Showing posts with label Osteology. Show all posts
Showing posts with label Osteology. Show all posts

Monday, October 5, 2026

[Herpetology • 2026] Calamaria flavicollaris • Integrative Taxonomy reveals A New Species of Calamaria (Squamata: Calamariidae) from the Tenasserim Range, Western Thailand

 

 Calamaria flavicollaris
 Aksornneam, Rujirawan, Yodthong, Pawangkhanant, Sung & Aowphol, 2026
 
Tenasserim Collared Reed Snake | งูพงอ้อบ่วงบาศ ||  DOI: doi.org/10.1163/18759866-bja10102 
 Photographed by Parinya Pawangkhanant

Abstract
A new species of Calamaria is described from the Tenasserim Range, Ratchaburi Province, western Thailand based on morphological and molecular evidence. Calamaria flavicollaris sp. nov. can be distinguished from its congeners by the combination of the following morphological characters: 1) rostral scale wider than high; 2) portion of rostral scale visible from above greater than the half the length of the prefrontal suture; 3) prefrontal length shorter than frontal length, not entering orbit and in contact with first two supralabials; 4) five or six scales surrounding paraparietal scale; 5) preocular and postocular present; 6) four supralabials, the second and third in contact with the eyes; 7) eye diameter smaller than eye-mouth distance; 8) five infralabials, the first pair separating the mental scale from anterior chin shields; 9) seven modified maxillary teeth; 10) 180 ventral scales with three preventral scales; 11) 13 divided subcaudal scales; 12) cloacal plate single; 13) tail relatively short (4.5% of the total length), tapering, gradually to a pointed tail tip; 14) dorsum dark brown with eleven dark longitudinal stripes; 15) ventral surface yellow with a median line of dark flecks on underside of tail; and 16) dark collar followed by yellow ring at nuchal region. Genetically, the new species exhibits a pairwise distance of ≥17.56% from all other congeners based on the mitochondrial cytochrome b gene fragment. Furthermore, we provide cranial osteological description of the new species based on micro-CT scanning. Calamaria flavicollaris sp. nov. is currently known only from the type locality and represents the fourth species of the genus recorded for Thailand. 

Keywords: cranial osteology; herpetofauna; Isthmus of Kra; molecular; reed snake; Southeast Asia


Holotype of Calamaria flavicollaris sp. nov. (ZMKU R 01131) in life. A small figure shows the yellow color on the ventral side of this species 
 Photographed by Parinya Pawangkhanant

Head of  Calamaria flavicollaris sp. nov. (ZMKU R 01131).
A–B lateral view C–D dorsal view E–F ventral view

Holotype of  Calamaria flavicollaris sp. nov. (ZMKU R 01131)
in preservative. A dorsal view B ventral view C lateral view at the midbody D dorsal view of tail E ventral view of tail

Calamaria flavicollaris sp. nov.

Diagnosis. Calamaria flavicollaris sp. nov. can be distinguished from all other congeners by the following combination of characters (Tables 3, 4; Suppl. Table 1): 1) rostral scale wider than high; 2) portion of rostral scale visible from above greater than the half the length of the prefrontal suture; 3) prefrontal length shorter than frontal length, not entering orbit, and in contact first two supralabials; 4) five or six scales surrounding the paraparietal scale; 5) preocular and postocular present; 6) four supralabials, the second and third in contact the eyes; 7) eye diameter smaller than eye-mouth distance; 8) five infralabials, the first pair separating the mental scale from anterior chin shields; 9) seven modified maxillary teeth; 10) 180 ventral scales with three preventral scales; 11) 13 divided subcaudal scales; 12) cloacal plate single; 13) tail relatively short (4.5% of the total length), tapering, gradually to a pointed tail tip; 14) dorsum dark brown with eleven dark longitudinal stripes; 15) ventral surface yellow with a median line of dark flecks on underside of tail; and 16) a dark nuchal collar followed by a yellow ring along neck.

Four Calamaria species in Thailand:
A Calamaria flavicollaris sp. nov. from Suan Phueng District, Ratchaburi Province B C. lumbricoidea from Than To District, Yala Province
C C. schlegeli from Betong District, Yala Province D C. pavimentata from Kaeng Hang Maeo District, Chanthaburi Province 
Photos by Parinya Pawangkhanant (A–C) and Attapol Rujirawan (D)

Etymology. The specific epithet flavicollaris is derived from the Latin words “flavo” (yellow), “collare” (collar or neck), and the suffix “-aris”, which refers to the appearance of the yellow nuchal ring of this species. 
We suggested an English common name “Tenasserim Collared Reed Snake” and the Thai common name “งูพงอ้อบ่วงบาศ” (Ngu Phong O Buang Bat) for this species.


