[PaleoBotany • 2025] Zosterophyllum baoyangense • The smallest Zosterophyllum plant from the Lower Devonian of South China and the divergent life-history strategies in zosterophyllopsids

 

Zosterophyllum baoyangense Huang & Xue, 

in Huang, J.-S. Wang, Y.-L. Wang, Liu, Zhao et Xue. 2025. 

 DOI: doi.org/10.1098/rspb.2024.2337

Abstract

Plants have evolved different life-history strategies to overcome limited amounts of available resources; however, when and how divergent strategies of sexual reproduction evolved in early land plants are not well understood. As one of the notable and vital components of early terrestrial vegetation, the Zosterophyllopsida and its type genus Zosterophyllum reached maximum species diversity during the Pragian (Early Devonian; ca 410.8–407.6 million years ago). Here we describe a new species, Zosterophyllum baoyangense sp. nov., based on well-preserved specimens from the Pragian-aged Mangshan Group of Duyun, Guizhou Province, China. The new plant is characterized by its small size, K-shaped branching and tiny spikes with 5–10 sporangia. This plant is most likely r-selected, completing its whole lifespan in a short time, and such a strategy contributes to reproduction in a suitable window time. In contrast, most other species of Zosterophyllum and the zosterophyllopsids on a broader scale are larger in body size and have greater investments in fertile tissues, reflected in the size and total number of sporangia. We argue that the zosterophyllopsids probably benefited from the divergence of various life-history strategies and thus constituted a major part of the Early Devonian floras.

Keywords: early land plants, Zosterophyllum baoyangense sp. nov., Early Devonian, life-history strategies

  Zosterophyllum baoyangense sp. nov. (a,b) PB203562, part and counterpart, showing a fertile axis with K-shaped branching and a terminal spike. Arrows highlight branching points. The parts indicated by arrows c and d are enlarged in (c,d), respectively; (c) K-shaped branching; (d) branching point showing a nearby protuberance (arrow); (e,f) Enlarged view of the terminal spike in (a) and (b); (g) enlarged view of the basal part of the spike in (e). Arrow points to the margin of the basal sporangium. (h) Enlargement of the distal sporangia in (f) (arrow h), showing dehiscence line (white arrow) and peripheral rim along the convex distal margin (the area between two black arrows). Scale bars: (a,b), 10 mm; (c–f), 1 mm; (g,h), 0.5 mm.

 Systematic palaeontology

Class: Zosterophyllopsida Hao & Xue [2013]

Order: Zosterophyllales Hao & Xue [2013]

Family: Zosterophyllaceae Banks [1968]

Genus: Zosterophyllum Penhallow [1892]

Type species Z. myretonianum Penhallow [1892]

Zosterophyllum baoyangense Huang & Xue sp. nov.

Specific diagnoses. Rhizome with K-shaped branching. Erect axis with tiny spikes. Axes 0.5−1.3 mm wide. Spikes, 5.8−10.8 mm high and 2.0−2.8 mm in maximum width, consisting of 5–10 sporangia that are spirally arranged. Sporangia oval to semicircular, 1.6−2.0 mm high and 0.9−1.4 mm wide, departing from axis at an acute angle by a short stalk. Thin peripheral rim ca 80 μm wide, extending along the convex distal margin and lacking thickened dehiscence mechanism.

Etymology. The specific epithet is derived from Baoyang Village, where the fossils were collected.

Holotype designated herein. PB203562 

 Artist’s restoration of part of the Early Devonian Mangshan flora, with plant communities of Zosterophyllum baoyangense sp. nov. at the front, and Teyoua antrorsa, Zosterophyllum australianum and an unnamed zosterophyllopsid to the back.

Locality and horizon. Baoyang Section, Baoyang Village, Duyun City, Guizhou Province; the lower part of the Mangshan Group; Early Devonian (Pragian; see electronic supplementary material, figure S1).

Repository. All specimens are deposited at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, China.

Pu Huang, Jia-Shu Wang, Yi-Ling Wang, Lu Liu, Jing-Yu Zhao and Jin-Zhuang Xue. 2025. The smallest Zosterophyllum plant from the Lower Devonian of South China and the divergent life-history strategies in zosterophyllopsids. Proc. R. Soc. B. 292; 20242337. DOI: doi.org/10.1098/rspb.2024.2337

 

 

[PaleoMammalogy • 2024] Nanxiongilambda yei • First Asian Paleocene pantolambdid pantodont (Mammalia) and its implications to intercontinental faunal exchange

