[Paleontology • 2026] Silescelida acristata • A New eucrocopodan Archosauriform from the Middle Triassic of southern Brazil and the Phylogeny of Euparkeriidae

Silescelida acristata 

Garcia, Cerqueira, Battista,  Andrade & Müller, 2026

DOI: doi.org/10.1038/s41598-026-53740-9 

life reconstruction by Matheus Fernandes Gadelha. 

Abstract

Archosauriformes comprise a diverse range of reptiles, including the crown-group Archosauria, which flourished during the Triassic Period. Early-diverging archosauriforms, such as proterosuchids and erythrosuchids, are becoming progressively well-known due to recent studies and consistently resolve at the base of the clade. More crownward, Eucrocopoda includes archosauriform taxa that increasingly approximate the ancestral archosaur body plan. Early-diverging eucrocopodan archosauriforms have a widespread paleogeographic record but remain poorly understood in terms of ingroup relationships. Within this radiation, Euparkeriidae is particularly challenging, because its ingroup composition and monophyly is debated, with some authors supporting a non-monospecific Euparkeriidae, whereas others fail to recover this hypothesis. The eponymous Euparkeria capensis is known from the Early to Middle Triassic of South Africa, whereas other putative euparkeriids are primarily known from the Early to Middle Triassic of China, Germany, Poland, and Russia. Here, we describe a new early-diverging eucrocopodan (Silescelida acristata gen. et sp. nov.) from the Middle Triassic of southern Brazil. Phylogenetic analyses incorporating this taxon suggest a possible placement within Euparkeriidae, though its position shows instability depending on the operational taxonomic units considered, especially among other putative euparkeriids. This discovery not only informs on the temporal and paleogeographic distribution of euparkeriids but also sheds light on the origin and early evolution of eucrocopodans, representing the first record of this archosauriform grade in the Triassic of Brazil. More broadly, the new taxon underscores the significance of South American Triassic deposits within the evolutionary history of archosauriforms.

Archosauromorpha von Huene, 1946 sensu Gauthier, 2020

Archosauriformes Gauthier et al., 1988 sensu Gauthier, 2020 

Eucrocopoda Ezcurra, 2016

cf. Euparkeriidae von Huene, 1920 sensu Sookias and Butler, 2013

Provenance and material of Silescelida acristata gen. et sp. nov.
 (A) Map of the Posto site and the surface distribution of the geologic units in the area. (B) General view of the Posto site. (C) Studied specimen MCP 4186-PV (holotype of Silescelida acristata gen. et sp. nov.) showing association between its elements prior to mechanical preparation.
(D) Silhouette and preserved skeletal elements (not to scale) of Silescelida acristata gen. et sp. nov. (ilium reversed).

Abbreviations: fe, femur; il, ilium; sc, scapula. Silhouette and life reconstruction of Silescelida acristata gen. et sp. nov. by Matheus Fernandes Gadelha. Map was generated with GIMP 3.0 (gimp.org) based on the geological map of Rio Grande do Sul (https://rigeo.sgb.gov.br/bitstream/doc/10301/2/Geologico_MDT.pdf).

Silescelida acristata gen. et sp. nov.  

Holotype. MCP 4186-PV, a left scapula, a right ilium, and a left femur (Fig. 1C, D). The elements were found in association (attached to each other) and are size-compatible; therefore, they are considered to belong to the same individual.

Type locality, age, and horizon. Posto (or Posto de Gasolina; Fogliarini) site (29°37’38.9”S 53°22’06.5”W), municipality of Dona Francisca, Rio Grande do Sul, Brazil (Fig. 1A, B). Dinodontosaurus AZ of the Pinheiros-Chiniquá Sequence of the Santa Maria Supersequence, Paraná Basin51,52. It is considered Ladinian in age30,35,53,54,55,56,57,58.

Diagnosis. The holotype of Silescelida acristata differs from all other known non-archosaurian archosauriforms in the following combination of traits: scapular blade without an anteroposterior constriction at its base; asymmetrical expansion of the scapular blade at its dorsal portion; straight posterior margin of the scapular blade, forming a right angle with the dorsal margin of the glenoid; elliptical tuber for the m. triceps dorsal to the glenoid; dorsal margin of the dorsal iliac blade straight in dorsal and lateral views; dorsal iliac blade as deep as the acetabulum; notch between the ischiadic peduncle and the ventral apex of the medial acetabular wall; medially expanded femoral head; absence of a longitudinal groove on the proximal surface of the femoral head; posteromedial tuber as the only well-developed tuber on the femoral head; absence of an elevated mound or crest-like structure as the attachment site for the m. caudofemoralis (local autapomorphy); extensor fossa on the anterior surface of the femoral distal end; distal femoral condyles with the same degree of ventral development (not uneven).