 Akrachai Aksornneam, Attapol Rujirawan, Siriporn Yodthong, Parinya Pawangkhanant, Yik-Hei Sung, and Anchalee Aowphol. 2026. Integrative Taxonomy reveals A New Species of Calamaria (Squamata: Calamariidae) from the Tenasserim Range, Western Thailand.  Contributions to Zoology. 95(4); 366–410. DOI: doi.org/10.1163/18759866-bja10102 [22 Sep 2026]

งูพงอ้อหัวแดง Calamaria schlegeli; 
งูพงอ้อหลากลาย Calamaria lumbricoidea; 
งูพงอ้อท้องเหลือง Calamaria pavimentata

Friday, October 2, 2026

[Ichthyology • 2026] Hypomasticus rectangulatus • A New Species of Hypomasticus (Characiformes: Anostomidae) from the Vila Nova River, State of Amapá, Brazil


Hypomasticus rectangulatus
Ito, Gama, Sabaj & Birindelli, 2026


 Abstract  
A new species of Hypomasticus is described from the Vila Nova River, a left-bank tributary to the lower Amazon in the state of Amapá, Brazil. The new taxon belongs to the Hypomasticus granti group, a clade recently corroborated by molecular phylogenetics, and is diagnosed by a color pattern distinctive among anostomids: midlateral side with dusky rectangular blotch extending from the opercle to near vertical through dorsal-fin origin and followed by three dark oblong (vertically elongated) blotches well separated on posterior half of body, and (in adults) scales in anterior portion of lateral line and flanking rows with a dark spot at their base, forming three longitudinal rows within the dusky rectangular blotch. It further differs from congeners by having 32–34 perforated lateral-line scales and 12 circumpeduncular scale rows. Osteological examination revealed polymorphism in the number of dentary teeth regarding the presence of a fifth tooth, a condition previously observed in other members of the H. granti group. Sexual dimorphism was recorded with males exhibiting hypertrophy of the first pair of ribs, a condition previously unknown within this clade.

Hypomasticus rectangulatus.
(A) IEPA 5637, holotype, 213.3 mm SL and (B) IEPA 5417, paratype, 89.84 mm SL. Brazil, Amapa´ state, municipality of Mazaga˜o, rio Vila Nova. Photos by M. Sabaj. Scale = 1 cm.

Hypomasticus rectangulatus sp. nov. 

Etymology.—The specific epithet rectangulatus is derived from the Latin word meaning rectangular or right-angled, in reference to the distinctive rectangular blotch present on the anterior midlateral region of the body. An adjective.
 

Ian Solon Bortoloci Ito, Cecile de Souza Gama, Mark Henry Sabaj and José Luís Olivan Birindelli. 2026. A New Species of Hypomasticus (Characiformes: Anostomidae) from the Vila Nova River, State of Amapá, Brazil. Ichthyology & Herpetology. 114(3); 507-519. DOI: doi.org/10.1643/i2025102 (22 September 2026)

Wednesday, September 16, 2026

[Paleontology • 2026] Craniomandibular osteology of Dinodontosaurus isiyavamanda sp. nov. (Therapsida: Anomodontia) from the Manda Beds of Tanzania and new support for a younger age for the alleged oldest dinosaurs

 

Dinodontosaurus isiyavamanda
George, Escobar, Moody, Saanane, Day & Larkin, 2026

Life reconstruction by Gabriel Ugueto
 
ABSTRACT 
Fossils from the Manda Beds of Tanzania have greatly informed on the diversity and evolution of Triassic tetrapods, including on what might be the oldest dinosaurs. Here, a new dicynodont taxon from the Manda Beds is described. It lacks key anatomical traits of known dicynodonts from the Manda Beds, as well as the Sino-African genus Shansiodon to which some of this material was previously referred. The new taxon is referred to the otherwise South American Dinodontosaurus based on the diagnostic presence of frontals with “tab-like” anterior processes and a combination of other traits seen in the genus. This Tanzanian material possesses a predominantly bulbous posterior/median palatal ridge of the premaxilla and a midline groove along the temporal bar, among other traits that are absent in the South American Dinodontosaurus material, indicating it represents a distinct species, here named Dinodontosaurus isiyavamanda sp. nov. Phylogenetic analyses conducted with Bayesian estimation and parsimony support the inclusion of this species in Dinodontosaurus. The unique palate of D. isiyavamanda is hypothesized to be related to resource partitioning, representing different adaptations for food processing than coeval dicynodonts. The presence of Dinodontosaurus suggests the mid-to-upper Lifua Member of the Manda Beds is equivalent to the Dinodontosaurus Assemblage Zone of Brazil and the Chañares Formation of Argentina. Consequently, the mid-to-upper Lifua Member, which includes what are possibly the oldest records of dinosaurs globally, can be confidently interpreted as late Ladinian to Carnian in age, supporting recent research questioning its equivalency with the Cynognathus Assemblage Zone of South Africa.


SYSTEMATIC PALEONTOLOGY
SYNAPSIDA Osborn, 1903
THERAPSIDA Broom, 1905

ANOMODONTIA Owen, 1860
DICYNODONTIA Owen, 1859

DICYNODONTOIDEA Olson, 1944
KANNEMEYERIIFORMES Maisch, 2001

DINODONTOSAURUS Romer, 1943
Diodontosaurus Tupí-Caldas, 1936 [nomen suppressum].
Chanaria Cox, 1968.

Type Species––Dinodontosaurus oliveirai Romer, 1943 (=Dicynodon tener Huene, 1935).

Diagnosis––Medium- to large-sized kannemeyeriiform (maximum skull length ca. 40 cm) with the following unique combination of character states: frontals with a “tab-like” median anterior process; postorbital bone with elongate, curved suborbital process; elongate caniniform process sharply offset from zygomatic arch; and hypertrophied tusks present in large individuals (taken from Kammerer & Ordoñez, 2021).


