A new species of Ectenosaurus (Mosasauridae: Plioplatecarpinae) from western Kansas, USA, reveals a novel suite of osteological characters for the genus1

FHSM VP-5515 is a medium-sized russellosaurine mosasaur collected in the 1970s in Logan County, western Kansas, USA. A suite of cranial features are unique to this specimen at the species level. One is a conspicuous lack of a predental rostrum on the premaxilla, whose dentigerous portion is spatula shaped in dorsoventral aspect. Furthermore, the frontal of FHSM VP-5515 exhibits the following unique combination of features: (1) the median dorsal keel absent; (2) straight, long preorbital borders converging anteriorly at 30° from each other; and (3) supraorbital border thick and extensive, clearly separating the prefrontal and the postorbitofrontal above the orbit. The fifth character pertains to the uniquely square outline of the intramandibular joint surface of the splenial, resulting from a robust dorsomedial flange. Finally, hitherto unreported on any mosasaur jaws, a deep notch excavates the dorsal border of the articular immediately posterior to the glenoid fossa. Examination of preexisting Ectenosaurus specimens suggests that this articular notching diagnoses the genus. Based on the unique suite of characteristics including the articular notch, we consequently hypothesize the following for FHSM VP-5515: (1) it is most comparable with the enigmatic russellosaurine Ectenosaurus clidastoides (Merriam, 1894); and (2) it represents a new species of Ectenosaurus.

A descriptive and comparative neurocranium morphology of Anguilliformes fishes in Taiwan waters

Taiwan is one of the richest in the world in terms of eel fauna. In this study, we examined the osteological and morphological characteristics of eels under order Anguilliformes. Furthermore, we focused on the neurocranium of total of 30 Anguilliformes fishes under family Congridae (10), Muraenesocidae (1), Muraenidae (7), Nemichthyidae (1), Nettastomatidae (2), Ophichthidae (5), Synaphobranchidae (4), which are caught in Taiwanese waters. This paper shows the results of a comparative study on osteological characters of the neurocranium including the ratio of seven length characters using its NCL (neurocranium length), NCW (neurocranium width), OBL (orbit length), MFW (maximum frontal width), NCDB (neurocranium depth at basisphenoid), PEVW (premaxilla-ethmovomer width) and mPOBL (mid pre-orbital length), and 20 morphological diagnostic characters for 30 eel species. Results shows that species under family Nemichthyidae and Nettastomatidae have the highest values on the ratio of NCL/MFW, NCL/NCDB, and NCW/mPOBD. In morphological characters, it shows that species of the same family mostly share similar formation of the PEV plate and frontal structure. The usage of the length measurements and morphological diagnostic characters of neurocranium allowed for a more in depth understanding of how similar or different these eels can be. The neurocranial description and morphological characters may prove valuable for identification purposes and might be necessary tool for further studies on the status of order Anguilliformes.

A new genus for the tiny hawk Accipiter superciliosus and semicollared hawk A. collaris (Aves: Accipitridae), with comments on the generic name for the crested goshawk A. trivirgatus and Sulawesi goshawk A. griseiceps

Multiple molecular phylogenetic studies have demonstrated that two Neotropical raptors, tiny hawk Accipiter superciliosus and its sister species semicollared hawk A. collaris, are not closely related to core Accipiter, and that A. superciliosus, at least, possesses osteological characters not replicated in the remainder of the genus. Based on these data, there is a need to recognise their distinctiveness at generic level. However, as recently noted in two global bird checklists, no name is available to accommodate them, so we provide a new nomen here. Furthermore, two Asian accipitrids, crested goshawk A. trivirgatus and its presumed closest relative Sulawesi goshawk A. griseiceps, are also phylogenetically distinctive; in this case the genus-group name Lophospiza is applicable. We also designate type species for two genus-group names (Hieraspiza and Eusparvius) currently in the synonymy of Accipiter, and, as an aid to future workers, we provide a synonymy of the genus Accipiter and a list of species currently included in Accipiter for which published molecular phylogenetic data are apparently lacking.