Nanxiongilambda yei 

Quan & Wang, 2024

www.vertpala.ac.cn 

 Researchgate.net/publication/385015091

 Illustrated by Chen Yu

Pantodonta was one of the first groups of eutherians to evolve at the beginning of Cenozoic era, including the largest herbivores at that time. Pantodonta shows considerable diversity during the Paleocene and Eocene, with most of the species having been discovered in Asia and North America. Here, we report on a new pantodont, represented by lower jaws with well-preserved dentition, discovered from the Middle Paleocene Nongshan Formation of the Nanxiong Basin, Guangdong Province, China. Its unique dental and mandibular characteristics distinguish it well from any known Asian pantodont, but are quite consistent with North American taxa, especially Pantolambda and Titanoides. The new specimen is identified as Nanxiongilambda yei gen. et sp. nov., characterized by the combination of the following morphological features: thick and robust mandible with a conspicuous anteroexternal flange, high positioned condyloid process, posteriorly protruding angular process, robust but not elongated lower canines, double-rooted p1, small but distinct talonids on posterior lower premolars, talonids nearly as wide as trigonids on lower molars, and m3 with a well-developed hypoconulid and a distinct entoconid. The new discovery marks the first record of a pantolambdid pantodont outside of North America, suggesting a broader geographical distribution and intercontinental dispersal of this clade during the Paleocene. Considering the more primitive Pantolambda only found from Torrejonian to early Tiffanian NALMA (equivalent to middle-late Shanghuan to early Nongshanian ALMA), which is slightly earlier than Nanxiongilambda (early Nongshanian ALMA), pantolambdids have likely undergone a particular wave of migration from North America to Asia during the Early-Middle Paleocene. Previous researches have suggested that pantodonts had dispersed only from Asia to North America during the Early Paleocene, but our new specimen indicates the biotic dispersal may have occurred in the opposite direction. The new specimen also contributes to the renewal of the evolutionary history of pantodonts and provides further insights into the migration and dispersal of Paleocene mammals.

 Right lower jaw with cheek teeth of Nanxiongilambda yei gen. et sp. nov. (IVPP V33263, Holotype) from Nanxiong, Guangdong, China
 A. lateral view; B. medial view

Abbreviations: agp. angular process; apf. anteroposterior flange; cdp. condyloid process; cop. coronoid process; maf. masseteric fossa; mdf. mandibular foramen; mf. mental foramina

 Lower jaws with teeth of Nanxiongilambda yei gen. et sp. nov. (IVPP V33263, Holotype) from Nanxiong, Guangdong, China
A. left and right mandible in occlusal view; B. left mandible in lateral view; C. left mandible in medial view; D. right cheek teeth (p2-p4 and m2-m3) in occlusal view; E. left cheek teeth (p1-m1) in occlusal view

Abbreviations: end. entoconid; hyd. hypoconid; hyld. hypoconulid; med. metaconid; pad. paraconid; prd. protoconid; tad. talonid

Head reconstruction of Nanxiongilambda yei gen. et sp. nov.
Nanxiongilambda from the Middle Paleocene Nongshan Formation of the Nanxiong Basin, Guangdong Province, China is a pantolambdid, belonging to the order Pantodonta, an extinct group of “archaic ungulates”. Members of Pantolambdidae were previously only known from the lower–middle Paleocene in North America. This finding extends the geographical distribution of Pantolambdidae. Nanxiongilambda yei represents the first known Asian Cenozoic mammal with reliable North American affinity prior to the Late Paleocene, which indicates a particular wave of migration from North America to Asia during the late Early-early Middle Paleocene.

(Illustrated by Chen Yu).

QUAN Shuo-Shuo and WANG Yuan-Qing. 2024. First Asian Paleocene pantolambdid pantodont (Mammalia) and its implications to intercontinental faunal exchange. Vertebrata Palasiatica. 62(4); 291-312.  DOI: 10.19615/j.cnki.2096-9899.240829  

https://www.vertpala.ac.cn/EN/10.19615/j.cnki.2096-9899.240829

  Researchgate.net/publication/385015091_First_Asian_Paleocene_pantodont_Mammalia

[PaleoOrnithology • 2023] Anachronornis anhimops • Basal Anseriformes from the Early Paleogene of North America and Europe

 Anachronornis anhimops 

Houde, Dickson & Camarena, 2023 

   

 DOI:  10.3390/d15020233  

Abstract

We describe nearly complete skeletons of basal Anseriformes from the Latest Paleocene to the early Eocene of North America and Europe. Collectively, these birds appear to be representative of anseriforms near the divergence of Anhimae and Anseres, but their exact positions relative to these clades remains uncertain. A new family, Anachronornithidae nov. fam., is erected on the basis of one of these, Anachronornis anhimops nov. gen., nov. gen. et sp., to which the others cannot be confidently assigned. The new fossils augment a growing collection of early Pan-Anseriformes, which in their diversity do not paint an unambiguous picture of phylogeny or character state evolution on the path to or within crown-Anseriformes. Anachronornis nov. gen. is similar in some aspects of both cranial and postcranial anatomy to other well-represented early Paleogene Anseriformes and members of Anseres, such as Presbyornis Wetmore, 1926. However, it exhibits a more landfowl-like bill, like that of Anhimae and unlike the spatulate bill of Anseres. Additional specimens of similar basal Anseriformes of uncertain affinities from the early Eocene of North America and Europe further complicate interpretation of character state polarity due to the mosaicism of primitive and derived characters they exhibit.  

