece (B), detail of the head of the
counterpiece (C); paratype PIN 3063/6977 (D). Larva of extant Limnoxenus niger (Hydrobiusini): whole larva in dorsal
view (E), detail of head (G). Larva of extant Sternolophus rufipes (Hydrophilini): whole larva in dorsal view (F), detail of
head (H). Holotype of Cretoxenus australis sp. nov. NMVP 103312, piece and counterpiece (I, J). Extant hydrobiusine
Limnoxenus zealandicus in ventral view, whole beetle (K) and detail of meso- and metaventrite (L). Abbreviations: md,
mandible; mtvpr, metaventral process.
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MODERN HYDROPHILID CLADES IN THE MESOZOIC
725
Figure 7. Hydrophilid fossils from Early Cretaceous Yixian Formation, China. Alegorius yixianus sp. nov.: holotype
CNU 2009079, whole specimen (A), detail of meso- and metaventrite (B), detail of abdominal apex (C); paratype CNU
2009078, whole specimen (D), detail of mesoventrite (E). Hydroyixia elongata sp. nov.: paratype CNU 2009075, detail
of head and pronotum (F), whole specimen (G); holotype CNU 2010005: whole beetle, piece and counterpiece (H, I), detail
of head (J), detail of meso- and metaventrite (K), detail of abdominal apex (L). Hydroyixia latissima sp. nov.: holotype
CNU 2009074, detail of abdominal apex (M), whole specimen in dry condition (N) and under alcohol (O). Abbreviations:
apls, anapleural suture; abem, apical emargination of abdominal ventrite 5.
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M. FIKÁČEK ET AL.
Figure 8. Reconstructions of the clypeus shape and meso- and metathoracic morphology of the Early Cretaceous
hydrophilid genera known in adult stage (three-dimensional structure of the mesoventrite not reconstructed). Alegorius
gen. nov. (A, B); Cretoxenus gen. nov. (C, D); Hydroyixia gen. nov. (E, F). Head and thorax of the respective genus
not to scale.
Table 2. Differential diagnoses of Mesozoic genera of the Hydrophilidae known in adult stage and described in this paper
Protochares
Cretoxenus
Alegorius
Hydroyixia
Labrum
Maxillary palps
Prosternum
?Partly exposed
Short
?
?Not excised
Anapleural sutures
Anapleural sutures anteriorly
Mesoventrite anteriorly
Metaventrite posteriorly
?
?
?
?
Apex of abdominal ventrite V
?
?
Partly exposed
?Long
Moderately long,
?carinate
With shallow convex
emargination
Strongly curved
Subparallel
Wide
Not projecting
posteriad
With deep narrow
emargination
Partly exposed
?
? Long, ?carinate
Anterior margin of clypeus
Completely exposed
Long
Moderately long,
without carina
With shallow convex
emargination
Straight
Converging
Narrow
Projecting posteriad
which Hydroyixia gen. nov. differs by the presence of
the sutural stria). Angular excision of the clypeus is
present in the sperchopsine clade of the Hydrobiusini
(which differ from Hydroyixia by denticulate lateral
margins of elytra) and in many genera of the
Acidocerinae. Many aquatic taxa of the Acidocerinae
are also characterized by very conspicuous trichobothria on pronotum and elytra, which corresponds to
some specimens of Hydroyixia. The combination of
With wide angular
emargination
Weakly curved
Converging
Narrow
Not projecting
posteriad
With shallow wide
emargination
characters present in Hydroyixia hence assigns it best
to the Acidocerinae.
HYDROYIXIA
ELONGATA SP. NOV.
Type locality and age: China, Liaoning Province,
Shangyuan County, Chaomidian Village, Huangbanjigou, Yixian Formation, Early Cretaceous, Lower
Cretaceous, Aptian, 124.6 Mya (Swisher et al., 1999).
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MODERN HYDROPHILID CLADES IN THE MESOZOIC
An alternative dating was proposed by Zheng
et al. (2003): Jurassic–Cretaceous boundary, Late
Tithonian to Berriasian, c. 145–140 Mya. See Ren
et al. (2010) for discussion on various datings of the
formation.
Material examined (two specimens): Holotype: CNU
2010005, piece and counterpiece (Figs 5A, B, 7H–L).
Paratype: CNU 2009075, piece only (Figs 5C–E,
7F–G).
Description (characters seen only in the paratype
marked by an asterisk).
Body narrowly elongate. For body measurements
see Table 1.
