[Paleontology • 2025] Novel Record of Placodont Remains including A Henodus Cranium from the Upper Triassic Silves Group of the Algarve, southern Portugal

 

in Ruciński, Campos, Mateus et Werneburg, 2025. 

DOI: doi.org/10.1080/02724634.2025.2460445 

ABSTRACT

Recent fieldwork in the Upper Triassic deposits of the Silves Group in the Algarve, southern Portugal revealed novel cyamodontid placodont material. The collection includes a partial skull and numerous isolated armor plates from four localities in Silves and Loulé municipalities. The skull shows a strong affinity to henodontid placodonts, especially to Henodus chelyops from Tübingen-Lustnau in Germany. It shares features such as a rectangular outline of the cranium, occurrence of a broad spatulate rostrum, and toothless maxillae with curved longitudinally extending grooves. The only unambiguous difference observed pertains to the more robust and convex snout shape of the new specimen. Based on these multiple similarities, the specimen is identified as Henodus sp., but poor preservation prevents species-level identification. The new specimen from Portugal represents the second record of Henodus and illustrates a wider geographic distribution of that genus, extending beyond the Germanic Basin and reaching coastal areas near the westernmost branch of the Neotethys. The age of the deposits where the cranium was found is not well-established but refers to a time interval within the upper Carnian–Rhaetian, suggesting the specimen may be younger than other henodontid records. The novel Henodus material found in the continental, but likely the near-coastal depositional setting, concurs with the known records of brackish to the freshwater habitat of the other henodontid placodonts. The occurrence of abundant armor plates assigned to Cyamodontidae at multiple sites and stratigraphic horizons indicates that placodonts were common in the south Iberian margin.

Paleogeographic context of recorded Henodontidae remains.
A, paleogeographic map of the world during the Late Triassic (Colorado Plateau Geosystems Inc., license nr. #110719).
B, magnification of the map of the Late Triassic world illustrating the area of the western Neotethys. Approximate locations of Henodontidae-bearing sites are indicated by a star. Drawing of Henodus chelyops after Rieppel et al. (2000). Drawing of Parahenodus atacensis after de Miguel Chaves et al. (2018). Photos of the Portuguese specimen ML. A9182 is referred to as Henodus sp. with shape contour and established bone extensions (compare with Figs 4, 5). Scale bars represent 20 mm.

 Abbreviations: AB, Algarve Basin; AV, Avalonia; BM, Bohemian Massif; CEB, Central European Basin (which includes Germanic Basin); EEP, East European Platform; IB, Iberian Basin; IM, Iberian Massif; MG, Maghrabian-Gibraltar rift; SP, Sahara Platform.

 Summary of the placodont material from Upper Triassic of the Algarve.
A, reconstruction of Henodus by Jakub Kowalski and Piotr Janecki.
B, transversely expanded armor plate from Algarve, interpreted to possibly stem from the medial portion of Henodus carapace. C, equilateral armor plate from the Algarve interpreted to possibly stem from the marginal portion of Henodus carapace. D, photogrammetry-based image of Henodus cranium (ML. A9182).

Maciej Ruciński, Hugo Campos, Octávio Mateus and Ingmar Werneburg. 2025. Novel Record of Placodont Remains including A Henodus Cranium from the Upper Triassic Silves Group of the Algarve, southern Portugal. Journal of Vertebrate Paleontology. e2460445. DOI: doi.org/10.1080/02724634.2025.2460445 

[Paleontology • 2022] Morohasaurus kamitakiensis • A Fossil Monstersauria (Squamata: Anguimorpha) from the Lower Cretaceous Ohyamashimo Formation of the Sasayama Group in Tamba City, Hyogo Prefecture, Japan

Morohasaurus kamitakiensis 

Ikeda, Ota, Tanaka, Ikuno, Kubota, Tanaka & Saegusa, 2022

DOI: 10.1016/j.cretres.2021.105063 

  hitohaku.jp

Highlights: 

• We report a nearly complete left dentary of lizard from the Lower Cretaceous Sasayama Group, Japan.

• The material was described as a new monstersaur taxon “Morohasaurus kamitakiensis”.

• The new taxon might possibly be the oldest representative of the Monstersauria in the world.

• The present finding endorses the high taxonomic and ecological diversity of the Early Cretaceous lizard assemblage in Japan.