Etymology. The generic name combines the Latin siles (“silence”) and the Greek skelēs (“hind leg”), referencing the loss of the proximal femur bearing the specimen’s collection code, which obscured its provenance until its recent rediscovery. The specific epithet derives from the Latin prefix a- (“without”) and cristāta (“crested”), referring to the absence of a crest or flange attachment site for the m. caudofemoralis (= fourth trochanter), a diagnostic feature of the taxon.

Silescelida acristata gen. et sp. nov. life reconstruction.

 Artwork by Matheus Fernandes Gadelha. 

Biogeography of early-diverging eucrocopodans and paleoart depicting Silescelida acristata gen. et sp. nov. in life.
 (A) Triassic world map depicting the paleogeographic distribution of early-diverging eucrocopods. Classification is based on the phylogenetic analyses in this contribution. Silhouettes (not to scale) based on the skeletal reconstruction of Euparkeria capensis by Demuth et al.83. Dorosuchus neoetus is based on the type-series and Osmolskina czatkowicensis is based on the holotype.
(B) Silescelida acristata gen. et sp. nov. life reconstruction. Artwork by Matheus Fernandes Gadelha. Map was generated with GIMP 3.0 (gimp.org) based on The Paleobiology Database (paleobiodb.org).

 

Maurício S. Garcia, Gabriela M. Cerqueira, Francesco Battista, Marco B. de Andrade and Rodrigo T. Müller. 2026. A New eucrocopodan Archosauriform from the Middle Triassic of southern Brazil and the Phylogeny of Euparkeriidae. Scientific Reports. 16: 16585. DOI: doi.org/10.1038/s41598-026-53740-9  [10 June 2026]

 

[Paleontology • 2026] Nagatitan chaiyaphumensis • The First Sauropod Dinosaur (Titanosauriformes: Euhelopodidae) from the Lower Cretaceous Khok Kruat Formation of Thailand enriches the Diversity of somphospondylan titanosauriforms in Southeast Asia

Nagatitan chaiyaphumensis 

Sethapanichsakul, Khansubha, Manitkoon, Hanta, Mannion & Upchurch, 2026

นาคาไททัน ชัยภูมิเอนซิส  ||  DOI: doi.org/10.1038/s41598-026-47482-x 

Artwork by facebook.com/DinoThaiThai

 facebook.com: Perth Thitiwoot

Abstract

Sauropod dinosaur remains comprise the majority of the Mesozoic vertebrate fossil record in Thailand. However, they are rare and fragmentary in the Aptian–Albian (Lower Cretaceous) Khok Kruat Formation, the stratigraphically youngest fossil-bearing Mesozoic Thai stratigraphic unit. Based on a partial postcranial skeleton, we present the first diagnostic sauropod specimen from this formation, which represents a new somphospondylan titanosauriform, Nagatitan chaiyaphumensis n. gen. n. sp. Nagatitan is diagnosed by two autapomorphies and a unique character combination, including the presence of two distinct hyposphene-hypantrum morphologies within the middle–posterior dorsal vertebrae. Phylogenetic analyses under maximum parsimony, using a data matrix containing 153 taxa and 570 characters, produce well-resolved topologies that place Nagatitan within the somphospondylan clade Euhelopodidae. Nagatitan does not form an endemic subclade with the approximately contemporaneous Southeast Asian euhelopodids Phuwiangosaurus and Tangvayosaurus, with a suite of anatomical features distinguishing these taxa. We estimate a body mass of 25–28 tonnes for Nagatitan, and suggest it was part of a broader middle Cretaceous body size increase in Asian titanosauriforms, facilitated by rising temperatures and expanded suitable habitat. The discovery of Nagatitan expands the known diversity of Southeast Asian sauropods and improves our understanding of titanosauriform biogeography within the region.

Schematic representation of the skeleton of Nagatitan chaiyaphumensis gen. et. sp. nov. Preserved bones are highlighted. Scale bar equals 1 m.

Systematic palaeontology

Dinosauria Owen, 1842

Saurischia Seeley, 1887

Sauropoda Marsh, 1878

Titanosauriformes Salgado, Coria & Calvo, 1997

Somphospondyli Wilson & Sereno, 1998

Euhelopodidae Romer, 1956 (sensu D’Emic, 2012)

Nagatitan chaiyaphumensis gen. et sp. nov.

นาคาไททัน ชัยภูมิเอนซิส

Holotype: SM2025-1-546 to SM2025-1-556—four dorsal vertebrae, five dorsal ribs, four sacral vertebrae, five sacral ribs, right humerus, right ilium, left and right pubis, mostly complete right femur.