Head. Clypeus large, slightly expanding laterally;
frontoclypeal sutures very distinct, reaching lateral
margin of head closely before eyes; anterior margin
widely excised, excision angular laterally; dorsal
surface finely and densely punctated*. Eyes rather
large, separated by 2.3–2.6× the width of one eye.
Labrum transverse, partly exposed anterior to
clypeus, slightly narrowing posteriad*, weakly convex
on anterior margin. Gula narrowing anteriad, with
longitudinal ridge mesally, gular sutures widely separated. Mentum large, subrectangular, c. 2.0× wider
than long.
Prothorax. Pronotum transverse, slightly narrowing anteriad, anterolateral corners slightly projecting
anteriad; lateral margin arcuate, with a narrow bead;
lateral portions with a group or trichobothria much
larger than ground punctation*. Prosternal process
wide and short, procoxae contiguous.
Mesothorax. Mesoventrite subtriangular, extremely
narrow at anterior margin; mesal portion probably
with an elevated carina. Anapleural sutures well
developed, slightly curved, converging anteriad, joint
at anterior margin of mesoventrite. Mesepimeron
subtriangular. Mesocoxae only narrowly separated.
Elytra combined nearly parallel-sided, each elytron
with sharply impressed sutural stria reaching c.
elytral midlength; elytra with finely punctate elytral
series*, serial punctures only slightly larger than
interval punctation*, alternate elytral intervals with
large and very conspicuous trichobothria; epipleuron
well developed anteriorly, rather wide, subdivided
into outer and inner portion.
Metathorax. Metaventrite c. as long as mesoventrite,
probably at least slightly elevated mesally, narrowly
projecting between mesocoxae anteriorly; only slightly
projecting posteriad. Anepisternum 3.1× as long as
wide.
Abdomen with five ventrites, ventrite 1 probably
weakly carinate anteriorly, without carina in posterior portion. Ventrite 5 with shallow wide apical
emargination.
727
Differential diagnosis: Hydroyixia elongata sp. nov.
differs from the following species especially in the
narrowly elongate body shape (widely elongate
in H. latissima), parallel-sided elytra (widest anteriorly and narrowing posteriad in H. latissima), distinctly larger mentum (small in H. latissima) and
metaventrite c. as long as mesoventrite (much longer
than mesoventrite in H. latissima).
Etymology: The species name refers to the elongate
body shape of this species.
Comments: The paratype of H. elongata differs from
the holotype by rather significantly larger body size
(body length 11.8 mm compared with 8.3 mm of the
holotype), which may indicate it is in fact not
conspecific with the holotype. Still, both specimens
correspond well in body proportions and the size of
the mentum considered by us as diagnostic characters, and the variation of the body size (35%) is still in
the range observed in variable species of the extant
Acidocerinae. Unfortunately, the ventral characters
are not preserved in the paratype, and its wellpreserved characters of the dorsal surface (e.g.
trichobothria) cannot be compared with the holotype
in which the dorsal portion is rather poorly preserved.
We hence tentatively consider both specimens as representing a single species.
HYDROYIXIA
LATISSIMA SP. NOV.
Type locality and age: China, Liaoning Province,
Shangyuan County, Chaomidian Village, Huangbanjigou, Yixian Formation, Early Cretaceous, Lower Cretaceous, Aptian, 124.6 Mya (Swisher et al., 1999). An
alternative dating was proposed by Zheng et al. (2003):
Jurassic–Cretaceous boundary, Late Tithonian to
Berriasian, c. 145–140 Mya. See Ren et al. (2010) for
discussion on various datings of the formation.
Material examined (three specimens): Holotype: CNU
COL LB 2009074, piece only (Figs 5F–G, 7M–O).
Paratypes: CNU COL LB 2009107, piece only
(Fig. 5I); CNU COL LB 2010014, piece only, with
detached posterior leg (Fig. 5H).
Description: Body widely oval. For body measurements see Table 1.
Head. Clypeus large; frontoclypeal sutures very distinct, reaching lateral margin of head closely before
eyes; anterior margin excised, excision angular laterally. Eyes rather large, separated by 2.3× the width of
one eye. Labrum transverse, partly exposed anterior
to clypeus, slightly narrowing posteriad, weakly
convex on anterior margin. Gula narrowing anteriad,
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
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M. FIKÁČEK ET AL.
with longitudinal ridge mesally, gular sutures widely
separated. Mentum rather small, subrectangular, c.