DINODONTOSAURUS ISIYAVAMANDA sp. nov.
Ruhuhuungualasaurus croucheri Larkin, 1994, p. 2.
Shansiodon sp. Surkov and Benton, 2004, p. 627.
Shansiodon sp. Surkov and Benton, 2008, p. 1126.

Diagnosis––Can be distinguished from both Dinodontosaurus brevirostris and Dinodontosaurus tener by a premaxillary posterior/median palatal ridge that expands anteriorly into a wide, bulbous morphology (does not retain the ridge-like morphology throughout its length), and extends further anteriorly than the point of eruption of the tusks; a midline groove extending along the temporal bar from immediately posterior to the pineal foramen to the posterior end of the postparietal; and mandibular rami that diverge more laterally. Can be further distinguished from Dinodontosaurus brevirostris by the lack of a ridge along the anterior surface of the mandibular symphysis. Can be further distinguished from Dinodontosaurus tener by a wider interorbital region and snout, and a pineal foramen that is not completely anterior to the intertemporal bar (i.e., pineal foramen is at the same anteroposterior level as the anterior portion of the bar).

Etymology––From the Manda words ‘isi ya vamanda’ that translate to ‘country of the Wamanda.’ In reference to the Wamanda people, many of whom were crucial to the discovery of the holotype, but whose individual names were not documented and never credited.

two bulky Dinodontosaurus isiyavamanda walking through dense vegetation 
Life reconstruction by Gabriel Ugueto


Hady George, Juan A. Escobar, Edmund R.R. Moody, Charles B. Saanane, Michael O. Day and Nigel R. Larkin. 2026. Craniomandibular osteology of Dinodontosaurus isiyavamanda sp. nov. (Therapsida: Anomodontia) from the Manda Beds of Tanzania and new support for a younger age for the alleged oldest dinosaurs. Journal of Vertebrate Paleontology. e2692542. DOI: doi.org/10.1080/02724634.2026.2692542 [15 Sep 2026]
 

Tuesday, September 15, 2026

[Herpetology • 2026] Lycodon trifasciatus • Neotype Designation for Lycodon aulicus (Linnaeus, 1758) (Squamata: Colubridae) and Description of A New Species from Sri Lanka

 

Lycodon trifasciatus
Amarasinghe, Aththanagoda, Ranasinghe, Vogel & Karunarathna,

 in Amarasinghe, Campbell, Seneviratne, Weerakkody, Mata, Kennedy-Gold, Aththanagoda, Ranasinghe, Vogel et Karunarathna, 2026. 

Abstract
We revisit the systematics of Sri Lankan wolf snakes, historically assigned to Lycodon aulicus and describe a new species using an integrative assessment of external morphology (morphometry, meristics, and hemipenial morphology), osteology (microCT), mitochondrial DNA (cytochrome b), and distributional data. Phylogenetic analyses of the mitochondrial cytochrome b gene recovered the L. aulicus group as a strongly supported monophyletic clade that includes five distinct lineages: (i) a Sri Lankan lineage currently referred to as L. aulicus, (ii) L. flavicollis from India, (iii) L. capucinus from the Sundaland region, (iv) L. zawi from Myanmar, and (v) the Sri Lankan endemic described herein as a new species. In our analyses, the new species is placed close to the Sri Lankan lineage currently identified as L. aulicus and to L. flavicollis, although support for some internal relationships is limited. Because the molecular representation of L. aulicus remains geographically restricted (including only a single sequenced Sri Lankan individual and no sequence data from the neotype locality in southwestern India), broader conclusions about the species boundaries, monophyly, and range-wide structure of L. aulicus should be treated as provisional working hypotheses. We do not attempt a range wide revision of L. aulicus sensu lato; we restrict our taxonomic actions and interpretations to (i) stabilizing name usage via type fixation and (ii) diagnosing the description of an overlooked Sri Lankan tri banded lineage.

 (A) Lycodon aulicus neotype (NHMUK 1904.10.18.5), an adult male from Kannur City in Kerala State, India; © Photo: GV; (B) adult voucher specimen of Lycodon aulicus (in life) from Rambukkana, Sri Lanka (NMSL 2026.09.04/Field No. DMSSK217); © Photo: SK.
 (C) Lycodon trifasciatus sp. nov. paratype (NMSL 2026.09.01/Field No. DMSSK379), an adult male from Udadumbara, Sri Lanka; © Photo: SK; (D) a hatchling of L. trifasciatus sp. nov. (in life) from Kalutara, Sri Lanka (not collected); © Photo: AKAG.

Dorsal, ventral, and lateral head scalation of (A) neotype of L. aulicus (NHMUK 1904.10.18.5; also, lectotype of L. a. oligozonatus) from Cannanore in the Malabar Coast (now Kannur in the Kerala State), (B) holotype of Lycodon trifasciatus sp. nov. (FMNH 165045) from Anamaduwa, Sri Lanka, and (C) topotype of L. capucinus (UIMZ 0121) from Central Java.
 Illustrations by A.A. Thasun Amarasinghe (not to scale).