Diagnosis: Nagatitan can be diagnosed by a unique combination of characters (autapomorphies denoted with an asterisk): (1) paired postzygapophyseal centrodiapophyseal fossa present on posterior dorsal neural arches; (2*) hyposphene of middle dorsal vertebrae exhibits a triangular morphology, becoming a vertical ridge in posterior dorsal vertebrae; (3) parapophysis positioned dorsal to the prezygapophysis on posterior dorsal neural arches; (4) spinopostzygapophyseal laminae of middle and posterior dorsal neural spines divided into lateral and medial branches throughout their length; (5) bifurcated middle dorsal neural spines; (6*) triangular anterior aliform processes present on posterior dorsal neural spines; (7) prominent bulge on posterolateral margin of humerus, approximately level with the deltopectoral crest, that interrupts the lateral humeral margin in anterior view; (8) rounded proximolateral corner of humerus; (9) humeral shaft exhibits a high eccentricity value (> 2.5); (10) distal end of the pubis transversely expanded along the lateral surface relative to the shaft; and (11) proximal third of femur with anteroposteriorly narrowed lateral margin forming a flange-like trochanteric shelf and a medially bounding vertical ridge along the posterior surface.

Locality and Horizon: Ban Pha Nang Sua, Nong Bua Rawe District, Chaiyaphum Province, Thailand; Khok Kruat Formation, Aptian–Albian, upper Lower Cretaceous. 

Etymology: The generic name is derived from Naga, referring to the mythological serpent-like creature found in various Asian cultures, especially in northeastern Thailand, often associated with water and Buddhism, and titan, a giant in Greek mythology. The specific epithet is derived from the province of Chaiyaphum, Thailand.

3D skeletal reconstruction by Matus Charoenjit

Stylized life reconstruction of Nagatitan chaiyaphumensis gen. et. sp. nov. within the arid floodplains of late Early Cretaceous Aptian–Albian Thailand  

Artistic reconstruction by Patchanop Boonsai (Draconos Takeji) 

Non-sauropod faunal remains discovered in the Ban Pha Nang Sua locality:
(a) Allosauroid tooth (SDM2025-1-562) in labial view, (b) spinosaurid tooth (SDM2025-1-561) in labial view, (c) crocodyliform tooth (specimen lost during the excavation) in lingual view, (d) Heteroptychodus steinmanni tooth (SDM2025-1-563) in apical view, and (e) mold of cf. Yunnanoconcha sp. (SDM2025-1-560) in external view. (f) Stylized illustration displaying the vertebrate fauna assemblage known from the Khok Kruat Formation modified from Manitkoon et al. 2023. Shaded black silhouette indicate tentative taxa. Nagatitan chaiyaphumensis gen. et sp. nov. shaded in blue. Scale bars equal 10 mm.

  

 

Thitiwoot Sethapanichsakul, Sasa-On Khansubha, Sita Manitkoon, Rattanaphorn Hanta, Philip D. Mannion and Paul Upchurch. 2026. The First Sauropod Dinosaur from the Lower Cretaceous Khok Kruat Formation of Thailand enriches the Diversity of somphospondylan titanosauriforms in Southeast Asia. Scientific Reports. 16; 12467. DOI: doi.org/10.1038/s41598-026-47482-x [14 May 2026]

 facebook.com/perth.thitiwoot/posts/3901053680026079

[Paleontology • 2026] Jinjuichnus procerus • New large Pterosaur Tracks from Korea and their implications on terrestrial behavior

Jinjuichnus procerus and tetrapod trackmakers. The neoazhdarchian trackmaker is following the small vertebrate.

Jung, Kim, Xing & Choi, 2026

DOI: doi.org/10.1038/s41598-026-48019-y 

illustration created by Jun Seung Yi.  

Abstract

Pterosaurs were important components of Mesozoic ecosystems, occupying diverse ecological niches from the Late Triassic to the end of the Cretaceous. Among them, neoazhdarchians have been hypothesized as terrestrial carnivorous based on anatomical and functional evidence, yet direct indications of predation on land have remained elusive. Here we report Jinjuichnus procerus ichnogen. et ichnosp. nov., a new pterosaur track discovered in the Jinju Formation of South Korea. The track, characterized by a compact and long metatarsus in its pedal configuration, is consistent with neoazhdarchian pterosaurs. The trackway is preserved in close association with a small tetrapod trackway that exhibits abrupt changes in direction and increased stride length. This association provides the potential ichnological evidence of terrestrial vertebrate interaction by a pterosaur. Nonetheless, an alternative interpretation of the two trackways remains possible, making it difficult to confirm any direct interaction between the trackmakers. The paired trackways offer insight into the factors to consider when evaluating potential interactions with the trackmaker. While scenarios such as predation remain ambiguous, they nonetheless highlight the interpretive complexity inherent in assessing behavioral associations preserved in trackway assemblages.

Life reconstruction drawing of Jinjuichnus procerus and tetrapod trackmakers. The neoazhdarchian trackmaker is following the small vertebrate. The illustration in this figure was created by Jun Seung Yi. Reproduced with permission from the copyright holder and published under CC BY 4.0 license.

Systematic ichnology

Pterosauria Kaup 1834.