Osteological characters for the identification of Caribbean columbids

Columbid remains are commonly recovered from Caribbean archaeological and paleontological sites. Identifying specimens to species level is therefore likely to yield a wealth of information concerning species diversity and changes in their distribution over time. Here we examine the metrical data and 42 osteological characters of eight skeletal elements of 80 specimens belonging to 12 species from five genera that represent most of the indigenous taxa of the West Indies. Our new data provide a reliable means for identifying these birds in the Caribbean fossil and subfossil record.

A sheep in wolf's clothing: Elaphe xiphodonta sp. nov. (Squamata, Colubridae) and its possible mimicry to Protobothrops jerdonii

Based on combined morphological and osteological characters and molecular phylogenetics, we describe a new species of the genus Elaphe that was discovered from the south slope of the Qinling Mountains, Shaanxi, China, namely Elaphe xiphodontasp. nov. It is distinguished from the other congeners by a combination of the following characters: dorsal scales in 21-21-17 rows, the medial 11 rows keeled; 202–204 ventral scales, 67–68 subcaudals; two preoculars (including one subpreocular); two postoculars; two anterior temporals, three posterior temporals; reduced numbers of maxillary teeth (9+2) and dentary teeth (12); sharp cutting edges on the posterior or posterolateral surface of the rear maxillary teeth and dentary teeth; dorsal head yellow, three distinct markings on the head and neck; a distinct black labial spot present in supralabials; dorsum yellow, 46–49 complete (or incomplete) large black-edged reddish brown blotches on the body and 12–19 on the tail, two rows of smaller blotches on each ventrolateral side; ventral scales yellow with mottled irregular black blotches, a few irregular small red spots dispersed on the middle of the ventral. Based on molecular phylogenetic analyses, the new species forms the sister taxon to E. zoigeensis. The discovery of this new species increases the number of the recognized species in the genus Elaphe to 17.

Comparative Osteology, Phylogeny and Classification of the Eastern South American Catfish Genus Trichomycterus (Siluriformes: Trichomycteridae)

Trichomycterus has been considered for a long time to be the most problematic genus of the diverse neotropical subfamily Trichomycterinae. Recently, Trichomycterus was restricted to a clade from eastern South America supported by molecular data, but no unique morphological character state was found to distinguish it, making it difficult to allocate new species based on morphology alone. The objectives of this study were to conduct an osteological comparative analysis comprising a large sample of valid species of Trichomycterus, to conduct a total evidence phylogenetic analysis, combining osteological characters and a multigene database, and to propose an intrageneric classification based on the results of the phylogenetic analysis. Fifty-two osteological characters were combined with a multigene molecular data set of 2974 bp for 44 species of Trichomycterus, and 21 outgroups generated a well-supported phylogenetic tree, making it possible to delimit and diagnose intrageneric lineages, of which six subgenera are recognized. The high morphological diversity of osteological structures herein first reported for Trichomycterus from eastern South America is possibly related to some ecological specializations. This study shows that osteological characters combined with molecular data may be useful to consistently delimit and distinguish between trichomycterines, shedding light on the still persistent problems in trichomycterine systematics.

Phylogenetic relationships of the shearwater taxa Puffinus (sensu lato) and Calonectris (Aves: Procellariiformes: Procellariidae) based on osteological characters

