Thursday, April 30, 2015

[Paleontology • 2015] Yi qi • A Bizarre Jurassic Maniraptoran Theropod with preserved Evidence of Membranous Wings


Yi qi | ‘ee chee’
Xu, Zheng, Sullivan, Wang, Xing, Wang, Zhang, O’Connor, Zhang & Pan, 2015

A farmer first spotted the dinosaur fossil in the Tiaojishan Formation of Hebei Province, China, dating to the Middle–Upper Jurassic period, or about 160 million years ago. The dinosaur is a member of a group of theropods (mostly carnivorous dinosaurs) called Scansoriopterygidae.
photo: Zang Hailong

The wings of birds and their closest theropod relatives share a uniform fundamental architecture, with pinnate flight feathers as the key component. Here we report a new scansoriopterygid theropod, Yi qi gen. et sp. nov., based on a new specimen from the Middle–Upper Jurassic period Tiaojishan Formation of Hebei Province, China. Yi is nested phylogenetically among winged theropods but has large stiff filamentous feathers of an unusual type on both the forelimb and hindlimb. However, the filamentous feathers of Yi resemble pinnate feathers in bearing morphologically diverse melanosomes. Most surprisingly, Yi has a long rod-like bone extending from each wrist, and patches of membranous tissue preserved between the rod-like bones and the manual digits. Analogous features are unknown in any dinosaur but occur in various flying and gliding tetrapods, suggesting the intriguing possibility that Yi had membranous aerodynamic surfaces totally different from the archetypal feathered wings of birds and their closest relatives. Documentation of the unique forelimbs of Yi greatly increases the morphological disparity known to exist among dinosaurs, and highlights the extraordinary breadth and richness of the evolutionary experimentation that took place close to the origin of birds.


The dinosaur would have sported a robust skull with a short snout
photo: Zang Hailong

Figure 1: Yi qi holotype (STM 31-2).
a, b, Photograph (a) and line drawing (b) of specimen; c, skull and mandible in lateral view; d, premaxillary tooth in lateral view; e, left manus; f, styliform elements (the distally unexposed left styliform element articulates with the wrist, and the orientation of the right styliform element implies a similar relationship to the carpus even though its proximal part is missing). Light and dark grey shading indicates feathers and membranous tissues, respectively. an, angular; cv, cervical vertebrae; d, dentary; dr, dorsal ribs; emf, external mandibular fenestra; en, external naris; f, frontal; lf, left femur; lh, left humerus; lmd2–4, left manual digits 2–„4; lmt, left metatarsals; lr, left radius; ls, left scapula; lse, left styliform element; lu, left ulna; mb, mandible; mcII–IV, metacarpals II–IV; n, nasal; or, orbit; p, parietal; phII1 to IV4, phalanges II‐1 to IV‐4; pma, premaxilla; rmd2–4, right manual digits 2–„4; rf, right femur; rfi, right fibula; rh, right humerus; rmc, right metacarpals; rmt, right metatarsals; rr, right radius; rse, right styliform element; rt, right tibiotarsus; ru, right ulna; sk, skull. Scale bar, 2 cm.


Figure 3: Simplified coelurosaurian phylogeny showing the recovered position of Yi.
The skeletal silhouette and two possible alternative planform reconstructions of Yi highlight the proportionally long and robust forelimbs and large leg feathers that Yi shares with other basal paravian theropods, indicating the presence of aerial capability, and the inferred membranous wings, a feature unique among known paravians but seen in most other gliding or flying tetrapods. Various uncertainties, such as how the styliform element is oriented and whether membranous tissue is present lateral to the trunk as in most volant tetrapods, imply that a variety of reconstructions of the aerodynamic apparatus of Yi are currently plausible (see Supplementary Information for additional possible reconstructions).



Theropoda Marsh, 1881

Maniraptora Gauthier, 1986

Scansoriopterygidae Czerkas et Yuan, 2002

Yi qi gen. et sp. nov.

Etymology. The generic and specific names are derived from Mandarin Yi (wing) and qi (strange), respectively, referring to the bizarre wings of this animal. The intended pronunciation of the name is roughly “ee chee”.

Holotype. STM 31-2 (housed at the Shandong Tianyu Museum of Nature), an articulated partial skeleton with associated soft tissue preserved on a slab and counter slab. The specimen was collected by a local farmer, but its provenance and authenticity have been confirmed by multiple lines of evidence including sedimentology, taphonomy and computed tomography (CT) data.

Locality and horizon. Mutoudeng, Qinglong County, Hebei Province, China. Tiaojishan Formation, Callovian–Oxfordian stage. On the basis of the provenance of the specimen, Yi qi is a member of the Daohugou (or Yanliao) Biota.