Pterodactyloidea Plieninger, 1901.

Ichnofamily Agadirichnidae Masrour et al., 2018.

Ichnogenus Junjuichnus ichnogen. nov.

Etymology – The generic name Jinjuichnus combines Jinju, the location where the specimen was found, with Greek ichnus (ἴχνος), meaning “track.”

Ichnospecies Jinjuichnus procerus ichnogen. et ichnosp. nov.

Etymology. The specific name procerus is a Latin adjective meaning “extended” or “elongated,” describing the notably elongated manus impressions.

  

Conclusion: 

A new pterosaur ichnotaxon, Jinjuichnus procerus et ichnogen. et ichnosp. nov., is described from the Lower Cretaceous Jinju Formation of South Korea. This trackway is characterized by a large size, highly elongated digit III, a blunt digit I, and a wide manus divarication angle, features that distinguish it from previously reported pterosaur ichnotaxa. Based on pedal morphology and comparative analysis, the trackmaker is most plausibly attributed to a neoazhdarchian pterosaur that inhabited the Korean Peninsula during the Early Cretaceous.

...

Jongyun Jung, Kyung Soo Kim, Lida Xing and Byung-Do Choi. 2026. New large Pterosaur Tracks from Korea and their implications on terrestrial behavior. Scientific Reports. 16: 12363. DOI: doi.org/10.1038/s41598-026-48019-y [16 April 2026]

 

[Herpetology • 2026] Hemiphyllodactylus dayaoensis, H. maguanensis, H. xingyiensis, ... • Systematic Revision of the Hemiphyllodactylus yunnanensis complex (Squamata: Gekkonidae) with Descriptions of Six New Species

 

 Hemiphyllodactylus yunnanensis  (Boulenger, 1903)

Hemiphyllodactylus dayaoensis sp. nov.;

H. jingdongensis sp. nov.;

H. maguanensis sp. nov.;

H. shuangbaiensis sp. nov.

Zhou, Wang, Han, Ang, Zhang, Liu & Rao, 2026

DOI: doi.org/10.1038/s41598-026-35912-9

Abstract

Hemiphyllodactylus Bleeker 1860, one of the fastest-growing genera in the Gekkonidae, comprises 22 species distributed in China, among which Hemiphyllodactylus yunnanensis is believed to be a species complex. Despite the gradual description of Hemiphyllodactylus populations in various regions of China as new species in the past decade, the taxonomy of the Hemiphyllodactylus yunnanensis complex remains unresolved. We collected Hemiphyllodactylus populations of the yunnanensis complex from 11 locations. Based on 1809 bp dataset (1039 bp mitochondrial ND2 gene, fragments of 375 bp nuclear C-mos + 395 bp PDC genes) and a solo 1039 bp NADH dehydrogenase subunit 2 (ND2) sequence fragment dataset, the constructed phylogenetic topology revealed that our samples fell into seven independent lineages of Clade 7. Automatic Barcode Gap Discovery (ABGD) results are consistent with our phylogenetic findings. The uncorrected genetic pairwise distance between populations exceeded 4.2% in ND2 gene, and there were also significant morphological differences among them. Therefore, we consider the specimens that cluster with the topotype specimens as true Hemiphyllodactylus yunnanensis, and describe the other six lineages as new species, respectively.

Keywords: Integrative taxonomy, Yunnan province, Cryptic species, Slender geckos 

Hemiphyllodactylus yunnanensis
  (A) KIZ2023Z097, Topotype, female in life; (B) KIZ2023Z098, Topotype, male in life;
(C) KIZ2023Z311, male in life; (D) KIZ2023Z082, female in life.

 

Hemiphyllodactylus dayaoensis sp. nov. (A) KIZ2023Z177, Holotype, male in life; (B) KIZ2023Z176, Paratype, female in life.
Hemiphyllodactylus jingdongensis sp. nov. (A) KIZ2023Z212, Paratype, male in life; (B) KIZ2023Z211, Holotype, female in life.
Hemiphyllodactylus maguanensis sp. nov. (A) KIZ2023Z332, Paratype, male in life; (B) KIZ2023Z331, Paratype, female in life; (C) KIZ2023Z336, Paratype, female in life; (D) KIZ2023Z333, Paratype, female in life.

Hemiphyllodactylus dayaoensis sp. nov.  

 

Etymology: The scientific name “dayaoensis” is derived from its type locality Dayao County in Yunnan province. we suggest Dayao Slender Gecko in English and “大姚半叶趾虎(Dà Yáo Bàn Yè Zhǐ Hǔ)” in Chinese.

Hemiphyllodactylus jingdongensis sp. nov.  

Etymology: The scientific name “jingdongensis” is derived from its type locality Jingdong County in Yunnan province. we suggest Jingdong Slender Gecko in English and “景东半叶趾虎(Jǐng Dǒng Bàn Yè Zhǐ Hǔ)” in Chinese.