2.4× wider than long.
Prothorax. Pronotum transverse, slightly narrowing anteriad; lateral margin arcuate. Prosternum
probably rather long, with median elevation or
carina. Procoxae contiguous.
Mesothorax. Mesoventrite subtriangular, extremely
narrow at anterior margin. Anapleural sutures well
developed, slightly curved, converging anteriad, joint
at anterior margin of mesoventrite. Mesepimeron
large, subtriangular. Mesocoxae only narrowly separated. Scutellar shield small, triangular, pointed posteriorly. Elytra combined widest anteriorly; each
elytron with sharply impressed sutural stria; elytra
with coarsely punctate elytral series; epipleuron well
developed anteriorly, moderately wide.
Metathorax. Metaventrite much longer than
mesoventrite, probably not elevated mesally, narrowly projecting between mesocoxae anteriorly; only
slightly projecting posteriad. Anepisternum 4.4× as
long as wide.
Abdomen with five ventrites; ventrite 5 with
shallow wide apical emargination.
Differential diagnosis: For differential diagnosis from
H. elongata see above under that species.
Etymology: The species name refers to the wide body
of this species.
DISCUSSION
HYDROPHILIDAE
DATED BACK TO THE
LATE JURASSIC
The fossils described in this paper represent first
records of the Hydrophilidae s.s. from the Mesozoic
and clearly document that the family was well established already by the Late Jurassic. In this respect,
Hydrophilidae s.s. corresponds to the Helophoridae,
the occurrence of which in the Late Jurassic was
documented by Fikáček et al. (2012a, b). Although
the phylogenetic relationships of the hydrophiloid
families remain unresolved (e.g. Hansen, 1991;
Archangelsky, 1998; Beutel & Komarek, 2004;
Bernhard et al., 2006, 2009), the Helophoridae and
the Hydrophilidae seem not to be closely related and
each of them probably represents a different clade of
the superfamily Hydrophiloidea (the helophorid
lineage in the case of the Helophoridae, the
hydrophilid lineage in the case of the Hydrophilidae;
see, for example, Hansen 1991 and Archangelsky
1998, 2007 for details). The fact that both these
families were well established by the Late Jurassic
hence indicates that the remaining four extant
hydrophiloid families (Georissidae, Epimetopidae,
Hydrochidae, and Spercheidae) were very likely
already differentiated by the same time. In addition,
extinct hydrophiloid clades were also present in the
Mesozoic (Fikáček et al., 2012a, b).
The presence of the Early Cretaceous fossils that
may be reliably assigned to the extant tribes is rather
surprising. For example, it indicates that the tribes
Hydrobiusini and Hydrophilini diverged c. 90 Myr
earlier than it was supposed: the minimum age of the
divergence was until now dated to the middle Eocene
(47 Mya) based on the fossils from the Messel Pit
locality in Germany (Fikáček et al., 2010a), and is now
shifted to the Early Cretaceous (c. 140 Mya) based on
the above described fossils of Baissalarva gen. nov. and
Cretoxenus gen. nov. The same is true for the subfamily
Acidocerinae, which may be dated back to c. 126 Mya
based on the above-described fossils of Hydroyixia
gen. nov. The position of Baissalarva in the extant
Hydrobiusini is especially well supported by the morphology of the nasale (bearing five teeth and the
left-most tooth more separated from remaining teeth).
Estimated ages for hydrophilid clades on the basis of
previously known fossil records have been questioned
based on the current distribution of several extant
clades exhibiting fingerprints of possible ancient
Gondwanan distribution (see Short & Fikáček 2013 for
details). Our present results are congruent with these
indirect clues, confirming that previous age estimates
were far too young for the family Hydrophilidae and its
subgroups.