Preserved features of the "winged" dinosaur fossil reveal feathers over the neck (not shown), along the humerus (b) and along the humerus and ulna (c). The fossil also showed soft tissue and feathers along the right forelimb and hindlimb.
photo: Zang Hailong | doi: 10.1038/nature14423




Xing Xu, Xiaoting Zheng, Corwin Sullivan, Xiaoli Wang, Lida Xing, Yan Wang, Xiaomei Zhang, Jingmai K. O’Connor, Fucheng Zhang and Yanhong Pan. 2015. A Bizarre Jurassic Maniraptoran Theropod with preserved Evidence of Membranous Wings.
Nature. doi: 10.1038/nature14423

In Photos: Bizarre 'Bat Dinosaur' Discovered in China https://shar.es/1pAfJo  @LiveScience
Chinese Dinosaur Had Bat-Like Wings and Feathers http://on.natgeo.com/1JC8rKd via @ngphenomena
Is it a bird? Is it a bat? Meet Yi qi, the dinosaur that is sort of both http://gu.com/p/48x46/stw
Yi qi by Sheather888 http://sheather888.deviantart.com/art/Yi-qi-529971619

Tuesday, April 28, 2015

[Paleontology • 2015] Chilesaurus diegosuarezi • An Enigmatic Plant-eating Theropod from the Late Jurassic period of Chile


Chilesaurus diegosuarezi 
Novas, Salgado, Suárez, Agnolín, Ezcurra, Chimento, de la Cruz, Isasi, Vargas & Rubilar-Rogers, 2015


Figure 1: Skeletal anatomy of Chilesaurus diegosuarezi gen. et sp. nov.


Theropod dinosaurs were the dominant predators in most Mesozoic era terrestrial ecosystems. Early theropod evolution is currently interpreted as the diversification of various carnivorous and cursorial taxa, whereas the acquisition of herbivorism, together with the secondary loss of cursorial adaptations, occurred much later among advanced coelurosaurian theropods. A new, bizarre herbivorous basal tetanuran from the Upper Jurassic of Chile challenges this conception. The new dinosaur was discovered at Aysén, a fossil locality in the Upper Jurassic Toqui Formation of southern Chile (General Carrera Lake). The site yielded abundant and exquisitely preserved three-dimensional skeletons of small archosaurs. Several articulated individuals of Chilesaurus at different ontogenetic stages have been collected, as well as less abundant basal crocodyliforms, and fragmentary remains of sauropod dinosaurs (diplodocids and titanosaurians).


Dental fossils show that Chilesaurus diegosuarezi did not have sharp, bladed teeth as its relative T. rex did. Here is a side view of its right jaw and teeth.
 (Photo: Fernando Novas)



Theropoda Marsh, 1881

Tetanurae Gauthier, 1986

Chilesaurus diegosuarezi gen. et sp. nov.

Etymology. In reference to Chile, and honoring Diego Suárez, who at the age of 7, discovered the first bone remains in the Toqui Formation.

Locality and horizon. Central Patagonian Cordillera, Aysén (Chile; approximately 46° S); Toqui Formation, Tithonian, latest Jurassic.







Chilesaurus diegosuarezihas characteristics of three different dinosaur groups. Its pubic bone points backward like that of an ornithischian dinosaur, perhaps because it provided the gut more surface area with which to digest plant matter, the researchers said. In most carnivorous dinosaurs, the pubic bone points downward or slightly forward, Carr said.
(Image: Gabriel Lío)




Excavating a Chilesaurus skeleton in beds of the Toqui Formation, Southern Andes, Chile.
At first glance, C. diegosuarezi looks like a perplexing mix of different dinosaurs. But "I think what we're really seeing are the expression of limited options that dinosaurs have when they're herbivores," Carr said. "When you take a meat-eating body and you evolve it into an herbivore, there's only so many options that are available."
(photo: Fernando Novas)



Fernando E. Novas, Leonardo Salgado, Manuel Suárez, Federico L. Agnolín, Martín D. Ezcurra, Nicolás R. Chimento, Rita de la Cruz, Marcelo P. Isasi, Alexander O. Vargas and David Rubilar-Rogers. 2015. An Enigmatic Plant-eating Theropod from the Late Jurassic period of Chile. Nature. (2015) doi: 10.1038/nature14307

 Chilesaurus, a new raptor-like dinosaur with a vegetarian diet. http://po.st/662q2D @SmithsonianMag  

'Bizarre' Jurassic dinosaur discovered in remarkable new find http://gu.com/p/47q7h/stw
7-Year-Old Boy Discovers dinosaur  https://shar.es/1pd7Bn  @LiveScience


Monday, April 27, 2015

[Herpetology • 2015] Pseudophilautus dilmah | Dilmah Shrub Frog | Dilmah panduru madiya • A New Species of Shrub Frog (Anura: Rhacophoridae) from A Threatened Habitat Loolkandura in Sri Lanka


Dilmah Shrub Frog | Dilmah panduru madiya 
Pseudophilautus dilmah
Wickramasinghe, Bandara, Vidanapathirana, Tennakoon, Samarakoon & Wickramasinghe, 2015