Hemiphyllodactylus maguanensis sp. nov.  

Etymology: The scientific name “maguanensis” is derived from its type locality Maguan County in Yunnan province. we suggest Maguan Slender Gecko in English and “马关半叶趾虎(Mǎ Guān Bàn Yè Zhǐ Hǔ)” in Chinese.

Hemiphyllodactylus shuangbaiensis sp. nov. (A) KIZ2023Z120, Paratype, female in life; (B) KIZ2023Z125, Holotype, female in life.
Hemiphyllodactylus xingyiensis sp. nov. (A) KIZ2023Z303, Paratype, female in life; (B) KIZ2023Z308, Holotype, female in life.
Hemiphyllodactylus yuanyangensis sp. nov. (A) KIZ2023Z392, Paratype, male in life; (B) KIZ2023Z387, Holotype, male in life.

Hemiphyllodactylus shuangbaiensis sp. nov.  

Etymology: The scientific name “shuangbaiensis” is derived from its type locality Shuangbai County in Yunnan province. we suggest Shuangbai Slender Gecko in English and “双柏半叶趾虎(Shuāng Bǎi Bàn Yè Zhǐ Hǔ)” in Chinese.

Hemiphyllodactylus xingyiensis sp. nov. 

Etymology: The scientific name “xingyiensis” is derived from its type locality Xingyi County in Yunnan province. we suggest Xingyi Slender Gecko in English and “兴义半叶趾虎(Xīng Yì Bàn Yè Zhǐ Hǔ)” in Chinese.

Hemiphyllodactylus yuanyangensis sp. nov. 

Etymology: The scientific name “yuanyangensis” is derived from its type locality Yuanyang County in Yunnan province. we suggest Yuanyang Slender Gecko in English and “元阳半叶趾虎(Yuán Yáng Bàn Yè Zhǐ Hǔ)” in Chinese.

Hongxin Zhou, Jishan Wang, Keguo Han, Yufan Ang, Dongru Zhang, Shuo Liu and Dingqi Rao. 2026. Systematic Revision of the Hemiphyllodactylus yunnanensis complex with Descriptions of Six New Species. Scientific Reports. 16: 5562. DOI: doi.org/10.1038/s41598-026-35912-9 [10 February 2026]

[Ichthyology • 2026] Gitchak nakana • A miniature, subterranean, blind cobitid loach (Cypriniformes: Cobitidae) is the first groundwater-dwelling fish from Northeast India

Gitchak nakana

Britz, Marak, Velentina, Lokeshwor, Raghavan, Pinion & Rüber, 2026

DOI: doi.org/10.1038/s41598-026-40425-6  

  x.com/Meenkaran1

Abstract

Subterranean animals are commonly met with considerable fascination, by both laymen and biologists. While most of these animals have been reported from caves, some species have adapted to other underground habitats. One special subterranean aquatic habitat are aquifers, which are home to a number of invertebrates and fishes. Of the more than 300 known subterranean fishes, fewer than 10% have been recovered from aquifers and are encountered only rarely and serendipitously. Here we report the discovery of a tiny, blind loach of the family Cobitidae from a dug-out well in Assam, India, which exhibits a number of characters commonly associated with subterranean life, so-called troglomorphies. This loach, described here as Gitchak nakana, represents a new genus and species, differing from all other genera of cobitids by a number of unique characters. The most unusual among these is the complete lack of a skull roof with the brain covered dorsally only by skin. Gitchak nakana is the first aquifer-dwelling (phreatobitic) fish from Northeast India, and marks the first discovery of a previously unknown subterranean fauna in this part of Asia.

Gitchak nakana. (a) ZSI FF11123, holotype, 20.8 mm SL, in life, sides reversed, showing overall appearance, note presence of large eggs in body cavity and numerous fat globules (reflective spheres) along dorsal midline and postanal ventral midline. (b) same specimen, after preservation. (c) same specimen, µCT-image to illustrate presence of eight large eggs arranged in a longitudinal series. (d) same specimen, in life, actively swimming in the water column; note large yellow eggs and blood red liver. (e) KUFOS2025.F.11.51, non-type, 16.4 mm SL, in life, close-up of lateral head and body; note swimbladder visible through body wall. (f) KUFOS:2025.FT.11.6, paratype, 20.0 mm SL, frontal view of head to illustrate crown of barbels; note large-calibre red blood vessels supplying rostral (rb), maxillary (mxb) and mandibular (mdb) barbels and small-calibre vessels supplying nasal (nb) and tiny mental barbels (marked by arrow).

Taxonomy 

Gitchak, new genus 

Diagnosis. Gitchak is a member of the family Cobitidae as evidenced by (i) the modification of lateral ethmoid into a bifurcated subocular spine, which articulates with the orbitosphenoid, (ii) the reduction of the endopterygoid into a rod-like element, (iii) the absence of contact between orbitosphenoid and pterosphenoid and (iv) the outer arm of the os suspensorium completely surrounding anterior swimbladder chamber.

