Specimens of Hypsilurus spp. corresponding to sequences deposited on GenBank were re-examined. The voucher specimens relating to GenBank sequences were tracked down and their species status confirmed. Sequences reported in earlier publication as H. “bruijnii” and H. “nigrigularis” turned out to be those of H. magnus and H. schultzewestrumi instead. Further confusion surrounded specimens of H. modestus, H. dilophus and H. papuensis. Based on these results a new phylogenetic tree was constructed and the genus name Lophosaurus Fitzinger, 1843 was resurrected.

Hypsilurus , resurrection of Lophosaurus, Lophosaurus dilophus comb. n., Lophosaurus boydii comb. n., Lophosaurus spinipes comb. n.

The Melanesian-Australian agamid genus Hypsilurus currently contains 20 species of which the majority (14 species) occurs on the main island of New Guinea (Manthey and Denzer 2006; Kraus and Myers 2012). Two species are endemic to Australia and several species inhabit the Bismarck Archipelago, Solomon Islands and d’Entrecasteaux Archipelago to the East, Aru Islands to the Southwest and Palau Islands to the North of New Guinea as well as most New Guinean offshore islands. The species with the widest distribution – and most probably the commonest species – is H. modestus which occurs on most of the before mentioned islands apart from the Solomons and Palau. Hypsilurus dilophus shows a similarly wide distribution and appears to be common in places where it occurs (Manthey and Denzer 2006).

The phylogeny of the genus Hypsilurus has been investigated within molecular studies concerned with agamid lizards in general by for example Macey et al. (2000a, b), Schulte et al. (2003), Hugall et al. (2008) and Pyron et al. (2013). The phylogenetic studies of both Schulte et al. (2003) and Pyron et al. (2013) result in two clades for Hypsilurus rendering the genus paraphyletic. None of the studies compared the resulting phylogenetic trees to morphology-based taxonomy and consequently did not name individual clades for nomenclatural purposes.

Manthey and Denzer (2006) published a revision of the genus based on morphological characters. They proposed four species groups which can each be identified by a set of characters:

1. godeffroyi group: Hypsilurus godeffroyi Peters, 1867, H. binotatus Meyer, 1874, H. bruijnii Peters & Doria, 1878, H. hikidanus Manthey & Denzer, 2006, H. longii (Macleay, 1877), H. macrolepis Peters, 1872, H. magnus Manthey & Denzer, 2006, H. ornatus Manthey & Denzer, 2006, H. papuensis (Macleay, 1877), H. schoedei (Vogt, 1932), H. schultzewestrumi (Urban, 1999) and H. tenuicephalus Manthey & Denzer, 2006. This group also includes the recently described H. capreolatus Kraus & Myers, 2012.

2. dilophus group comprising Hypsilurus dilophus (Duméril & Bibron, 1837), H. boydii (Macleay, 1884) and H. spinipes (A. Duméril in Duméril & Duméril, 1851)

3. nigrigularis group Hypsilurus nigrigularis Meyer, 1874, H. geelvinkianus (Peters & Doria, 1878), and H. auritus Meyer, 1874.

4. Hypsilurus modestus Meyer, 1874 was considered as the sole representative of the modestus group.

Currently GenBank (gb, http://www.ncbi.nlm.nih.gov/genbank/) holds sequences for eight species. However, some specimen identifications and assignments of museum vouchers to their respective sequence have been questioned by Manthey and Denzer (2006) as several of the biomolecular studies preceded the revision of the genus and the material was prone to misidentification. Although our analysis does not include Hypsilurus godeffroyi – there are only two short 12S and 16S rRNA available – we note that the species identification of the specimen and corresponding sequence (gb AB031984; KUZ 45215, Kyoto University, Dept. of Zoology, collected in Irian Jaya, New Guinea) is most probably wrong as H. godeffroyi does not occur on New Guinea. Up to now the species is only known from two museum specimens of unreliable provenance and some bone fragments from Palau Island where the species may be extinct (Crombie and Pregill 1999, Bauer and Watkins-Colwell 2001, Manthey and Denzer 2006). With respect to the species investigated in this paper in particular the determination of Hypsilurus nigrigularis (gb AY133016 and HQ662413; TNHC 52009) and Hypsilurus bruijnii (gb AY133014; AMS R122474) were considered doubtful as both species are presumably only represented by very few specimens in museum collections and earlier descriptions were misleading (Boulenger 1914; de Rooij 1922). Currently H. nigrigularis is known only from its type locality (Rubi, Geelvink Bay) [nowadays Cenderawasih Bay or Teluk Sarera]. H. bruijnii specimens are only known from a few specimens near the type locality in the Arfak Mountains.