Abstract

A new species of shrub frog Pseudophilautus dilmah is described from the Central Hills of Sri Lanka. This unique species is distinguished from all the other congeners from a combination of characters; snout rounded in lateral aspect, bluntly pointed in dorsal and ventral aspect, canthus rostralis rounded, vomerine teeth, lingual papilla and nuptial pads absent, dermal fringe distinct on inside of fingers III and IV, small blunt tubercles on metacarpal and ulnar folds, toes basally webbed, interorbital area smooth, upper eyelid prominent tubercles present, anterior and posterior dorsum without horny spinules but tubercles present, upper part of flank weakly granular, supratympanic fold distinct, prominent small calcar present at the distal end of the tibia, throat granular, chest and belly coarsely granular. Based on comparison of 16s rRNA gene we also show that the species is genetically distinct from other members of Pseudophilautus for which gene sequences are available. The high rate of deforestation and anthropogenic activities threaten this population in its natural habitat.

Keywords: Amphibian, biodiversity hotspot, Dilmah Shrub Frog, new taxa, Pseudophilautus dilmah.



Etymology: The species epithet dilmah is named after Dilmah Conservation [facebook.com/DilmahConservation], for its dedicated efforts to biodiversity conservation on the Island. Dilmah is treated as an invariable noun in apposition to the generic name.

Suggested vernacular names: Dilmah panduru madiya, and Dilmah Shrub Frog in Sinhala, and English respectively.


DISCUSSION
Pseudophilautus dilmah sp. nov., appears to be more resembling to P. bambaradeniyai, (Fig. 2) than to any other species of the same genus. But considering molecular evidences P. bambaradeniyai has been placed in a well separated clade with P. frankensbergi (Meegaskumbura & Manamendra-Arachchi 2005) with a pairwise genetic distance of 10%, which suggests a species level divergence. Although they were both found from the Central Hills they are allopatric. Loolkandura the type locality of P. dilmah sp. nov., is positioned towards the northern tip of the Central Hills where as Peak Wilderness the type locality of P. bambaradeniyai, and the only locality it is found in, is positioned towards south-west of Loolkandura (Fig. 1).

Although P. dilmah sp. nov., is genetically most closest to P. hankeni and P. schmarda, with genetic
distances of 1.6% and 1.9%, respectively, the species is morphologically distinct and can be separated by the characters mentioned in the comparison. Furthermore P. hankeni is distributed in the Knuckles massif which is geographically well separated, and although P. schmarda is distributed in the Central Hills they are allopatric (Fig. 1). Although 3% genetic distance is a good indication

Vences et al. (2005) mention that interspecies genetic distances could be from 1% to 10% and allopatric species are known with less than 3% differences. The pairwise distance for P. pleurotaenia (Boulenger 1904) and P. hoipolloi (Manamendra-Arachchi & Pethiyagoda 2005), for P. asankai (Manamendra-Arachchi & Pethiyagoda 2005) and P. hoffmanni (Meegaskumbura & Manamendra-Arachchi 2005), for P. decoris and P. mittermeieri, were 0.5%, 1%, and 1.4%, respectively. All of which are considered valid morphologically yet have a lower genetic distance than 1.6% for P. dilmah and P. hankeni, and 1.9% for P. dilmah and P. schmarda, hence our current genetic distances from its sister taxa suggests species level divergence.




Wickramasinghe, L.J.M., I.N. Bandara, D.R. Vidanapathirana, K.H. Tennakoon, S.R. Samarakoon & N. Wickramasinghe. 2015. Pseudophilautus dilmah, A New Species of Shrub Frog (Amphibia: Anura: Rhacophoridae) from A Threatened Habitat Loolkandura in Sri Lanka. Journal of Threatened Taxa. 7(5): 7089–7110. DOI: 10.11609/JoTT.o3501.7089-110


[Herpetology • 2015] Rhacophorus indonesiensis | Katak Pohon Totol • A New Species of Tree Frog Genus Rhacophorus (Amphibia, Anura) from Sumatra, Indonesia


Rhacophorus indonesiensis Hamidy & Kurniati, 2015
Adult male paratype MZB Amph 21847 and a non-vouchered female from Birun, showing nocturnal coloration
photo: Mediyansyah || DOI: 10.11646/zootaxa.3947.1.3

Abstract
A small-sized tree frog of the genus Rhacophorus is described on the basis of 18 specimens collected from three different localities on Sumatra Island, Indonesia. Rhacophorus indonesiensis sp. nov. is divergent from all other Rhacophorus species genetically and morphologically. The new species is distinguished from its congeners by a combination of: the presence of black spots on the ventral surfaces of the hand and foot webbing, an absence of vomerine teeth, a venter with a white kite-shaped marking, raised white spots on the dorsum or on the head, and a reddish brown dorsum with irregular dark brown blotches and distinct black dots. With the addition of this new species, fifteen species of Rhacophorus are now known from Sumatra, the highest number of species of this genus in the Sundaland region. However, with the increasing conversion of forest to oil palm cultivation or mining, the possibility of the extinction of newly described or as yet undiscovered species is of great concern.