Lycodon trifasciatus Amarasinghe, Aththanagoda, Ranasinghe, Vogel & Karunarathna, sp. nov.

Diagnosis. Lycodon trifasciatus sp. nov. is distinguished from other congeners by having the following combination of characters (Table 2): adults reach maximum SVL 615 mm; a single preocular; two postoculars; a single loreal scale; divided cloacal plate; nasal scale completely divided by the nostril; preocular in contact with frontal; ventrals 182–184 in 2 males and 192– 195 in 3 females; subcaudals 51–60+ in males and 40–65 in females; 2+3 temporals shorten; nine supralabials with 3rd–5 th in contact with eye; dorsal scale rows 17-17-15; tail length 16.2– 18.1% of total length in males; reddish or dark olive brown dorsum (rarely black) with three (rarely four) white striated crossbands only on the anterior part of the body; crossbands with thickness of 2–4 vertebral scales and 22–28 scales in-between crossbands; 28–33 vertebrate scales between the parietal and first crossband on the body; poorly visible collar mark on the nape; absence of white lip band.


A.A. Thasun Amarasinghe, Patrick D. Campbell, Sampath S. Seneviratne, Sanjaya Weerakkody, Joshua Mata, Stevie R. Kennedy-Gold, Anusha Aththanagoda, Bhanuka Ranasinghe, Gernot Vogel and Suranjan Karunarathna. 2026. Neotype Designation for Lycodon aulicus (Linnaeus, 1758) (Squamata: Colubridae) and Description of A New Species from Sri Lanka. TAPROBANICA. 15(2); DOI: doi.org/10.47605/tapro.v15i2.422

Monday, September 7, 2026

[Ichthyology • 2026] Petulanos jasteri • A New Species of Petulanos (Characiformes: Anostomidae) from the Rio Araguari, Amapá State, Brazil

 

Petulanos jasteri
Birindelli, Lima & Gama, 2026


Abstract
The Neotropical family Anostomidae comprises over 150 valid species, though its true diversity remains underestimated. The genus Petulanos currently includes four species distributed across northern South America, all characterized by upturned mouths, compressed multicuspid dentition, and distinctive color patterns. In this study, we describe Petulanos jasteri, a new species apparently endemic to the rio Araguari, Amapá state, Brazil. Despite hosting extensive protected areas, Amapá remains poorly surveyed, and its ichthyofauna is still insufficiently documented. The new species is readily distinguished from congeners by its color pattern, consisting of three vertically elongated dark blotches on the posterior half of the trunk (without pale margins) combined with eight to ten dark vertical bars. It lacks the horizontal stripes that characterize P. brevior, as well as the rounded blotch above the pectoral fin present in P. intermedius, P. plicatus, and P. spiloclistron, and has 38 or 39 lateral-line scales (vs. 40 to 42 in P. spiloclistron). Osteological characters confirm its assignment to Petulanos, sharing synapomorphies such as four branchiostegal rays, bicuspid symphyseal premaxillary tooth, symplectic with a distinctive triangular ventral lamina, and open cranial fontanel. Petulanos jasteri, new species, is the first species of the genus reported from the rio Araguari. Its discovery emphasizes the underestimated diversity of the Anostomidae and highlights the need for further surveys and integrative studies in poorly explored basins of northern Brazil.

Petulanos jasteri.
(A) Holotype, IEPA 6078, 72.9 mm SL, Amapá, Ferreira Gomes, rio Mutum, tributary to rio Araguari, at Parque Nacional Montanhas do Tumucumaque.
(B) Paratype, ZUEC 14774, 83.7 mm SL, Amapá, Ferreira Gomes, rio Araguari.
(C) Paratype, ANSP 211099 (ex. IEPA 6079), 64.1 mm SL, rio Mutum, tributary to rio Araguari, at Parque Nacional Montanhas do Tumucumaque, photographed alive.
Scale bar = 10 mm. 

Petulanos jasteri, a new species 

Etymology.—The specific name jasteri honors Dr. Christoph Bernhard Jaster, formerly chief of the Tumucumaque National Park and the Amapá National Forest, for having made possible many field expeditions in these Conservation Units for the IEPA Ichthyology team, being a great supporter of basic science and biological surveys at Amapá State.


José L. O. Birindelli, Flávio C. T. Lima, Cecile S. Gama. 2026. New Species of Petulanos (Characiformes, Anostomidae) from the Rio Araguari, Amapá State, Brazil. Ichthyology & Herpetology. 114(3):451-460. DOI: doi.org/10.1643/i2025080 [28 August 2026]

Tuesday, August 11, 2026

[Ichthyology • 2026] Rakthamichthys anchi • A New Species of phreatobitic synbranchid eel (Synbranchiformes: Synbranchidae) from Assam, India

 

Rakthamichthys anchi 
Britz, Pinion, Marak, Velentina & Lokeshwor, 2026 
 

Abstract
Rakthamichthys anchi, a new species of phreatobitic synbranchid is described from wells in a small village in Goalpara District, Assam, Northeast India. It is distinguished from the northeastern Indian R. rongsaw, and the Western Ghats congeners R. roseni, R. digressus, and R. mumba by absence of lateral-line canal pores in the frontal. From R. roseni, R. digressus, and R. mumba, it is further distinguished by more preanal vertebrae (90–100 vs. 76–88 in) and from R. indicus by more vertebrae (159 vs.162–169). It is also distinguished from the Western Ghats species by an uncorrected p-distance of ~15–20% in the barcoding gene. From R. roseni, the only Western Ghats species for which detailed osteological information is available, R. anchi is distinguished by several anatomical characters. The discovery of R. anchi from wells in the same village in which Gitchak nakana Britz et al. [2026] was recently described highlights the presence of a formerly unknown and highly dynamic subterranean habitat: the groundwater aquifers in alluvial deposits in northeast India.