In this paper we present the results of our investigation into the correct determination of the museum material and assignment of the corresponding GenBank sequences, followed by a phylogenetic analysis of the identified species and a comparison with our earlier morphological study. Finally, we will briefly discuss nomenclatural consequences of the results.

For specimen identification we compared photographs of preserved specimens with material, figures and descriptions given in Manthey and Denzer (2006). Additionally, curators and collection managers were asked to verify the identification of specimens housed in their museum. Abbreviations for museum collections are as follows: ABTC – Australian Biological Tissue Collection, AMS – Australian Museum Herpetological Collection; ANWC – Australian National Wildlife Collection; BPBM – Bernice Pauahi Bishop Museum, QM – Queensland Museum; SAM – South Australian Museum and TNHC – Texas Natural History Collections. Localities and geographical data for Hypsilurus species were sourced online from OZCAM (Online Zoological Collections of Australian Museums, http://ozcam.ala.org.au) and VertNet (http://vertnet.org).

Gene sequences that have been used in the earlier studies by Pyron et al. (2013), Macey et al. (2000a, b) and Schulte et al. (2003) were retrieved from the Nucleotide database (GenBank) of the National Centre for Biotechnology Information (www.ncbi.nlm.nih.gov/nuccore). GenBank accession numbers are listed in Appendix 1. Museum voucher specimens of Hypsilurus spp. corresponding to GenBank sequences are specified in Table 1. The sequence lengths were typically about 1700 bases (shortest sequence 1696, longest 1720 bases) and comprised the mitochondrial genesND1 (partial CDS), tRNA-Gln, tRNA-Ile, and tRNA-Met (complete sequence), ND2 (complete CDS) tRNA-Trp, tRNA-Ala, tRNA-Asx, tRNA-Cys, and tRNA-Tyr (complete sequence) as well as COI (partial CDS) (see Macey et al. 2000a for further information). In our phylogenetic analysis of 19 amphibolurine species the sequence alignment there were 1292 complete sites, of which 753 were variable and 583 were phylogenetically informative (45.1% of complete sites). We employed SeaView 4.5.4 (Gouy et al. 2010) to evaluate the phylogenetic relationships between Australian amphibolurine lizards and species of the genus Hypsilurus. This program package uses Clustal Omega (Sievers et al. 2011) for the alignment procedure as well as PHYLIP 3.696 / dnapars (Felsenstein 1989) and PhyML 3.1 (Guindon et al. 2010) to calculate most parsimonious (MP) and maximum likelihood (ML) phylogenetic trees, respectively. For non parametric bootstrap analysis of the best tree the number of bootstrap replicates was set to 1000. In PhyML the best tree was found by enabling both nearest neighbour interchange (NNI) and subtree pruning and regrafting (SPR).

Initially material used in earlier studies (Macey et al. 2000a, b; Schulte et al. 2003; Hugall et al. 2008) and studied within this paper was re-determined in accordance with the key provided in Manthey and Denzer (2006). Two species turned out to have been misidentified. The corresponding voucher specimens are depicted in Figure 1. The specimen identified in earlier publications as H. “bruijnii” (gb AY133014; AMS R122474) could be determined as H. magnus (see also Kraus and Myers 2012). The voucher specimen clearly shows characters distinguishing it from H. bruijnii. There are 4 rows of small scales between the infralabialia and enlarged submandibular scales (3 rows in H. bruijnii) plus it possesses several dorsal crossbands (no crossbands in H. bruijnii). The H. “nigrigularis” specimen (gb AY133016; TNHC 52009) could be identified as Hypsilurus schultzewestrumi. The gular region and the sides of the head of the voucher specimen are covered with large plates as it is typical for H. schultzewestrumi (gular scales small in H. nigrigularis).