Key words: Tree frog, Sundaland, pond-breeding, elephant wallow

 Rhacophorus indonesiensis | Katak Pohon Totol



Hamidy, Amir & Hellen Kurniati. 2015. A New Species of Tree Frog Genus Rhacophorus from Sumatra, Indonesia (Amphibia, Anura).
Zootaxa. 3947(1): 49-66. DOI: 10.11646/zootaxa.3947.1.3
ResearchGate.net/publication/274899162_A_new_species_of_tree_frog_genus_Rhacophorus_from_Sumatra_Indonesia_(Amphibia_Anura)


Sunday, April 26, 2015

[Herpetology • 2015] Gegeneophis tejaswini • A New Species of Indian Caecilian Highlights Challenges for Species Delimitation within Gegeneophis Peters, 1879 (Gymnophiona: Indotyphlidae)


Gegeneophis tejaswini 
Kotharambath, Wilkinson, Oommen & Gower, 2015

Abstract

A new species of indotyphlid caecilian amphibian, Gegeneophis tejaswini sp. nov., is described based on eight specimens from lowlands of the most northerly district of the state of Kerala in the southern part of the Western Ghats region, India. This species is distinguished from all other Gegeneophis in annulation characters and genetics (> 6% different from most similar nominal species for 883 base pairs of mitochondrial 12S and 16S rRNA gene sequence data). The high degree of morphological similarity of G. krishni, G. mhadeiensis and the new species underlines that, for some Gegeneophis, larger samples and/or new characters will be needed to further advance the taxonomy of this genus.

Keywords: caecilians, herpetology, India, taxonomy, Western Ghats


Kotharambath, Ramachandran, Mark Wilkinson, V. Oommen & David J. Gower. 2015. A New Species of Indian Caecilian Highlights Challenges for Species Delimitation within Gegeneophis Peters, 1879 (Amphibia: Gymnophiona: Indotyphlidae).
Zootaxa. 3948(1): 60–70. DOI: 10.11646/zootaxa.3948.1.4

[Herpetology • 2015] A Phylogeny of the Only Ground-dwelling Radiation of Cyrtodactylus (Squamata, Gekkonidae): Diversification of Geckoella across peninsular India and Sri Lanka

Fig. 1. Maximum likelihood phylogeny (ND2, RAG1, PDC) of Geckoella, with representative photographs of Geckoella species and a map of peninsular India and Sri Lanka showing sample localities (referenced in Table 1). Outgroups not shown (see Fig. S1 for complete tree); node support indicated by circles, solid fill = high support (ML bootstrap P75, Bayesian PP P 0.95), light fill = support only from Bayesian analyses (Bayesian PP P 0.95, ML bootstrap <75). Sample localities (number) follow the taxa labels.
Photographs of each species complex are approximately scaled by their maximum snout-vent length (Smith, 1935; Bauer and Giri, 2004; Somaweera and Somaweera, 2009). Colored branches and locality labels on the map indicate dry zone and wet zone clade membership. | DOI: 10.1016/j.ympev.2014.09.016

Abstract
The subgenus Geckoella, the only ground-dwelling radiation within Cyrtodactylus, closely overlaps in distribution with brookii group Hemidactylus in peninsular India and Sri Lanka. Both groups have Oligocene origins, the latter with over thrice as many described species. The striking difference in species richness led us to believe that Geckoella diversity is underestimated, and we sampled for Geckoella across peninsular India. A multi-locus phylogeny reveals Geckoella diversity is hugely underestimated, with at least seven undescribed species, doubling previously known richness. Strikingly, the new species correspond to cryptic lineages within described Indian species (complexes); a number of these endemic lineages from the hills of peninsular India outside the Western Ghats, highlighting the undocumented diversity of the Indian dry zone. The Geckoella phylogeny demonstrates deep splits between the Indian species and Sri Lankan G. triedrus, and between Indian dry and wet zone clades, dating back to the late Oligocene. Geckoella and brookii group Hemidactylus show contrasting diversification patterns. Geckoella shows signals of niche conservatism and appears to have retained its ancestral forest habitat. The late Miocene burst in speciation in Geckoella may be linked to the expansion of rain forests during the mid-Miocene climatic optimum and subsequent fragmentation with increasing late Miocene aridification.

Keywords: Mid-Miocene climatic optimum; Aridification; Cryptic species; Historical biogeography


Highlights
• Species diversity vastly underestimated – 7 potentially new Geckoella from hills of peninsular India.
• Geckoella and brookii group Hemidactylus show contrasting historical diversification in peninsular India and Sri Lanka.
• Signals of niche conservatism in Geckoella, retention of terrestrial habit and forest habitat.
• Late Miocene diversification may be linked to mid-Miocene forest expansion and late Miocene aridification.