All adult-stage fossils described in this contribution
are characterized by a rather generalized morphology,
as are also extant representatives of the Hydrobiusini
and Acidocerinae. Both above extant groups lack
apparent clade-specific apomorphies and are mostly
characterized by combinations of plesiomorphic character states (Short & Fikáček, 2013). This stands,
together with the occurrence of these generalized
forms in the Late Jurassic and Early Cretaceous, in
contrast to the phylogenetic positions of both clades,
which were resolved as rather deeply nested in the
Hydrophilidae rather than early branching (Short &
Fikáček, 2013). Two possible scenarios may explain
this seeming contradiction: either a parallel independent ‘return’ to generalized morphology in several
hydrophilid clades, or a long-term survival of the
generalized stem-group taxa from which morphologically derived clades diverged sequentially. The
first scenario would suppose that even the Late
Jurassic fossils were already members of the extant
general-looking clades, whereas the second scenario
would expect them to be either stem-group taxa of
representatives of modern clades. Dating of the
principal divergences of the hydrophilid tree and/or
discovery of better-preserved Jurassic fossils of the
Hydrophilidae may help to distinguish between
these two scenarios. Regardless, the occurrence of
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
MODERN HYDROPHILID CLADES IN THE MESOZOIC
the Hydrobiusini and Acidocerinae in the Early
Cretaceous implies that many morphologically
derived groups (e.g. Amphiopini, Berosini, Laccobiini,
Chaetarthriini) were already present at that time and
may be found in the fossil record. Their small body size,
globular body (which is frequently deformed during
fossilization), and the loss of some easy-to-preserve
hydrophilid synapomorphies (e.g. frontoclypeal suture,
long maxillary palps) may explain why they were
overlooked or not yet discovered in the fossil record.
HYDROPHILIDAE WIDELY DISTRIBUTED
LATE JURASSIC
BY THE
The second surprising result of this study besides the
Mesozoic age of the whole family and its extant tribes
is the wide distribution of the Hydrophilidae in the
Late Jurassic and Early Cretaceous. We have documented here the occurrence in both the northern and
southern hemispheres during the Late Jurassic (c.
150 Mya) for the Hydrophilidae (based on the fossils
729
from Solnhofen, Germany, and Talbragar, Australia)
and during the Early Cretaceous (c. 130–120 Mya) for
the extant tribe Hydrobiusini (based on Baissalarva
from Baissa, Russia, and Cretoxenus from Koonwarra,
Australia).
The worldwide occurrence of the Hydrophilidae in
the Late Jurassic is possibly a result of the connections
between the southern and northern continental blocks
that existed during the Jurassic (e.g. Sanmartín &
Ronquist, 2004; Ezcurra & Agnolín, 2012). A temporal
lag is expected between the origin of the clade (family
Hydrophilidae in our case), origin of its synapomorphies, and its appearance in the fossil record
(Magallón, 2004). In the same way, a temporal lag may
be expected between the origin of the clade, achievement of a worldwide distribution, and the appearance
in the fossil record. The length of the time lag is
generally impossible to estimate, but we suppose that
the worldwide distribution of the family may imply its
Early–Middle Jurassic origin. This is not in the conflict
with the fossil-dated molecular trees of Coleoptera
Figure 9. Known distribution of the Hydrophilidae in the Late Jurassic and Early Cretaceous. 1, Solnhofen, Germany;
2, Talbragar, Australia; 3, Baissa, Russia; 4, Yixian Formation, China; 5, Koonwarra, Australia.
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
730
M. FIKÁČEK ET AL.
available at the moment, which date the origin of the
Hydrophiloidea back to the Jurassic (175 ± 23 Mya;
Hunt et al., 2007) or Triassic (228 Mya, McKenna &
Farrell, 2009). It shouls soon be possible to compare
our hypothesis with the dated Hydrophilidae tree.
Moreover, the occurrence of the extant clade
Hydrobiusini in Gondwana (Koonwarra) and eastern
Laurasia (Baissa) suggests that the principal extant
clades may have diverged as early as the Jurassic
when a worldwide distribution was easy to establish.
This would explain the current worldwide distribution of most hydrophilid tribes (Short & Fikáček,
2013) or even of genera (e.g. Berosus, Enochrus,
Helochares; Hansen, 1999; Short & Hebauer, 2006;
Short & Fikáček, 2011). However, this hypothesis
needs to be confirmed based on a dated molecular
phylogeny of the Hydrophilidae.
ACKNOWLEDGEMENTS
We are indebted to A. Lukeneder (NHMW) and
R. Schmidt (NMVP) for allowing us to visit the
collections under their care, to D. V. Vassilenko
(Paleontological Institute, Russian Academy of Sciences, Moscow) for discussion on the geology and
stratigraphy of fossil deposits, and to A. E. Z. Short
(University of Kansas, Lawrence, USA) and an
anonymous reviewer for critique of the manuscript
and numerous language corrections. The study was
supported by grant KJB301110901 from the Czech
Academy of Sciences (GAAV), the institutional
resources of the Ministry of Culture of the Czech
Republic for the support of science and research
(DKRVO 2012 and DKRVO 2013/12, National
Museum, 00023272) and grant MSM0021620828
from the Ministry of Education of the Czech Republic
to M.F., a grant of the Russian Foundation for
Basic Research (12-04-0063-a) to A.P., China Postdoctoral Science Foundation funded project (No.