Abstract

A nearly complete left dentary of a lizard was excavated from the Lower Cretaceous Ohyamashimo Formation of the Sasayama Group in Tamba City, Hyogo Prefecture, Japan. The specimen shows several characters, which suggest its allocation in Monstersauria of the superfamily Varanoidea (Squamata: Anguimorpha). However, the specimen exhibits obvious differences from the known members of the whole Varanoidea. Thus, the specimen is described as a new taxon of cf. Monstersauria, Morohasaurus kamitakiensis gen. et sp. nov.. This new species is characterized by a suit of unique features, such as the sinuous posteroventral rim of the dentary with a large U-shaped upper notch and small V-shaped lower notch, posteroventral corner of intramandibular septum with a weakly pointed eminence projecting posteriorly, and unicuspid, curved trenchant teeth with distinct blade-like carinae on their mesial and distal sides without grooves or serrations. Morohasaurus kamitakiensis might possibly be the oldest representative of the Monstersauria.

Keywords: Monstersauria, Japan, Lower Cretaceous, Ohyamashimo Formation, Oldest representative

 

Tadahiro Ikeda, Hidetoshi Ota, Tomonori Tanaka, Kenji Ikuno, Katsuhiro Kubota, Kohei Tanaka and Haruo Saegusa. 2022. A Fossil Monstersauria (Squamata: Anguimorpha) from the Lower Cretaceous Ohyamashimo Formation of the Sasayama Group in Tamba City, Hyogo Prefecture, Japan. Cretaceous Research. 130, 105063. DOI: 10.1016/j.cretres.2021.105063   hitohaku.jp

篠山層群より発掘されたトカゲ類化石の記載論文の出版および臨時展示の実施について

  hitohaku.jp/research/h-research/20211125news.html

twitter.com/hitohaku/status/1463759813268041733

[Paleontology • 2019] Cyamodus orientalis • A New Species of Cyamodus (Placodontia, Sauropterygia) from the early Late Triassic of south-west China

Cyamodus orientalis

Wang, Li, Scheyer & Zhao, 2019

DOI: 10.1080/14772019.2018.1535455  

   twitter.com/JournalSystPal

Abstract

The Triassic eastern Tethyan faunas have continued to yield numerous specimens of marine reptile taxa in recent years. Nevertheless, compared with other sauropterygian clades, the diversity of placodonts in these faunas is low, and remains of this group are relatively rare in the fossil assemblages. Here, we report a new cyamodontoid specimen (ZMNH M8820) from the early Late Triassic of Guizhou, south-west China. This specimen is a nearly complete skeleton lacking only the forelimbs. It is distinct from other known Chinese placodonts as it features a large skull with remarkably enlarged supratemporal fenestrae and a small and less regularly arranged carapace. Interestingly, this new specimen resembles the European Cyamodus more than any Chinese cyamodontoid genera, particularly when considering the dentition and other cranial morphology. However, it differs from known Cyamodus species in some cranial features (e.g. epipterygoid fully ossified, posttemporal fenestra large, dentition derived) and the absence of a separate pelvic shield. Furthermore, based on an updated data matrix of placodonts, our phylogenetic results support the affinity of this new Chinese specimen with European Cyamodus species, and a new species, Cyamodus orientalis sp. nov., is erected here. This new material represents the first reported Cyamodus specimen in the world that preserves a three-dimensional skull with an associated postcranial skeleton and it extends the distribution of this genus into the early Carnian of the eastern Tethys. The existence of Cyamodus, a nearshore taxon, in south-west China at this time reveals greater similarity and more rapid intercommunication than previously known between western and eastern Tethyan vertebrate faunas, although the palaeobiogeographical origin and migration history of Cyamodontidae – and of other clades of placodont reptiles – are still obscure due to the scarcity of material from the northern and southern margins of the Palaeotethys.

Keywords: Placodontia, Guanling Biota, dentition, carapace, biogeography

Figure 2. Photographs and line drawings of the skull of Cyamodus orientalis sp. nov. (ZMNH M8820) in A, dorsal view; B, ventral view; C, left lateral view; D, occipital view.

Figure 1. Skeleton of Cyamodus orientalis sp. nov. (ZMNH M8820) with skull in original position.

Superorder Sauropterygia Owen, 1860 

Order Placodontia Cope, 1871 

Family Cyamodontidae Nopcsa, 1923 

Genus Cyamodus Meyer, 1863 

Type species. Cyamodus rostratus M€unster, 1839.

Cyamodus orientalis sp. nov.

Derivation of name. The species name is derived from the Latin word ‘oriens’ (East), referring to the Triassic marine reptile fauna in south China being located in the eastern Tethys, while all other known species of Cyamodus are from the western Tethys. 