Pisces, swamp eels, groundwater, well, subterranean fishes, micro-CT, skeleton





Ralf BRITZ, Amanda K. PINION, Wimarithy K. MARAK, Kangjam VELENTINA and Yumnam LOKESHWOR. 2026. Rakthamichthys anchi, A New Species of phreatobitic synbranchid eel from Assam.  Zootaxa. 5857(3); 462-482. DOI: doi.org/10.11646/zootaxa.5857.3.3 [2026-07-30]

Thursday, July 9, 2026

[Paleontology • 2024] Cranial Osteology and Paleoneurology of Tarjadia ruthae: An erpetosuchid pseudosuchian from the Triassic Chañares Formation (late Ladinian-?early Carnian) of Argentina

 

Tarjadia ruthae Arcucci & Marsicano, 1998
 
in Desojo, von Baczko, Ezcurra, Fiorelli, Martinelli, ... et Lacerda, 2026. 
Reconstruction: Jorge Blanco
 
Abstract
Tarjadia ruthae is a quadrupedal terrestrial pseudosuchian from the Middle-early Upper Triassic of the Chañares Formation, La Rioja Province, Argentina. Originally, this species was identified as an indeterminate archosaur and later as a doswelliid archosauriform based on very fragmentary specimens characterized by the ornamentation of the skull roof and osteoderms. Additional specimens (including skulls and postcrania) recovered in the last decade show that Tarjadia is an erpetosuchid, an enigmatic pseudosuchian group composed of six species registered in Middle-Upper Triassic continental units of Tanzania, Germany, Scotland, North America, Brazil, and Argentina. Tarjadia ruthae from Argentina and Parringtonia gracilis from Tanzania are the best preserved and more abundant species. Although the monophyly of Erpetosuchidae is well supported, alternative high-level positions within Archosauria have been suggested, such as sister taxon to Crocodylomorpha, Aetosauria, or Ornithosuchidae. In order to improve the knowledge about the erpetosuchids, we performed a detailed description and paleoneurological reconstruction of the skull of Tarjadia ruthae, based on two articulated partial skulls (CRILAR-Pv 478 and CRILAR-Pv 495) and other fragmentary specimens. We analyzed the stratigraphic and geographic occurrence of historical and new specimens of Tarjadia and provided a new emended diagnosis (the same for the genus as for the species, due to monotypy) along with a comparative description of the cranial endocast. The skull of Tarjadia is robust, with a thick and strongly ornamented skull roof, triangular in dorsal view, with concave lateral margins at mid-length that form an abrupt widened posterior region. The external nares are the smallest openings of the skull. The antorbital fossa is deeply excavated and has a small heart-shaped fenestra with both lobes pointing anteriorly. The supratemporal fenestrae are as large and rounded as the orbits, and the infratemporal fenestrae are L-shaped with an extensive excavation along the jugal, quadratojugal and quadrate. The hemimandibles are low, slightly concave on the dentigerous region and strongly convex on the posterior region, conferring them a S-shaped profile in dorsal view. The external mandibular fenestra is small and elliptic, being twice longer than high. The maxillary dentition is restricted to the anterior to mid region of the rostrum. Since the braincase of both specimens is partially damaged, the dorsal surface of the brain could not be entirely reconstructed. As a result, the endocast is anteroposteriorly elongated and seemingly flat, and the cephalic flexure seems to be lower than expected for a suchian. The labyrinth is twice wider than high, the semicircular canals are remarkably straight, and the anterior canal is longer than the posterior one.

Keywords: anatomy, Archosauria, Erpetosuchidae, neuroanatomy, skull

Systematic paleontology
Archosauriformes Gauthier et al., 1988.
Archosauria Cope, 1869 sensu Gauthier & Padian, 1985.
Pseudosuchia von Zittel, 1887–1890 sensu Gauthier & Padian, 1985.

Erpetosuchidae Watson, 1917 sensu Nesbitt & Butler, 2013.

Tarjadia ruthae Arcucci & Marsicano, 1998

Life reconstruction of Tarjadia ruthae by Jorge Blanco.