Figure 1. 

Photographs of re-determined specimens. A: Hypsilurus magnus (AMS R122474, previously identified as H. bruijnii). Please note the number of small scale rows (n=4) between infralabialia and enlarged submandibular scales. Insert: Lateral view of the dorsum showing crossbands. Photos: Cecilie Beatson. B: Hypsilurus schultzewestrumi (TNHC 52009, previously identified as H. nigrigularis). Please note the large gular plates that characterize this species. Photo: Travis LaDuc

Some of the confusion surrounding the identification (or rather misidentification) of Hypsilurus nigrigularis specimens in museum collections most probably resulted from two earlier published figures, both of which did not depict “Gonyocephalus nigrigularis” [= H. nigrigularis] as written in the figure captions. In fact Boulenger (1914: pl.XXVIII, fig. 4) shows H. magnus and AMNH (1972:92) shows a photograph of H. schultzewestrumi instead. To our knowledge the only published figure of a true H. nigrigularis is the photograph of the type specimen in Manthey and Denzer (2006: 9, fig. 6).

The specimen of H. dilophus (gb AF128466; AMS R122449) is currently catalogued as H. magnus (OZCAM). This specimen is also erroneously (pers. comm. F. Kraus) listed in Kraus (2010) as AMS R12249 (sic! =R122449) and identified as H. magnus but citing a differing locality, namely Fogamaiyu instead of Namosado (Southern Highlands District) as given on OZCAM, GenBank and in earlier publications (Hugall et al. 2008, ABTC 46027; Schulte et al. 2003; Macey et al. 2000a). A re-examination of the specimen corroborated its original identification as H. dilophus and the collection locality as Namosado.

Additionally there were inconsistencies with respect to the GenBank sequence of Hypsilurus papuensis (gb AY133017) and its corresponding voucher specimen. In an earlier publication (Schulte et al. 2003; Appendix) the source is given a SAMA tissue sample 12965 (South Australian Museum) referring to a voucher specimen CCA 12965 (s. GenBank record). The abbreviation CCA typically refers to collection numbers by C. Austin (Louisiana State University) according to whom this number is too high for collections he made on New Guinea (pers. comm. C. Austin). Enquiries with the Australian Biological Tissue Collection (ABTC) revealed that the number should actually read AA12965 and that this represents a collection number by A. Allison (BPBM). The most recent and correct number for the tissue sample is ABTC 49747 and the corresponding voucher specimen is deposited under BPBM 24102.

Finally there also exists some confusion around Hypsilurus modestus on the OZCAM online database. Schulte et al. (2003) and we used the sequence gb AY133015 (voucher specimen AMS R115478). This specimen is still registered under its old name „Gonocephalus modestus“. A different sequence (gb AF128464; AMS R122434) was used by Hugall et al. (l.c.) and correctly identified as H. modestus. The online database (OZCAM) however, erroneously (pers. comm. G. Shea) assigns this number to a specimen of H. magnus.

Based on these findings we conducted a phylogenetic analysis the results of which are depicted in Figure 2. Both cladograms (MP and ML) are nearly identical and recover previously published phylogenetic relationships. Our analysis corroborates the rejection of the monotypic genus Caimanops and classification of Caimanops amphiboluroides (Lucas & Frost, 1902) as Diporiphora (Hugall et al. 2008) as well as the classification of Rankinia adelaidensis (Gray, 1841) as Ctenophorus (Melville et al. 2001, Hugall et al. 2008).

Figure 2. 

Phylogenetic analysis of Hypsilurus spp. and some Australian agamid lizards belonging to the subfamily Amphibolurinae. A: Most parsimonious tree (PHYLIP/Dnapars); B: Maximum likelihood tree (PhyML). Branch length scale represents number of substitutions/site. Branch support values are given above or next to the branch. Both trees clearly show that Hypsilurus is paraphyletic and forms two distinct clades.