Ishan Agarwal and K. Praveen Karanth. 2015. A Phylogeny of the Only Ground-dwelling Radiation of Cyrtodactylus (Squamata, Gekkonidae): Diversification of Geckoella across peninsular India and Sri Lanka. Molecular Phylogenetics and Evolution. 82(A); 193–199. DOI: 10.1016/j.ympev.2014.09.016

Friday, April 24, 2015

[Paleontology • 2015] Gorgetosuchus pekinensis • A New Aetosaur (Archosauria, Suchia) from the Upper Triassic Pekin Formation, Deep River Basin, North Carolina, U.S.A., and its Implications for early Aetosaur Evolution




ABSTRACT 
Aetosaurs are an extinct clade of quadrupedal, heavily armored archosaurs that had a worldwide distribution during the Late Triassic. Aetosaur fossils from the Upper Triassic Pekin Formation in the Deep River Basin of North Carolina (U.S.A.) consist primarily of isolated osteoderms and, rarely, more associated material. Here we describe a new genus and species, Gorgetosuchus pekinensis, based on an associated incomplete anterior carapace, consisting of a total of 19 nearly complete paramedian and lateral osteoderms from the first 10 rows of armor as well as some associated fragments. An important feature of Gorgetosuchus is that an articulated fifth row of cervical osteoderms almost encloses the neck, with prominent spines on both the dorsal and lateral osteoderms. This is a novel configuration among aetosaurs. Otherwise, NCSM 21723 preserves a mosaic of character states found in Longosuchus, Lucasuchus, or both taxa while simultaneously preserving several more plesiomorphic character states, such as cervical osteoderms that are wider than long. Our reevaluation of other Pekin Formation specimens that various authors have assigned to Desmatosuchus, Longosuchus, or Lucasuchus confirms that some possess characteristics of Lucasuchus, whereas others are not generically determinate. Incorporating Gorgetosuchus into existing phylogenies of aetosaurs results in a reshuffling of basal aetosaur relationships, but a variety of analyses consistently place Gorgetosuchus as a basal desmatosuchine. Using current taxonomic practices, there are at least three aetosaur genera in the Pekin Formation: Lucasuchus, Coahomasuchus, and Gorgetosuchus




Andrew B. Heckert, Vincent P. Schneider, Nicholas C Fraser and Richard A. Webb. 2015. A New Aetosaur (Archosauria, Suchia) from the Upper Triassic Pekin Formation, Deep River Basin, North Carolina, U.S.A., and its Implications for early Aetosaur Evolution. Journal of Vertebrate Paleontology. 35(1). DOI: 10.1080/02724634.2014.881831


[Paleontology • 2015] Wangosaurus brevirostris • A New Pistosauroid (Reptilia, Sauropterygia) from the late Ladinian Xingyi Marine Reptile Level, southwestern China


Wangosaurus brevirostris
Ma, Jiang, Rieppel, Motani & Tintori, 2015


Abstract

Sauropterygia is a diverse group of Mesozoic marine reptiles that includes the Plesiosauria, one of the most successful clades from the Jurassic to the Cretaceous. The body plan of the Plesiosauria differs from that of basal sauropterygians by adaptations for life in the open ocean, as expressed by the propulsive, paddle-like limbs (Storrs, 1993; Sato et al., 2010; Benson et al., 2012). Triassic pistosauroids are believed to be important in the search for the origin of Plesiosauria (Rieppel et al., 2002; Sato et al., 2010). Until recently, the sister-group relationship between them was mainly based on cranial information, because of the generally poor preservation of Triassic pistosauroid specimens. Eight genera have been reported so far (Meyer, 1839; Yang, 1959, 1965; Storrs, 1991; Rieppel, 1997, 1998, 1999; Sander et al., 1997; Cheng et al., 2006; Dalla Vecchia, 2006), but some of these are known only from relatively complete cranial material (Augustasaurus Sander et al., 1997; Corosaurus Case, 1936; Cymatosaurus Fritsch, 1894; Pistosaurus Meyer, 1839; Yunguisaurus Cheng et al., 2006), whereas Yunguisaurus remains to date the only taxon represented by a complete skeleton.

Three genera of pistosauroids have been reported from the Triassic marine reptile faunas of southwestern China. Chinchenia sungi Young, 1965, from the upper Middle Triassic of Qingzhen, Guizhou Province, and Kwangsisaurus orientalis Young, 1959, from the upper Lower or lower Middle Triassic of Wuming, Guangxi Province, are both extremely fragmentary and listed as Pistosauroidea incertae sedis (Yang, 1959, 1965; Rieppel, 1999, 2000). Yunguisaurus liae Cheng, Sato, Wu, and Li, 2006, from the late Middle Triassic of Chajiang, Guizhou Province, and Fuyuan, Yunnan Province, is the only one represented by a complete skeleton, which is suggestive of early stages of adaptation towards the plesiosaurian functional style (Cheng et al., 2006; Zhao et al., 2008; Sato et al., 2010, 2014). Thus, more complete material should be described to provide new information that would better resolve the origin of Plesiosauria.