J. B. Desojo, M. B. von Baczko, M. D. Ezcurra, L. E. Fiorelli, A. G. Martinelli, P. Bona, M. J. Trotteyn and M. Lacerda. 2024. Cranial Osteology and Paleoneurology of Tarjadia ruthae: An erpetosuchid pseudosuchian from the Triassic Chañares Formation (late Ladinian-?early Carnian) of Argentina. The Anatomical Record. DOI: doi.org/10.1002/ar.25382 [23 January 2024]

Friday, June 5, 2026

[Herpetology • 2026] Calotes thailandensis & C. maehongsonensis • Systematics of the Calotes irawadi complex (Squamata: Agamidae) with Two newly described Species from Thailand


Calotes thailandensis 
Prakobkarn, Zug, Tandavanitj & Ngamprasertwong, 2026
 
กิ้งก่ารั้ว, กิ้งก่าหัวแดง  DOI: doi.org/10.3897/zookeys.1281.175455 

Abstract
Two new species of Calotes lizards, Calotes thailandensis sp. nov. and C. maehongsonensis sp. nov., are diagnosed and described from Thailand. These new species are most closely related to C. irawadi and C. wangi, which are members of the C. irawadi complex, supported by phylogenetic analysis of mitochondrial DNA data (ND2 and COI genes) coupled with morphometric and osteological data. Calotes thailandensis sp. nov. and C. maehongsonensis sp. nov. are distinguished from true C. irawadi by having a wider PelvW, but a smaller head size in adult males. In particular, adult males of C. thailandensis sp. nov. obviously differ from both C. irawadi and C. wangi by having a longer supratympanic spine, whereas C. maehongsonensis sp. nov. has a distinctly longer hindlimb than that of C. irawadi and C. wangi. As a result, two new species increase the list of known Calotes species in Thailand to four species; C. thailandensis sp. nov., C. maehongsonensis sp. nov., C. emma and C. goetzi.

Key words: Morphometric analysis, osteology, phylogenetic analysis, Southeast Asia, taxonomy

An uncollected male (A, B) on breeding season (March, 2025) and female (D) (CUMZ-R-2767) of Calotes thailandensis sp. nov. in rubber plantation (C) at Khlong Hoi Kong District, Songkhla Province, Thailand.

 Calotes thailandensis sp. nov. 
C. maehongsonensis sp. nov.


 Arpapan Prakobkarn, George R. Zug, Nontivich Tandavanitj and Thongchai Ngamprasertwong. 2026. Systematics of the Calotes irawadi complex (Squamata, Agamidae) with Two newly described Species from Thailand. ZooKeys. 1281: 69-104. DOI: doi.org/10.3897/zookeys.1281.175455 [03-06-2026]

Friday, April 17, 2026

[Paleontology • 2026] Eosphorosuchus lacrimosa • A Short-snouted ‘sphenosuchian’ with unusual Feeding Anatomy demonstrates that Ecological Specialization occurred early in Crocodylomorph Evolution

 

Eosphorosuchus lacrimosa
Margulis-Ohnuma, Ruebenstahl, Meyer & Bhullar, 2026
 
Art by Julio Lacerda

Abstract
The early evolution and diversification of Crocodylomorpha is a key component of vertebrate evolution on land but is somewhat poorly understood as a result of limited data. We describe Eosphorosuchus lacrimosa gen. et sp. nov., an early crocodylomorph from the Late Triassic of Ghost Ranch, New Mexico, whose cranial anatomy is divergent from that of other early crocodylomorphs (including Hesperosuchus agilis, to which it had been tentatively assigned), featuring an unusually short and osteologically reinforced facial region. A robust upper temporal arch and prominent surangular ridge indicate the presence of well-developed superficial external adductor musculature, which is divergent relative to pseudosuchians generally. These autapomorphies suggest specialization for a powerful bite. Bayesian and maximum parsimony phylogenetic analyses find E. lacrimosa outside of an H. agilis clade, near the base of Crocodylomorpha. The specializations of E. lacrimosa therefore represent the beginnings of ecological diversification within Crocodylomorpha among animals of a similar size, predating the Late Triassic appearance of Crocodyliformes and the Jurassic radiation of mesoeucrocodylians. Coexistence in the same single-event death assemblage of E. lacrimosa and H. agilis—two small early crocodylomorphs with functionally significant anatomical differences—suggests partitioning of terrestrial carnivorous niches within the ‘sphenosuchian’ grade.

Keywords: Crocodylomorpha, Sphenosuchia, Triassic, Hesperosuchus agilis, phylogenetics

Photographs and line drawings of the skull of Eosphorosuchus lacrimosa as preserved and prepared in right ventrolateral view (a, c) and left dorsolateral view (b, d). Grey shading represents matrix or bones of other individuals; halftone represents areas of breakage.
Abbreviations: an, angular; e, ectopterygoid; f, frontal; j, jugal; l, lacrimal; m, maxilla; n, nasal; pa, prearticular; pb, palpebral; pl, palatine; pm, premaxilla; po, postorbital; pt, pterygoid; sa, surangular; tpt, transverse process of the pterygoid. Scale bar is 2 cm.
 
ARCHOSAURIA Cope, 1869 (Gauthier & Padian [2020])
PSEUDOSUCHIA Zittel, 1887 

CROCODYLOMORPHA Hay, 1930 (emend. Walker [1970])

Eosphorosuchus lacrimosa gen. et sp. nov.
 
 Etymology: Eosphorosuchus derives from ‘Eosphoros,’ one of two Greek gods representing the planet Venus and the counterpart of Hesperos. As Eosphoros was the ‘dawn-bringer’, this name highlights both the dawning of crocodylomorph ecological diversity and the close historic association of this specimen with the genus Hesperosuchus. ‘Suchus’ derives from ‘soukhos’, Greek for crocodile. The specific epithet lacrimosa refers to the distinctive lacrimal region.