With respect to species of the genus Hypsilurus both trees clearly support different clades. Our maximum likelihood analysis yields a clade containing the two Australian species Hypsilurus spinipes and H. boydii as well as the wide ranging H. dilophus as a sister group to the other studied Australian Amphibolurinae. The remaining four Melanesian species are well supported in an apparently monophyletic clade but still with well supported branches differentiating between H. modestus and H. magnus, H. papuensis, H. schultzewestrumi. In our parsimony analysis a clade containing Hypsilurus spinipes, H. boydii and H. dilophus is formed that also contains the closely related species Moloch horridus and Chelosania brunnea as a sister group. This clade is nested between the Melanesian species of Hypsilurus and the remaining Australian amphibolurine lizards. The branch supports in our maximum likelihood and parsimony analyses for the Moloch / Chelosania clade are comparatively weak. None of the resulting topologies is sufficiently supported to present a clear case for either phylogenetic position of these two genera. Again, our parsimony analysis produces a node separating the branch containing only H. modestus (100% bootstrap support) from the branch comprising the other Melanesian species of Hypsilurus. In summary the two resulting Hypsilurus clades are well supported by molecular genetics and well-defined by morphology (see Manthey and Denzer 2006) such that their separation into two genera is justified.

First, we would like to note that, if sequences are retrieved from databases or databases are consulted for identifying museum material, it may be necessary and appropriate to re-determine the voucher specimens. Great care has to be taken to ensure correct species identification or otherwise misleading phylogenies are published that do not reflect the true intra- and intergeneric relationships between species in accordance with their morphology based taxonomy. For an in-depth discussion on issues related to GenBank see Federhen (2014).

With respect to Hypsilurus species our analysis corroborates the results of earlier published phylogenetic studies by Schulte et al. 2003, Hugall et al. 2008 and Pyron et al. 2013, where the Australian species (H. boydii and H. spinipes) cluster with H. dilophus, while the Melanesian species H. “bruijnii” (= magnus, see results) and H. “nigrigularis” (=schultzewestrumi, see results) are closely related and form a second clade including H. papuensis; H. modestus is the basal taxon and a sister group to the remaining Melanesian Hypsilurus species. Macey et al. (2000a, b) even considered H. modestus sufficiently genetically different from other Hypsilurus species that they used Arua Doria, 1874 as the genus name. The study by Hugall et al. (2008, included species: H. modestus, H. “bruijnii” (= magnus, see results), H. spinipes, H. boydii, H. dilophus) recovered a clade containing Chelosania and Moloch as well as Hypsilurus spp. that was considered to be the sister taxon to all remaining Australian amphibolurine taxa, Townsend et al. (2011, only Hypsilurus boydii included) found that Chelosania and Moloch constitute a sister taxon to a clade containing all Australian amphibolurine taxa and Hypsilurus. Hugall et al. (l.c.) report two clades with respect to Hypsilurus species; one comprising the H. boydii, H. spinipes and H. dilophus, the other clade contains H. “bruijnii” (= magnus, see results) and H. modestus. Morphologically they also found support for this split in the dentition of the species. While H. boydii, H. spinipes and H. dilophus possess “numerous (15–17) small marginal teeth and tiny anterior pleurodont teeth”, H. “bruijnii” (= magnus, see results) and H. modestus possess “larger marginal teeth and enlarged ‘caniniform’ pleurodont teeth” (Hugall et al. 2008: 354).

Already in the original description of Gonyocephalus (Arua) inornatus [= H. modestus fide Boulenger 1885 and Manthey and Denzer 2006] Doria (1874) noted morphological differences between the subgenus Hypsilurus and the subgenus Arua proposed by him. Doria (l.c.) stated that Arua can easily be distinguish from Hypsilurus: “per la mancanza di grossi scudetti agli angoli della bocca, per un sacco golare poco amplio, per la cresta dorsale inconspicua…” [by missing large scales at the angle of the mouth, by a small gular sac, by an inconspicuous dorsal crest...]. The genus Arua was resurrected by Moody (1980) but unfortunately never published formally. Denzer et al. (1997: 323) treated Arua as a subgenus ad Hypsilurus. Macey et al. (2000) removed H. modestus from its synonymy with Hypsilurus species and placed the species in the genus Arua. It has to be noted that Peters and Doria (1878) and Moody (1980) also considered Hypsilurus geelvinkianus and H. auritus as members of Arua. While H. geelvinkianus is superficially similar to H. modestus, H. auritus is not. Both species have several morphological features in common with H. nigrigularis and were combined in a nigrigularis group by Manthey and Denzer (2006). For lack of material these species have not yet been investigated by molecular biological techniques and it may well turn out that species considered by us as belonging to Hypsilurus are more closely related to Arua, should the latter genus be resurrected in future.