Here, we report a new pistosauroid, Wangosaurus brevirostris, gen. et sp. nov., from the late Middle Triassic of Xingyi, Guizhou Province, which shows a combination of plesiomorphic and derived characters (Fig. 1). Due to the rarity of complete and articulated skeletons of pistosauroids, and the presence of enough unique characters gleaned from the dorsal view of this specimen to establish a new genus, we here provide a preliminary description and phylogenetic analysis.







Le-Tian Ma, Da-Yong Jiang, Olivier Rieppel, Ryosuke Motani and Andrea Tintori. 2015. A New Pistosauroid (Reptilia, Sauropterygia) from the late Ladinian Xingyi Marine Reptile Level, southwestern China. Journal of Vertebrate Paleontology. 35(1):1-6.
DOI: 10.1080/02724634.2014.881832


[Paleontology • 2015] Evidence for Sexual Dimorphism in the Plated Dinosaur Stegosaurus mjosi (Ornithischia, Stegosauria) from the Morrison Formation (Upper Jurassic) of Western USA


Fig 4. Hypothetical silhouettes of male and female Stegosaurus mjosi.
  
The wide morph exhibits more overlap between adjacent plates than does the tall morph, leading to a more continuous display surface. Sexual dimorphism in the size and shape and plates might have also occurred with other sexual differences such as sexual dichromatism.


Abstract

Conclusive evidence for sexual dimorphism in non-avian dinosaurs has been elusive. Here it is shown that dimorphism in the shape of the dermal plates of Stegosaurus mjosi (Upper Jurassic, western USA) does not result from non-sex-related individual, interspecific, or ontogenetic variation and is most likely a sexually dimorphic feature. One morph possessed wide, oval plates 45% larger in surface area than the tall, narrow plates of the other morph. Intermediate morphologies are lacking as principal component analysis supports marked size- and shape-based dimorphism. In contrast, many non-sex-related individual variations are expected to show intermediate morphologies. Taphonomy of a new quarry in Montana (JRDI 5ES Quarry) shows that at least five individuals were buried in a single horizon and were not brought together by water or scavenger transportation. This new site demonstrates co-existence, and possibly suggests sociality, between two morphs that only show dimorphism in their plates. Without evidence for niche partitioning, it is unlikely that the two morphs represent different species. Histology of the new specimens in combination with studies on previous specimens indicates that both morphs occur in fully-grown individuals. Therefore, the dimorphism is not a result of ontogenetic change. Furthermore, the two morphs of plates do not simply come from different positions on the back of a single individual. Plates from all positions on the body can be classified as one of the two morphs, and previously discovered, isolated specimens possess only one morph of plates. Based on the seemingly display-oriented morphology of plates, female mate choice was likely the driving evolutionary mechanism rather than male-male competition. Dinosaur ornamentation possibly served similar functions to the ornamentation of modern species. Comparisons to ornamentation involved in sexual selection of extant species, such as the horns of bovids, may be appropriate in predicting the function of some dinosaur ornamentation.


Evan Thomas Saitt. 2015. Evidence for Sexual Dimorphism in the Plated Dinosaur Stegosaurus mjosi (Ornithischia, Stegosauria) from the Morrison Formation (Upper Jurassic) of Western USA.
PLoS ONE.  DOI: 10.1371/journal.pone.0123503

Thursday, April 23, 2015

[Herpetology • 2015] Limnonectes nguyenorum • More of the Same: A Diminutive New Species of the Limnonectes kuhlii complex (Anura: Dicroglossidae) from northern Vietnam

FIGURE 2. Two syntopic species of Limnonectes from northern Vietnam.
Holotype of Limnonectes nguyenorum (VMNH A.2015.1; adult male; SVL = 43.81 mm): (A) dorsal, (B) ventral, (C) plantar view of foot, (D) Palmar view of hand, (E) lateral view of head, (F) magnified view of tubercles on leg (reference in image A). Mature ova from female paratype (VMNH A.2015.3).
Specimen of L. bannaensis from type locality of L. nguyenorum (IEBR A. 2015.38; adult male; SVL = 64.50 mm): (H) lateral view of head, (I) magnified view of tubercles on leg (reference in image J), (J) dorsal, (K) ventral. All specimens imaged as they appear in alcohol.

ABSTRACT 

A new species in the dicroglossid genus Limnonectes known only from Ha Giang province, Vietnam is described. Analysis of DNA sequence data from the mitochondrial 12S and 16S gene regions places the species within the Limnonectes kuhlii Complex and demonstrates it to be the sister taxon to an Indochinese clade containing L. isanensis, L. jarujini, L. megastomias, and L. taylori. The new species occurs in syntopy with L. bannaensis. Both molecular and morphological data support the recognition of this lineage as a new species. Notably, the relatively diminutive size of this species distinguishes Limnonectes nguyenorum sp. nov. from all other members of the L. kuhlii Complex.