Etymology. The genus name is derived from the Garo word gitchak, meaning red, alluding to the striking red life colour of this loach. Treated here as a noun in the feminine gender.

Gitchak nakana, new species.

 

Etymology. The specific name is derived from the Garo words na·tok, fish, and kana, blind, referring to the absence of eyes in this species, a noun in apposition.

 

Ralf Britz, Wimarithy K. Marak, Kangjam Velentina, Yumnam Lokeshwor, Rajeev Raghavan, Amanda K. Pinion and Lukas Rüber. 2026. A miniature, subterranean, blind cobitid loach, Gitchak nakana, new genus and species, is the first groundwater-dwelling fish from Northeast India. Scientific Reports. 16: 7746. DOI: doi.org/10.1038/s41598-026-40425-6 [26 February 2026]

  x.com/Meenkaran1/status/2027384099984519338

[PaleoMammalogy • 2026] Notopolytheles joelis • First unambiguous evidence of Multituberculata from the Late Cretaceous of South America

 

upper left: upper molar Notopolytheles joelis in occlusal view.

lower left: plagiaulacoid tooth of Argentodites coloniensis.

Notopolytheles joelis

Gelfo, Goin & Vega, 2025

  DOI: doi.org/10.1038/s41598-025-25255-2

Abstract

We report a left upper first molar of a multituberculate mammal, from the Upper Cretaceous La Colonia Formation, Chubut Province, Argentina, which is here assigned to Notopolytheles joelis gen. et sp. nov. (Cimolodonta,?Neoplagiaulacidae). Multituberculates have been previously reported from Gondwanan land masses, but to date, only records from Australia, Madagascar, and India have been taxonomically undisputed. In South America, all previous assignments were debated or later referred to Gondwanatheria. These records include isolated molars attributed to Ferugliotheriidae and Argentodites coloniensis, only known from a plagiaulacoid premolar and originally assigned to the ?Cimolodonta. Since no molar with definitive multituberculate features could ever be found in the Upper Cretaceous of Patagonia, A. coloniensis was considered a junior synonym of the ferugliotheriid Ferugliotherium windhauseni. Notopolytheles joelis gen. et sp. nov. displays a typical multituberculate molar configuration of three rows of tetrahedral cups, with a cusp formula of 7B:8M:4L similar to Neoplagiaulacidae. The lower position of the buccal cusp row supported by a single large labial root suggest a high level of endemism. This finding provides strong and renewed support for the hypothesis that ferugliotheriids lack a plagiaulacoid p4 and that Argentodites coloniensis is indeed a multituberculate.

Keywords: South America, Patagonia, La Colonia Formation, Late Cretaceous, Multituberculata, Gondwanatheria

Left: upper molar of the new species Notopolytheles joelis in occlusal view.
Right: plagiaulacoid tooth of Argentodites coloniensis.

Scale bar = 1 mm.

Reconstruction of the small multituberculate Notopolytheles joelis from the Late Cretaceous La Colonia Formation, Chubut Province, Argentina. (by Manuel Copello)

Mammalia Linnaeus, 1758.

Multituberculata Cope, 1884.

Cimolodonta McKenna, 1975.

?Neoplagiaulacidae Ameghino, 1890.

Notopolytheles joelis gen. and sp. nov.

Etymology: The genus name refers to ‘southern multituberculate’ and derives from three Greek roots: noto- (south), poly- (many), and theles (protuberance), the last two in reference to the multiple cusps characteristic of multituberculate teeth. The specific epithet joelis is named after Joel Hernán Carino, who discovered the tooth.

Javier N. Gelfo, Francisco J. Goin  and Nahuel A. Vega. 2025. First unambiguous evidence of Multituberculata from the Late Cretaceous of South America. Scientific Reports. 15, 41500. DOI: doi.org/10.1038/s41598-025-25255-2 [24 November 2025]

 

A TINY FOSSIL TOOTH REWRITES THE HISTORY OF SOUTHERN MAMMALS

https://go.nature.com/4rnCGwU

 

[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

DOI: doi.org/10.1038/s41598-026-35114-3 

 Researchgate.net/publication/400168701

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]

 Researchgate.net/publication/400168701_a_new_procolophonoid_parareptile_from_the_Ladinian_of_Southern_Brazil

[PaleoEntomology • 2025] Shaykayatcoris michalskii • A New fossil plesiomorphic Flat Bug (Aradidae) suggests widespread flower visiting in Heteroptera during the Mesozoic

  

 Shaykayatcoris michalskii

Kóbor & Szabó, 2025

  