The clade containing H. magnus, H. papuensis and H. schultzewestrumi is supported by morphological data and these species are members of the godeffroyi group as defined by Manthey and Denzer (2006). Common characters are enlarged scales or plates at the angle of the mouth or below the tympanum, a row of enlarged submandibular scales (called submaxillaries by Manthey and Denzer [2006]), a homogeneous dorsal scalation and anterior gular pouch scales larger than posterior gular pouch scales.

The clade containing the species Hypsilurus spinipes, H. boydii and H. dilophus was recognised as a species group by Manthey and Denzer (2006). The group can be characterised morphologically by a heterogeneous dorsal scalation and their short tail length (TL/SVL <2.3 in most cases smaller than 2). In their originals description H. boydii were placed in the genus Tiaris Duméril & Bibron, 1837 and H. dilophus in the genus Lophyrus Duméril, 1805. Tiaris is preoccupied and hence not available (Tiaris Swainson, 1827, Aves: Passeriformes); the same is true for Lophyrus which is preoccupied by Lophyrus Poli, 1791 (Mollusca). Manthey and Denzer (l.c.) showed that Lophosaurus Fitzinger, 1843 is a nomen oblitum preceding Hypsilurus Peters, 1867 and available if H. dilophus is removed from its synonymy with Hypsilurus. Therefore the only name available for nomenclatural purposes for this group of lizards is Lophosaurus Fitzinger, 1843 with H. dilophus as the type species.

We currently consider the clade containing Hypsilurus modestus and all Melanesian species of Hypsilurus (apart from H. dilophus) as monophyletic. We suggest to leave these species in Hypsilurus sensu lato until additional material becomes available and further biomolecular studies can be conducted that include additional species of Hypsilurus s.l. Morphologically Hypsilurus s.l. can be divided into a godeffroyi species group, a nigrigularis species group and the monotypic modestus species group (s. Manthey and Denzer 2006 for definitions). All three groups may turn out to be genera in their own right, in particular further analysis may warrant the resurrection of the genus Arua Doria, 1874 for Hypsilurus modestus. We also consider the clade containing the Australian species Hypsilurus boydii and H. spinipes as well as the Melanesian H. dilophus as monophyletic and propose to resurrect the genus name Lophosaurus Fitzinger, 1843 for this group of agamid lizards. The name is masculine gender and therefore the species epithets remain the same.

We are grateful to Travis LaDuc and David Cannatella (both TNHC), Cecilie Beatson and Ross Sadlier (AMS) as well as Molly Hagemann (BPBM) for providing photographic records of specimens held in their collections. Leanne Wheaton (SAM) tracked down the tissue specimen for H. papuensis and provided vital information regarding the voucher specimen. Chris Austin (Louisiana State University) shared his view on the collection number of H. papuensis; Allen Allison and Molly Hagemann (both BPBM) confirmed the identity and collection data of the voucher specimen. Fred Kraus (University of Michigan) shared his knowledge on H. magnus specimens in the collection of the Australian Museum and confirmed their identification. Glenn Shea (University of Sydney) helped to identify the voucher specimen for H. dilophus and checked the identities of H. modestus specimens held in the Australian Museum. We very much appreciate their help in solving the “mysteries” surrounding some of the specimens used in this study.

Genbank Accession Numbers and corresponding museum specimen data (for Hypsilurus specimens only): Caimanops (=Diporiphora) amphiboluroides (AF128472), Chelosania brunnea (AF128465), Chlamydosaurus kingii (EF090421), Ctenophorus adelaidensis (AF128471), Ctenophorus maculatus (AF375628), Diporiphora winneckei (AY133012), Lophognathus gilberti (AY133019), Moloch horridus (AF128467), Physignathus (=Intellagama) lesueurii (AF128463), Pogona nullarbor (AY133025), Rankinia diemensis (KF791202), Tympanocryptis lineata (AF128475).