Keywords: dicroglossid, fanged frog, Limnonectes nguyenorum sp. nov., mitochondrial DNA, morphology, species complex


Distribution and ecology. Based on the specimens examined, Limnonectes nguyenorum is only known from Vi Xuyen District in northwestern Ha Giang Province, northern Vietnam (Fig. 3). As with other members of the L. kuhii Complex, L. nguyenorum is found along streams in submontane evergreen forests (Fig. 4). The new species seems to occur at elevations approximately between 600 and 900 m, corresponding generally to the transition between lowland and montane forests. Based upon the presence of gravid females of both L. nguyenorum and L. bannaensis during collecting events, it is possible that these species breed at similar times and under similar
conditions.

Etymology. The specific name, nguyenorum, is the plural possessive form of the family name Nguyen. This species is named in honor of two herpetologists who have contributed greatly to our understanding of Vietnamese herpetology and biodiversity, Truong Quang Nguyen and Tao Thien Nguyen. It is rare to find siblings working together in herpetological research, and more so to find brothers as productive as these. We commend them for their efforts and recognize that without them this and many other amphibians and reptiles in Vietnam would remain undescribed.


David S McLeod, Scuyler Kurlbaum and Ngoc Van Hoang. 2015. More of the Same: A Diminutive New Species of the Limnonectes kuhlii complex from northern Vietnam (Anura: Dicroglossidae). Zootaxa. 3947(2):201-214. DOI: 10.11646/zootaxa.3947.2.4

David S. McLeod Lab at James Madison University: facebook.com/787110321326774/photos/823126644391808

Wednesday, April 22, 2015

[Herpetology • 2015] Isanophis gen. nov. • On the Taxonomic Status of the Thai Endemic Freshwater Snake Parahelicops boonsongi, with the Erection of A New Genus (Squamata: Natricidae)


Isanophis boonsongi (Taylor & Elbel, 1958)
 
งูลายสอหมอบุญส่ง
 Boomsong’s Stream Snake | 
Isan Keeled Stream Snake
 Isanophides / Isan Gebirgswassernattern

Abstract

Parahelicops boonsongi Taylor & Elbel, 1958 is known from only three specimens from Thailand. It has been placed either in the genus Parahelicops Bourret, 1934, along with Parahelicops annamensis Bourret, 1934, or in the genus Opisthotropis Günther, 1872. We compared its morphological characters with those of P. annamensis and with three other relevant genera, Opisthotropis, Pararhabdophis Bourret, 1934, and Paratapinophis Angel, 1929. Parahelicops boonsongi is phenotypically distinct from Parahelicops annamensis, Opisthotropis, and all other natricine genera. We consequently erect a new genus, Isanophis gen. nov., to accommodate Parahelicops boonsongi.

Keywords: Serpentes, Natricidae, Parahelicops, Parahelicops annamensis, Isanophis gen. nov., Opisthotropis, Pararhabdophis, Paratapinophis

Etymology. The generic nomen Isanophis is derived from the word “Isan”, the Thai name of the north-eastern region of Thailand, and from the Greek word ophis, meaning “snake”. It describes the limited known range of this genus. This generic nomen is masculine in gender.


David, Patrick, Olivier S. G. Pauwels, Truong Q. Nguyen & Gernot Vogel. 2015. On the Taxonomic Status of the Thai Endemic Freshwater Snake Parahelicops boonsongi, with the Erection of A New Genus (Squamata: Natricidae).
Zootaxa. 3948(2): 203–217. DOI: 10.11646/zootaxa.3948.2.3
Taylor, Edward H. & Elbel, Robert E. 1958. Contribution to the Herpetology of Thailand. Univ. Kansas Sci. Bull. 38 (13): 1033-1189 http://biostor.org/reference/999

Tuesday, April 21, 2015

[Ichthyology • 2015] Description of Danio absconditus and Redescription of D. feegradei (Teleostei: Cyprinidae), from the Rakhine Yoma Hotspot in south-western Myanmar


Danio absconditus Kullander & Britz, 2015
Danio feegradei Hora, 1937

Abstract

Danio feegradei Hora is redescribed based on recently collected specimens from small coastal streams on the western slope of the Rakhine Yoma, ranging from the Thade River drainage southward to slightly north of Kyeintali. Danio absconditus, new species, is described from the Kyeintali Chaung and small coastal streams near Gwa, south of the range of D. feegradei. Both species are distinguished from other Danio by the presence of a dark, elongate or round spot at the base of the caudal fin and a cleithral marking composed of a small black spot margined by a much smaller orange spot. Danio feegradei is characterized by the colour pattern, with series of white spots along the otherwise dark side; D. absconditus by about 7-–11 dark vertical bars on the abdominal side. Within Danio, the presence of a complete lateral line, cleithral spot, and 14 circumpeduncular scales is shared with D. dangila and similar species, but these character states may be plesiomorphic as suggested by the shared presence of cleithral spot and complete lateral line in Devario and Betadevario. In other Danio the cleithral spot is absent, the lateral line is short or absent, and the circumpeduncular scale count is lower (10–12). Twenty teleost species are reported from streams on the western slope of the Rakhine Yoma, all probably endemic. The parapatric distribution of D. absconditus and D. feegradei is unique within the genus, and may be partly explained by changes in eustatic sea levels.