2012M511808) and the Research Fellowship for International Young Scientists 2013Y1ZB003 to Y.Y., grant
no. 123112 by the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology
and Palaeontology, CAS to Y.Y., the Research Fellowship from the Alexander von Humboldt Foundation to
B.W., the National Basic Research Program of China
(973 Program; grant 2012CB821906), the National
Natural Science Foundation of China (grants
31230065, 41272006), and Project of Great Wall
Scholar and KEY project of Beijing Municipal Commission of Education (grant KZ201310028033) to D.R.
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Appendix Table 3. List of characters used for the analysis of the phylogenetic position of Baissalarva hydrobioides
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
Head (Arch 4): (0) prognathous; (1) hyperprognathous.
Frontal sutures (Arch 6): (0) converging posteriad; (1) not converging posteriad.
Coronal suture (Arch 7): (0) absent; (1) present.
Nasale (Arch 8): (0) symmetrical; (1) asymmetrical.
Number of teeth of nasale: (0) none; (1) single median; (2) two; (3) three; (4) four; (5) five; (6) six; (7) multiple
small.
Left-most tooth more separated from the remaining teeth: (0) no; (1) yes.
Epistomal lobes (Arch 10, modified): (0) symmetrical or almost so; (1) strongly asymmetrical.
Station of epistomal lobes (Arch 11): (0) both with at least 3 setae; (1) only left one with setae; (2) both with less
than 3 setae.
Left epistomal lobe (Arch 12): (0) without pubescence; (1) with pubescent emargination.
Number of sensory appendages of antenna (Arch 13): (0) two; (1) one.
First antennal segment (Arch 14): (0) bare; (1) with a strong distal inner seta; (2) with numerous inner setae.
Size of antennal sensorium (Arch 15, modified): (0) minute; (1) distinctly shorter than antennomere 3; (2) c. as
long as antennomere 3.
Mandibles (Arch 16, modified): (0) symmetrical or nearly so; (1) strongly asymmetrical.
Number of retinacular teeth of left mandible (Arch 17): (0) none; (1) one; (2) two; (3) three; (4) with comb-like
structures.
Number of retinacular teeth of right mandible (Arch 18): (0) none; (1) one; (2) two; (3) three.
Stipes (Arch 20): (0) bare; (1) with basal cuticular spines; (2) with spines along its inner margin.
Stipes (Arch 21): (0) without pubescence; (1) pubescent.
Stipes (Arch 22): (0) with five inner setae; (1) with inner row of at least 9 setae.
Distal apex of stipes (Arch 23): (0) without spine; (1) ending by a spine.
Inner appendage of maxilla (Arch 25): (0) sclerotized; (1) unsclerotized.
First palpal segment (Arch 26): (0) completely sclerotized; (1) incompletely sclerotized.
Palpal segment 1 (Arch 27, modified): (0) minute; (1) shorter than stipes; (2) as long as or longer than stipes.
Ligula (Arch 31, modified): (0) absent; (1) present.
Ligula: (0) not overlapping labial palps; (1) overlapping labial palps.
Dorsal surface of mentum (Arch 33): (0) without spines; (1) with spines.
Hypopharyngeal lobe (Arch 32): (0) absent; (1) present.
Mentum (Arch 34): (0) less than 2x wider than prementum; (1) more than 2x wider than prementum.
Prementum (Arch 37): (0) sclerotized in a ring; (1) largely membranous, with ventral sclerites.
Labial palps (Arch 38): (0) bare; (1) with cuticular projections on membranes; (2) with projections on membrane
and segments.
Cervical sclerites (Arch 39): (0) absent; (1) present.
Number of stemmata (Arch 40): (0) six; (1) fused.
Larvae (Arch 41): (0) holopneustic; (1) metapneustic; (2) apneustic.
Spiracular atrium (Arch 42, modified): (0) absent; (1) present.
Legs (Arch 43): (0) visible in dorsal view; (1) not visible in dorsal view.
Legs (Arch 44): (0) five-segmented; (1) reduced, with 3 segments or less.
Claws (Arch 45): (0) pointed; (1) rod-like; (2) absent.