DOI: doi.org/10.1038/s41598-025-15559-8 

artistic reconstruction by Márton Zsoldos

Abstract 

The phenomenon of flower visiting (anthophily) and the pollination, though becoming prevalent with the rise of flowering angiosperms, hypothesized to have originated from the antagonistic relationship of florivory between insects and gymnosperms in the Upper Jurassic. Though not commonly known, this behaviour has been documented in several instances among the representatives of the suborder Heteroptera, i.e., the true bugs. Here, we describe Shaykayatcoris michalskii gen. nov., sp. nov., the first known representative of the plesiomorphic flat bug (Aradidae) subfamily Prosympiestinae in the Upper Cretaceous Burma Terrane amber fauna (Lowermost Cenomanian, ca. 99 Mya). Besides expanding the knowledge on the heteropteran insect fauna of the Lagerstätte, the discovery of this new true bug provides intriguing insights into the evolutionary history of true bugs. First, the new record corroborates that the subfamily Prosympiestinae is a Gondwanan relict group among the representatives of flat bugs. Second, this insect presents the first known incidence of iridescent colouration in flat bugs with a tentative role of camouflage, suggesting a more exposed lifestyle compared to the apomorphic lineages of flat bugs, which have adapted to live under tree bark. Third, the iridescence and the high amount of pollen among the syninclusions suggest that the insect was likely to be anthophilous. The suspected presence of anthophily in such a specialised heteropteran insect group like Aradidae suggests that anthophily was more widespread among the Mesosoic true bugs than it can be observed in the case of extant taxa.

Keywords: Heteroptera, Aradidae, Fossil, Iridescence, Anthophily

Reconstructions of Shaykayatcoris michalskii gen. et sp. nov.: 
(a) line drawing of the second author (parts of femora visible in dorsal view were omitted), (b) artistic reconstruction by Márton Zsoldos, Hungarian palaeoartist.

Systematic palaeontology

Order Hemiptera Linnaeus, 1758.

Suborder Heteroptera Latreille, 1810.

Infraorder Pentatomomorpha Leston, Pendergrast and Southwood, 1954.

Superfamily Aradoidea Brullé, 1836.

Family Aradidae Brullé, 1836.

Subfamily Prosympiestinae Usinger and Matsuda, 1959.

Shaykayatcoris Kóbor and Szabó gen. nov.

Differential diagnosis: Shaykayatcoris gen. nov. possesses the following synapomorphies shared with representatives of the tribe Prosympiestini: gular area smooth (in Llaimacorini gular area with a shallow longitudinal groove), peritreme situated anteriorly to hind coxa (in Llaimacorini peritreme situated close to the middle coxa). The bristle of the peritreme characteristic of tribe Prosympiestini is not observable, but it may have been broken off when trapped in resin. Shaykayatcoris gen. nov. is macropterous, possessing a triangular scutellum (shared synapomorphy with Prosympiestus Bergroth, 1894; other prosympiestine genera are brachypterous), length of head greater than the width (shared synapomorphy with Prosympiestus, length of head distinctly shorter than width in the other prosympiestine genera), antenniferous tubercle reduced (autapomorphy, antenniferous tubercles well-developed or even produced laterally in other prosympiestine genera), postocular region slightly concave (autapomorphy, postocular region convex or straight in other prosympiestine genera), width of pronotum is 1.3× greater than length (width of pronotum is at least twice greater than length in other prosympiestine genera), scutellum is slightly shorter than pronotum (autapomorphy, scutellum is at least somewhat shorter in other prosympiestine genera), hemelytron with fine, sparse punctuation at claval furrow and along veins of corium (autapomorphy, hemelytron extensively and strongly punctate in Prosympiestus).

Etymology: Generic name masculine. The name of the genus is derived from the Burmese word ရှေးခေတ် (shayyhkayat), meaning ’ancient’ and the Greek κοριός (koriós = coris), meaning ’bug’.

Shaykayatcoris michalskii Kóbor and Szabó sp. nov.

Type locality and horizon: Upper Cretaceous, lower Cenomanian (98.79 ± 0.62 Ma, according to Shi et al.24; from an amber mine in Hukawng Valley, Tanai Township, Myitkyina District, Kachin State, northern Myanmar.

Etymology: The species is named after Artur Michalski, a Polish amber collector (predominantly specialized in Baltic amber) who donated the specimen to the authors for scientific purposes. With the naming, authors intend to encourage collectors and traders to cooperate with scientists to reveal the palaeobiodiversity trapped in amber.