 
Miranda Margulis-Ohnuma; Alexander A. Ruebenstahl; Dalton L. Meyer and Bhart-Anjan S. Bhullar. 2026. A Short-snouted ‘sphenosuchian’ with unusual Feeding Anatomy demonstrates that Ecological Specialization occurred early in Crocodylomorph Evolution. Proc Biol Sci . 293 (2069): 20260130. DOI: doi.org/10.1098/rspb.2026.0130 [15 Apr 2026]

Monday, March 9, 2026

[Paleontology • 2026] Sonselasuchus cedrus • Osteology and Relationships of A New shuvosaurid (Pseudosuchia: Poposauroidea: Shuvosauridae) from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona, U.S.A


Sonselasuchus cedrus
Smith & Sidor, 2026

Artwork by Gabriel Ugueto

ABSTRACT
Shuvosauridae is a clade of pseudosuchian archosaurs currently represented by three named species characterized by a body plan strikingly convergent with that of ornithomimid theropod dinosaurs. This paper documents a new genus and species of shuvosaurid from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona. Sonselasuchus cedrus, gen. et sp. nov., is largely diagnosed by features of the maxilla, including a reduced body and anterior process, an enlarged subnarial foramen, and an expanded facet on the posterior process, although other unique cranial features are also noted herein. By contrast, its postcranial anatomy is largely similar to what has been described for other shuvosaurids, although subtle differences are noted. A phylogenetic analysis finds S. cedrus in an unresolved clade with Effigia okeeffeae and Shuvosaurus inexpectatus, likely as a result of non-overlapping missing data, particularly for the skull of Shuvosaurus. A review of the shuvosaurid fossil record indicates that shuvosaurids were persistent components of Late Triassic terrestrial vertebrate faunas in North America. S. cedrus is represented by a minimum number of 36 individuals, mostly skeletally immature, that occur within a multitaxic bonebed of almost exclusively disarticulated elements. An analysis of the relative size change of limb dimensions indicates the forelimb was growing on a negative allometric trajectory relative to the hindlimb, which is consistent with a transition in locomotory mode from quadrupedal to bipedal in S. cedrus during ontogeny.

Life restoration of Sonselasuchus cedrus as depicted by Gabriel Ugueto. Note the occurrence of individuals in both bipedal and quadrupedal stances.

SYSTEMATIC PALEONTOLOGY
ARCHOSAURIA Cope, 1869
PSEUDOSUCHIA Zittel, 1887–1890

PARACROCODYLOMORPHA Parrish, 1993
POPOSAUROIDEA Nopcsa, 1923

SHUVOSAURIDAE Chatterjee, 1993

SONSELASUCHUS CEDRUS gen. et sp. nov.

Etymology—For the genus, ‘Sonsela’ refers to the Sonsela Member of the Chinle Formation, the type section is located at the Sonsela Buttes on the Navajo Nation; ‘suchus’ is a Latinization of the Greek word soukhos, for the Egyptian crocodile deity Sobek, reflecting the pseudosuchian affinities of the taxon. The specific epithet, ‘cedrus’ is the genus name for the common cedar (actually the juniper, Juniperus spp.) and refers to Cedar Tank, the geographic feature in Petrified Forest National Park near the type locality.

Holotype—PEFO 47305/UWBM 119436, left maxilla.

Locality and Horizon—The Kaye Quarry (PFV 410/UWBM C2226) is located west of Cedar Tank at Petrified Forest National Park, Apache County, Arizona, U.S.A. (Fig. 1). The site is within the Jim Camp Wash beds of the Sonsela Member of the Chinle Formation and is Norian in age (Marsh et al., 2024). ...


Elliott Armour Smith and Christian A. Sidor. 2026. Osteology and Relationships of A New shuvosaurid (Pseudosuchia, Poposauroidea) from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona, U.S.A. Journal of Vertebrate Paleontology. e2604859. DOI: doi.org/10.1080/02724634.2025.2604859 [08 Mar 2026]

Monday, February 2, 2026

[Paleontology • 2026] Sauropia macrorhinus • The Smallest Tetrapod from the Middle Triassic of South America: A New procolophonoid parareptile from the Ladinian of Southern Brazil

 

Sauropia macrorhinus
Müller, Roberto-da-Silva, Aurélio & Kerber, 2026

Artwork by Caetano Soares.
 
Abstract
The Middle Triassic fossil record of South American parareptiles is scarce, with only a few procolophonoid specimens known. Here, we describe Sauropia macrorhinus gen. et sp. nov., a procolophonoid from the Ladinian (Pinheiros-Chiniquá Sequence of the Santa Maria Supersequence) of southern Brazil. The holotype, a nearly complete skull measuring only 9.5 mm in length, represents the smallest tetrapod known from these deposits. Its unique combination of features includes a proportionally large external naris, slender dorsal ramus of the maxilla, broad interorbital space, and three premaxillary teeth. Phylogenetic analyses consistently recover Sauropia macrorhinus gen. et sp. nov. as an early-diverging procolophonid, although its phylogenetic placement is complicated by its putatively immature ontogenetic stage. Its morphology provides valuable insight into early developmental stages of parareptiles and contributes to the understanding of Middle Triassic terrestrial ecosystems. Based on size and dentition, the new taxon was likely insectivorous or fed on other small invertebrates, possibly being predated upon by small carnivorous organisms. This discovery expands the taxonomic and ecological diversity known for Middle Triassic faunas of South America and enhances our understanding of the structure and complexity of terrestrial food webs in Middle Triassic ecosystems, preceding the Carnian Pluvial Episode and the rise of dinosaurs.