Pleural area (Arch 46): (0) sclerotized; (1) membranous.
Femur and tibiotarsus (Arch 47): (0) with swimming hairs; (1) without swimming hairs.
Thoracic tergites (Arch 48): (0) present on pro-, meso- and metathorax; (1) only present on prothorax.
Prosternum (Arch 49): (0) completely divided; (1) incompletely divided; (2) entire; (3) reduced.
Tergites on abdomen (Arch 50): (0) on segments I-VIII; (1) on segments I and VIII; (2) only on segment VIII.
Abdominal segments VIII-X (Arch 51): (0) unmodified; (1) modified.
Plate on segment VIII (Arch 52): (0) entire; (1) divided.
Large lateral lobes on abdomen: (0) absent; (1) present.
Lateral projections on segments 1–7: (0) absent; (1) present.
Lateral projections on abdominal segment 8: (0) absent; (1) present.
Urogomphi (Arch 53, modified): (0) large, 3-segmented; (1) reduced, not apparent.
Lateral lobes on pronotum: (0) absent; (1) present.
Posterior projections on abdominal tergite 8: (0) absent; (1) present.
The number of the respective character in Archangelsky (2004) is prefixed by ‘Arch’.
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734
734
M. FIKÁČEK ET AL.
Appendix Table 4. Morphological dataset used for the analysis of the phylogenetic position of Baissalarva hydrobioides
Species
1111111111222222222233333333334444444444
1234567890123456789012345678901234567890123456789
Helophorus orientalis
Phaenonotum exstriatum
Dactylosternum cacti
Cercyon praetextatus
Oosternum costatum
Sphaeridium scarabaeoides
Sperchopsis tessellata
Ametor scabrosus
Berosus auriceps
Hemiosus bruchi
Derallus angustus
Chaetarthria bruchi
Paracymus subcupreus
Paracymus rufocinctus
Laccobius minutoides
Oocyclus sp
Helochares maculicollis
Enochrus lampros
Enochrus tremolerasi
Hydrobius melaenus
Hydramara argentina
Tropisternus lateralis
Hydrophilus triangularis
Hydrophilus ovatus
Amphiops mater
Agraphydrus narusei
Enochrus japonicus
Hydrobius pauper
Sternolophus rufipes
Hydrochara affinis
Tormus helmsi
Rygmodus
Cylomissus glabratus
Anacaena suturalis
Guyanobius adocetus
Crenitis morata
Notionotus liparus
Hydrobiomorpha casta
Baissalarva
00001–00000002220000020–100010000000010000–00000–
1001300001020221111001101000111110000100111000100
10012–02010112201100010–0100110111000101110000100
11010–02110110101101010–0101011111121102210000100
11010–02110110101101010–0101011111121102210000100
11011–0211000000110111100100011111011102110001100
1011410001000331001011101000110110000102010100100
1011410001000331001011101000110110000100010100100
11017011011114300000010–000000020000011021–011100
11010–11011?1430000000100000110101000111211100100
1100700201120220000001101010010110000102110010101
1100300001020222000010111000010111120103011000100
1101400201020332000111101000210111000100010100100
1101700201020222000101111000210111000100010100100
11013011010214220000110–0000010110000100010100100
10013011010114320000110–1000210110000100010000100
1011600201010221000001101000210110000101110100100
1011700201011120000001101000210110000101110000100
1011700201010220000001101000210110000101110000100
1011510001000331001011101000210110000100010100100
1011510001000331001011101000210110000100010100100
1010700201200331000001101010010110000002110011101
10100–0201200110000001101010010110000002210011100
10100–0201201010000001101010010110000002210011100
10105002010203310000000–1010010110000102010100100
1011601201011121000011101000010110000001110000100
1011701201011120000000101000210110000000010000100
1011510001000331001001101000210110000100010100100
1011510001000331001001101010010110000102010011101
10100–0001200221000001101010010110000001010011101
11013100010203320000010–1000110111000100210100100
1010500001000220000011101000010110000102111100100
1010200201010220110011101000110110000102110100100
1101510001020332000112111000210111000101010000111
1000500001020332000011111000210111000100010100100
1101500001020332000002111000210111000100010100111
1001701201011230000001101000110110000102210000100
1011000001200221000001101010010110000000110000100
10?1510???????3??????????????1?1??????0?010000100
© 2014 The Linnean Society of London, Zoological Journal of the Linnean Society, 2014, 170, 710–734