Wei Wang, Chun Li, Torsten M. Scheyer and Lijun Zhao. 2019. A New Species of Cyamodus (Placodontia, Sauropterygia) from the early Late Triassic of south-west China. Journal of Systematic Palaeontology.  DOI: 10.1080/14772019.2018.1535455    

 twitter.com/JournalSystPal/status/1091299793563987973  

twitter.com/JournalSystPal/status/1089891157826568192

[Paleontology • 2018] Parahenodus atancensis • A New Placodont from the Upper Triassic of Spain provides New Insights on the Acquisition of the Specialized Skull of Henodontidae

Parahenodus atancensis

 de Miguel Chaves, Ortega & Pérez‐García, 2018

   DOI: 10.1002/spp2.1218 

Illustration: Eloy Manzanero  divulgauned.es

Abstract

Henodus chelyops Huene is considered to be a highly autapomorphic cyamodontoid placodont with specialized trophic adaptations relative to all the other members of Placodontia. It has been exclusively found in the Carnian (Upper Triassic) of Tübingen (Germany). Here we present a partial skull identified as a new cyamodontoid placodont from the Upper Triassic of El Atance (Guadalajara Province, Spain), Parahenodus atancensis gen. et sp. nov. It is recognized as the sister taxon of H. chelyops, both taxa composing the clade Henodontidae. An emended diagnosis for H. chelyops and Henodontidae is given here. Parahenodus atancensis shares with H. chelyops several cranial characters considered until now to be autapomorphic for the latter, but it also retains some states common in most cyamodontoids. Thus, the discovery of P. atancensis provides new information on the acquisition process of the highly specialized skull of the Henodontidae.

Key words: Placodontia, Cyamodontoidea, Henodontidae, Parahenodus atancensis, El Atance.

SYSTEMATIC PALAEONTOLOGY

SAUROPTERYGIA Owen, 1860

PLACODONTIFORMES Neenan et al., 2013

PLACODONTIA Cope, 1871

CYAMODONTOIDEA Nopcsa, 1923

CYAMODONTIDA Nopcsa, 1923

HENODONTIDAE Huene, 1936

Type species. Henodus chelyops Huene, 1936.

Included species. Henodus chelyops, Parahenodus atancensis gen. et sp. nov.

Emended diagnosis. Clade of Cyamodontida characterized by the following exclusive characters: flat skull; maxillae without tooth plates but with a deep ventral longitudinal groove; palatines with a single posterior tooth plate; upper temporal fenestrae reduced to absent; parietals broad and fan-shaped; presence of contact between the jugals and the squamosals; palatines separated from one another by long pterygoids; cephalic condyle of the quadrates posteriorly expanded and abutting a ventral flange of the squamosals.

Distribution. Upper Triassic (Carnian to Norian) of Europe (southern Germany and central Spain).

Genus HENODUS Huene, 1936 

Type species. Henodus chelyops Huene, 1936.

....

FIG. 1. Skull MUPA ATZ0104, holotype of the cyamodontoid placodont Parahenodus atancensis gen. et sp. nov., from the Upper Triassic of El Atance.
A, dorsal view. B, ventral view. C, schematic interpretation of the skull in dorsal view. D, schematic interpretation of the skull in ventral view.

Scale bars represent: 20 mm (A–D) 

Genus PARAHENODUS nov. 

Type species. Parahenodus atancensis sp. nov. 

Parahenodus atancensis sp. nov. 

Derivation of name. Para (paqa), Greek for ‘near’ or ‘beside’, implying morphological closeness to Henodus Huene, 1936; atance, from El Atance, the fossil site; and ensis, a Latin adjectival suffix meaning ‘pertaining to’.

FIG. 2. Strict consensus tree obtained from our phylogenetic analysis based on the cranial data matrix of Neenan et al. (2015) showing the position of the cyamodontoid placodont Parahenodus atancensis gen. et sp. nov., from the Upper Triassic of El Atance. Bootstrap frequencies that exceed 50% (top) and Bremer support values (bottom) are indicated.

  

Carlos de Miguel Chaves,  Francisco Ortega and Adán Pérez‐García. 2018. A New Placodont from the Upper Triassic of Spain provides New Insights on the Acquisition of the Specialized Skull of Henodontidae.  Papers in Palaeontology.  DOI: 10.1002/spp2.1218

Describen una nueva especie de placodonto que habitó en Guadalajara durante el Triásico Superior  divulgauned.es/placodonto/ via @divulgauned

 twitter.com/frco_ortega/status/999921997692846082

 twitter.com/Tortugologo/status/996073241394413573