Results of the phylogenetic analysis and ordinary linear regressions. (a) Time-calibrated reduced global strict consensus tree depicting the phylogenetic position of Sauropia macrorhinus gen. et sp. nov. Values on the branches represent absolute (left) and GC (right) frequencies from symmetric resampling with no-zero weighting. The temporal bars for each OTU represent the maximum and minimum ages of each geological unit. Geological Time Scale was generated with GIMP version 2.8 (https://www.gimp.org/). Artistic representation of Sauropia macrorhinus gen. et sp. nov. by Caetano Soares. (b) Scatter plots of log-transformed measurements of the skull length and the orbitotemporal length of selected procolophonoids (n = 31). Linear regression line is shown in black, with the 0.95 confidence interval indicated by red dotted lines.




Systematic paleontology
Parareptilia Oslo, 1947
Procolophonoidea Romer, 1956
cf. Procolophonidae Seeley, 1888

Sauropia macrorhinus gen. et sp. nov.

Holotype CAPPA/UFSM 0510, an almost complete skull with mandible in occlusion.

Diagnosis: Sauropia macrorhinus differs from all other known procolophonoids with comparable material in (*local autapomorphies): Skull nearly as wide as it is long; proportionally large external naris (taller than the orbitotemporal fenestra)*; broad interorbital space in dorsal view; posterior margin of the orbitotemporal fenestra almost reaching the posterior end of the skull; premaxillae bearing three teeth; slender dorsal ramus of the maxilla*; absence of a temporal fenestra bordered anteriorly by the postorbital; U-shaped mandible in ventral view; and anterior maxillary teeth with a circular cross-section (not labiolingually expanded) and lacking a basal constriction.

Etymology: The genus name combines the Greek word “sauros” (= lizard) and the Portuguese word “piá” (= young boy), a regional term from southern Brazil rooted in Gaúcho culture, particularly in the state of Rio Grande do Sul, where it is commonly used to refer to a child. The name alludes to the small size and putative early ontogenetic stage of the holotype. The specific epithet combines the Greek words “makros” (= large) and “rhinos” (= nose or snout), in reference to the proportionally enlarged external naris of the holotype.

Artistic representation of Sauropia macrorhinus gen. et sp. nov. 
Artwork by Caetano Soares.

 
Rodrigo T. Müller, Lúcio Roberto-da-Silva, Pedro Lucas Porcela Aurélio and Leonardo Kerber. 2026. The Smallest Tetrapod from the Middle Triassic of South America: A New procolophonoid parareptile from the Ladinian of Southern Brazil. Scientific Reports. 16: 866. DOI: doi.org/10.1038/s41598-026-35114-3 [28 January 2026]

Friday, January 16, 2026

[Ichthyology • 2025] Aepysomanthias & Poroanthias gen. nov., Pelontrus, Zalanthias, ... • A 40-year Taxonomic Enigma: Multigene Phylogeny Resolves the Polyphyly of Plectranthias (Perciformes: Anthiadidae) and supports A Revised Taxonomy


Plectranthias, Pelontrus, Sayonara, Xenanthias, Zalanthias, 
 Aepysomanthias and Poroanthias Tang & Chen gen. nov. 

in Tang et Chen, 2025.  
 
Abstract
Anthiadidae, a family of shallow and deep-water reef-associated fishes, include about 250 species distributed widely from tropical to temperate regions, with the majority found in the tropical Indo-West Pacific (IWP). Despite their broad distribution, the phylogeny and taxonomy of this family remain unresolved, particularly at the generic level, due to challenges in sampling from deep-water zones. Plectranthias, the most species-rich genus, has been suspected of non-monophyly since its last revision over 40 years ago. In this study, we explore the phylogenetic relationships of anthiadids using a multigene dataset (one mitochondrial and four nuclear genes) from 103 specimens across 19 genera, with a focus on IWP Plectranthias. Our results confirm the polyphyly of Plectranthias, revealing seven distinct clades. Based on this new phylogenetic framework and morphological re-examinations, we propose a taxonomic revision, including the resurrection of the genera Pelontrus, Sayonara, Xenanthias, and Zalanthias, and the establishment of Aepysomanthias and Poroanthias Tang and Chen gen. nov. The revised taxonomy restricts Plectranthias to 20 currently recognized species.
 
systematics, taxonomic revision, anthias, Indo-West Pacific, Tropical Deep-Sea Benthos, osteology, diagnostic characters, Serranidae, new genus


 


Chi-Ngai Tang and Wei-Jen Chen. 2025. A 40-year Taxonomic Enigma: Multigene Phylogeny Resolves the Polyphyly of Plectranthias (Perciformes: Anthiadidae) and supports A Revised Taxonomy. Zoological Journal of the Linnean Society. 205(3); zlaf148. DOI: doi.org/10.1093/zoolinnean/zlaf148 [11 November 2025]