 

Péter Kóbor & Márton Szabó. 2025. A New fossil plesiomorphic Flat Bug (Aradidae) suggests widespread flower visiting in Heteroptera during the Mesozoic. Scientific Reports. 15: 30282. DOI: doi.org/10.1038/s41598-025-15559-8 [19 August 2025]

[Botany • 2025] Bakiribu waridza • A regurgitalite reveals A New filter-feeding Pterosaur (Pterosauria: Ctenochasmatidae) from the Santana Group, Northeast Brazil

 

Bakiribu waridza 

Pêgas, Aureliano, Holgado, Almeida, Santos & Ghilardi, 2025

DOI: doi.org/10.1038/s41598-025-22983-3  

Artwork by Julio Lacerda

Abstract

The Santana Group in Northeast Brazil has yielded a remarkable discovery: the first filter-feeding pterosaur from the tropics, named Bakiribu waridza gen. et sp. nov. This new taxon provides key insights into the evolutionary history and ecological diversity of Ctenochasmatidae, a clade known for its specialized feeding adaptations. Bakiribu exhibits extremely elongated jaws and dense, brush-like tooth rows, similar to Pterodaustro but distinct in tooth cross-section and spacing. Paleohistological analysis of the teeth revealed well-preserved dentine and pulp cavities. Phylogenetic analysis recovers Bakiribu as the sister taxon to Pterodaustro, forming a clade more closely related to Ctenochasma than to Gegepterus, which is reinterpreted as a non-ctenochasmatine. Regarding some specific traits such as tooth density, elongation, and count, Bakiribu is intermediate between Ctenochasma and Pterodaustro, thus partially bridging a key evolutionary gap within Ctenochasmatinae. Taphonomic features support the interpretation of the fossil assemblage as a regurgitalite. This discovery brings crucial data for understanding biogeographic dispersal and ecological specialization within Ctenochasmatinae during the Early Cretaceous, and offers rare evidence of predator-prey interactions in the Romualdo Formation paleoecosystem. Together, these findings further underscore the importance of the Araripe Basin as a window into the Early Cretaceous biodiversity.

Keywords: Pterodactyloidea, Ctenochasmatidae, Araripe basin, Romualdo formation, Paleohistology, Regurgitalite

Pterosauria Owen 1842.

Pterodactyloidea Plieninger 1901.

Ctenochasmatidae Kuhn 1967.

Ctenochasmatinae Nopcsa 1928.

Pterodaustrini Andres, Clark and Xu 2014.

Overview of the concretion containing the remains of Bakiribu waridza gen. et sp. nov. (holotype and paratype) and four associated fishes.
 A, Part (MCC 1271.1-V). B, Counterpart (MPSC 7312).
C and D, Schematic drawings of MCC 1271.1-V and MPSC 7312, respectively.

Scale bar equals 50 mm.

Bakiribu waridza gen. et sp. nov.

Diagnosis. Ctenochasmatine pterosaur with the following combination of features, including autapomorphies (marked with an asterisk): jaws extremely elongate (estimated rostral index of ~ 12–16); teeth closely packed together (interdental gaps under tooth diameter); high tooth density (17.6 teeth/cm); high tooth count (between 110 and 142 per jaw, per side, as preserved; total estimate = between 440 and 568); teeth long and slender (elongation index surpassing 1:60); acrodont-like tooth implantation on both jaws*; and tooth crowns subquadrangular in cross-section*.

Holotype. MCC 1271-Va/MPSC 7312a (Figs. 2 and 3A and B), a partial rostrum. Based on position and orientation, fragments b, c, and d most likely belong to the same individual (Fig. 3B).

Horizon and Locality. This fossil was preserved in a calcareous concretion of the Romualdo Formation, Araripe Basin, Northeast Brazil. This unit is late Aptian-early Albian in relative age31. The precise locality of this concretion is unknown, but the Romualdo Formation outcrops east-west along the Araripe Plateau between the states of Pernambuco, Ceará, and Piauí.

Etymology. The generic epithet comes from bakiribú (Kariri word for ‘comb’), in allusion to the typical comb-like dentition of ctenochasmatids. The specific epithet comes from waridzá (Kariri word for ‘mouth’). Together, the binomial name not only highlights the distinctive dental morphology of the taxon but also honors the cultural heritage of the Kariri people, Indigenous inhabitants of the region where the fossil was discovered.

Reconstruction of the type specimens of Bakiribu waridza gen. et sp. nov.
 A, close view of MCC 1271.1-V (main part). B, simplified schematic reconstruction of the holotype based on fragments a, b, c, and d. C, simplified schematic reconstruction of holotype based on fragments e, f, and g. Scale bar equals 10 mm.

Artistic reconstruction of the filter-feeding pterosaur  Bakiribu waridza gen. et sp. nov. in the Early Cretaceous Romualdo Formation environment. The spinosaurid in the background represents the putative predator that produced the regurgitalite described herein.

Artwork by Julio Lacerda.

 

R. V. Pêgas, Tito Aureliano, Borja Holgado, William B. S. Almeida, Claude L. A. Santos and Aline M. Ghilardi. 2025. A regurgitalite reveals A New filter-feeding Pterosaur from the Santana Group. Scientific Reports. 15, 37336. DOI: doi.org/10.1038/s41598-025-22983-3 [10 November 2025]