Keywords: colour pattern, freshwater fish, morphology, species discrimination, taxonomy




Kullander, Sven O. & Ralf Britz. 2015. Description of Danio absconditus, new species, and Redescription of Danio feegradei (Teleostei: Cyprinidae), from the Rakhine Yoma Hotspot in south-western Myanmar.
Zootaxa. 3948(2): 233–247. DOI: 10.11646/zootaxa.3948.2.5

Monday, April 20, 2015

[Herpetology • 2015] An Integrative Taxonomic Review of the Agamid Genus Bronchocela (Kuhl, 1820) from Peninsular Malaysia with Descriptions of New Montane and Insular Endemics; Bronchocela shenlong & B. rayaensis


Bronchocela shenlong
Grismer, Wood, Lee, Quah, Anuar, Ngadi & Sites, 2015
DOI: 10.11646/zootaxa.3948.1.1

Abstract

An integrative taxonomic analysis is used to identify and describe two new species of the agamid genus Bronchocela (Kuhl) from Peninsular Malaysia: an upland species Bronchocela shenlong sp. nov. from Bukit Larut, Perak in the Bintang Mountain Range and Parit Falls, Cameron Highlands, Pahang in the Titiwangsa Mountain Range and an insular species, Bronchocela rayaensis sp. nov., from Pulau Langkawi, Kedah off the northwest coast on the border with Thailand. Both species are diagnosed from each other and all other species of Bronchocela on the basis of body shape, scale morphology, and color pattern. The analysis also demonstrates the remarkable genetic similarity of B. cristatella (Kuhl) throughout 1120 km of its range from northern Peninsular Malaysia to western Borneo despite its highly variable coloration and pattern. The two new species are appended to a rapidly growing list of newly described lizard species (60 to date) from Peninsular Malaysia tallied within the last decade.

Keywords: Peninsular Malaysia, Integrative taxonomy, Bronchocela, Langkawi Island




The Dragon of the Mountains. Introducing Bronchocela shenlong, a new species of green crested lizard from the highlands of Peninsular Malaysia that was named after one of the great dragons of Chinese mythology. It can be differentiated from its lowland congener B. cristatella by the broad white stripe on the jawline, green tympanum and red stripe along the lower edge of the tail and posterior margin of the thigh
photograph: Evan Quah

Bronchocela shenlong sp. nov.
Sheng Long Green-crested Lizard

Etymology. The specific epithet shenlong is used here to indicate this species’ morphological and ecological similarity to the “Shen Long” or “Spirit Dragon” of Chinese mythology. Shen Long is a wingless, five-toed, azurecolored reptile that resides in mountains and controls the wind, thunder, rain and clouds. As the epithet is used here, shenlong refers to this species’ upland, cloud forest habitat as well as its general dragon-like appearance.

Distribution. Bronchocela shenlong sp. nov. is known only from Bukit Larut, Perak in the Bintang Mountain Range and from Parit Falls, Cameron Highlands, Pahang in the Titiwangsa Mountain Range (Fig. 1).


Bronchocela rayaensis sp. nov., from Pulau Langkawi, Kedah off the northwest coast on the border with Thailand
photo: David Hegner



Bronchocela rayaensis sp. nov.
Gunung Raya Green-crested Lizard
Bronchocela cristatela Zimmerer 2004:87.
Bronchocela cristatella Manthey 2008:49; Lim et al. 2009:23; Grismer 2011:143.

Distribution. Bronchocela rayaensis sp. nov. is confirmed only from Pulau Langkawi, Kedah, Peninsular Malaysia (Fig. 1). However, B. cristatella has been reported from Pulau Singa Besar, a small satellite island off the southern coast of Pulau Langkawi (Grismer 2008; Lim et al. 2009). The specimens on which these reports were based (DWNP 2250, 2997) should be re-examined as they may be B. rayaensis sp. nov.

Etymology. The specific epithet is derived from the Malay word raya meaning “great” and the Latin suffix -ensis meaning “originating in” and refers to this species discovery at the type locality on Gunung Raya.



Grismer, L. L., JR. P. L. Wood, Cheol H. Lee, Evan S. H. Quah, Shahrul Anuar, Ehwan Ngadi & Jack W. Sites, Jr. 2015. An Integrative Taxonomic Review of the Agamid Genus Bronchocela (Kuhl, 1820) from Peninsular Malaysia with Descriptions of New Montane and Insular Endemics. Zootaxa. 3948(1): 1–23. DOI: 10.11646/zootaxa.3948.1.1
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Grismer, L. L., T. M. Youmans, P. L. Wood Jr, A. Ponce, R. Johnson, S. B. Wright, and S. Y. Norsham. 2006. Checklist of the herpetofauna of Pulau Langkawi with taxonomic comments. Hamadryad. 29:15–32.
http://www.bmnh.org/PDFs/Grismer_etal2006.pdf