Shearwaters are among the most diverse groups of Procellariiformes, and the systematics of genera Calonectris, Ardenna and Puffinus (sensu stricto) is particularly complex. Here we present the first morphology-based phylogenetic hypothesis for the group, using 104 osteological characters (23 continuous and 81 discrete) scored for 20 extant species of shearwaters, representing 62.5% of species currently recognized. Both equal and implied weighting were used for phylogenetic analyses, and the final hypothesis presented herein is the strict consensus of the most stable trees produced by the latter. Calonectris was recovered as monophyletic (Relative Bremer Support = 75), while all other members of shearwaters were included in a single, monophyletic grouping: Puffinus (sensu lato) (RBS = 76). The monophyly of Ardenna, as suggested by all molecular-based hypotheses, was not recovered, whereas a monophyletic Puffinus (sensu stricto) is present within the larger clade. The final hypothesis, wherein shearwaters fall into the sister taxa Calonectris and Puffinus (sensu lato), is consistent with earlier classifications based on osteological evidence.

First data on the structure of the vertebral column in Gobio and Romanogobio species (Actinopterygii, Cypriniformes, Gobionidae) from Ohrid Lake and the Vardar River basin

The validity of four gudgeon species known for the ichthyofauna of North Macedonia has been a matter of different taxonomic disputes (except for Gobio ohridanus Karaman, 1924). Recently, a restoration of the species status was proposed for Gobio balcanicus Dimovski et Grupče, 1977 and Romanogobio banarescui (Dimovski et Grupče, 1974). So far, Romanogobio stankoi (Karaman, 1974), has not been a part of any recent investigation and it is still considered as a junior synonym of Romanogobio elimeius (Kattoulas, Stephanidis et Economidis, 1973) or R. banarescui due to the lack of distinctive morphological characters. The osteological characters in the structure of the vertebral column, have significance to the systematics of the gudgeons, especially in elevation of Romanogobio at the level of genus. To contribute to resolving the taxonomic status in these gudgeon species, the goal of this paper is to identify distinctive characters by presenting and analyzing the structure of their vertebral column. Samples were inspected from the fish collections in the Institute of Biology (G. ohridanus), the Institute of Animal Science (G. balcanicus), and the Macedonian Museum of Natural History (both Romanogobio species). Fish samples were X-rayed as well as cleared and double-stained. Obtained data on the number of vertebrae were presented through the vertebral formula following Naseka (1996). Multiple Correspondence Analysis (MCA) was used to check the interrelation between taxa and the number of vertebrae in all units of the vertebral column. G. balcanicus is distinguished from G. ohridanus mainly in the predorsal and preanal subregion (10 vs. 11 vertebrae and 1 vs. 0 vertebrae, respectively), while R. stankoi distinguishes from R. banarescui by the number of vertebrae in the preanal and postanal subregion (2 vs. 4 vertebrae and 19 vs. 17 vertebrae, respectively). The structure of vertebral column offers distinctive morphological characters for the four gudgeon species from Ohird Lake and the Vardar River basin.

Filling distribution gaps: Two new species of the catfish genus Cambeva from southern Brazilian Atlantic Forest (Siluriformes, Trichomycteridae)

The fauna and flora of the Brazilian Atlantic Forest have been intensively inventoried since the 19th century, but some components of this rich biota are still poorly known, and some areas have been poorly sampled. Recent studies on a rich collection of mountain catfishes of the genus Cambeva have revealed a high diversity of species still undescribed in the region. Here we provide formal descriptions for two of these species, found in areas inserted in a broad gap of the presently known genus distribution. The first one is endemic to small coastal river basins of Santa Catarina state, southern Brazil; it is tentatively placed in an intrageneric clade, also including C. castroi, C. davisi, C. guareiensis and C. zonata, by all sharing the presence of a flat small process on the dorsal margin of the quadrate, laterally overlapping metapterygoid and situated just posterior to the syncondrial joint between the metapterygoid and the quadrate. Phylogenetic relationships of the second new species, endemic to the Rio Itajaí-Mirim basin, are still obscure, but it shares a derived morphology of the mesethmoid with some species of the C. balios group. Although species of Cambeva have little external morphological variation when compared to other trichomycterine groups, the present study once more shows the importance of recording and using osteological characters to diagnose externally similar trichomycterine species.