Keywords: Anseriformes; Anseres; Anhimidae; Anachronornithidae; Presbyornis; Anatalavis; Nettapterornis; Anachronornis; Danielsavis

 

  Holotype of Anachronornis anhimops nov. gen. et sp. (USNM 496700):
skull, ventral (A), dorsal (B), right lateral (C), right lateral in matrix (D), caudal (E); mandible with heavy gauge wire glued to medial side of right dentary, right lateral (F), dorsal (G), oblique caudomedial aspect of right side (K), right caudal (O); quadrates, left lateral (H), right lateral (I), left medial (L), right medial (M); basihyal (Q), costal fragment with uncinate process (R), left palatine (S), right thoracic vertebrae (T). Quadrate (USNM 496701; Anseriformes fam. incertae sedis): right lateral (J), right medial (N).
Holotype of Danielsavis nazensis nov. gen. et sp. (NMS.Z.2021.40.1): right caudal mandible (P).

All but (D,P) are coated with ammonium hydroxide. Scale bar 1 cm.

 Class Aves Linnaeus, 1758

Order Anseriformes Wagler, 1831

Family Anachronornithidae nov. fam. Houde, Dickson, and Camarena

 

Included genus Anachronornis nov. gen.

Diagnosis: Anachronornithidae nov. fam. is distinguished from all known Anhimidae and Anseres by a lack of unambiguous synapomorphies diagnosing those respective clades and in many respects is intermediate between the two.

Anachronornis nov. gen. Houde, Dickson, and Camarena

 

Etymology: From the Greek ἀναχρονισμός, out of time, and ὄρνις, bird, alluding to the unexpectedly late occurrence of what may be, or may be close to, the most recent common ancestor of the two crown-anseriform lineages, Anhimae and Anseres.

Type and only known species: Anachronornis anhimops nov. gen. et sp.

Occurrence: Late Paleocene of North America.

Diagnosis: As for the family, by monotypy. (Full account of all putative apomorphies by dataset in Supplemental Materials and Supplementary Appendices A3, B2, C2, D2, F3, G6 and G7).

Anachronornis anhimops nov. gen. et sp. Houde, Dickson, and Camarena

Etymology: From the generic name Anhima, a screamer, and ops (Greek, face, countenance, appearance of the face). The name is intended to refer to the screamer-like bill and appearance of the head, particularly like that of Anhima in which the supraorbital region may be somewhat narrower than in Chauna.

 Peter Houde, Meig Dickson and Dakota Camarena. 2023. Basal Anseriformes from the Early Paleogene of North America and Europe. Diversity. 15(2); 233. DOI:  10.3390/d15020233  

 

  

[PaleoBotany • 2023] Bauhinia tibetensis • The Oldest Fossil Record of Bauhinia s.s. (Fabaceae) from the Tibetan Plateau sheds light on its Evolutionary and Biogeographic Implications

  

 Bauhinia tibetensis Y. Gao & T. Su, 
 

in Gao, Song, Deng, Chen, Liu, ... et Su, 2023. 

DOI: doi.org/10.1080/14772019.2023.2244495 

english.CAS.cn

Abstract

Bauhinia s.s. is a large genus in the family Fabaceae, but its evolutionary and biogeographical history is still unclear due to the scarcity of fossil records compared to the highly diverse modern species in pantropic regions. Here, we report the earliest fossil record of Bauhinia s.s., namely Bauhinia tibetensis Y. Gao et T. Su sp. nov., based on leaves from the latest Paleocene of the southern Tibetan region. Combined with palaeoecological niche simulations and ancestral state reconstruction, the new fossils suggested a Paleocene origin of Bauhinia s.s. in the Afrotropical realm that subsequently dispersed to the Neotropical and Indomalayan realms. Bauhinia tibetensis belongs to the Asian clade of Bauhinia s.s. that reached the southern Tibetan region from the Afrotropical realm via the Kohistan-Ladakh Island Arc in the early Paleocene. This clade spread to south-eastern China during the Oligocene and entered northern India during the Neogene or earlier. The discovery of the oldest Bauhinia s.s. from what is now the southern Tibetan Plateau updates our understanding of the biogeographical history of this genus and demonstrates that the Kohistan-Ladakh Island Arc is an ancient corridor for floristic interchange between Africa and India.

Keywords: Bauhinia s.s., biogeography, diversification, Paleocene, leaf fossil, palaeoecological niche simulations

 

Yi Gao, Ai Song, Wei-Yu-Dong Deng, Lin-Lin Chen, Jia Liu, Wei-Cheng Li, Gaurav Srivastava, Robert A. Spicer, Zhe-Kun Zhou and Tao Su. 2023. The Oldest Fossil Record of Bauhinia s.s. (Fabaceae) from the Tibetan Plateau sheds light on its Evolutionary and Biogeographic Implications. Journal of Systematic Palaeontology. 21(1); 2244495. DOI: doi.org/10.1080/14772019.2023.2244495

 english.CAS.cn/newsroom/research_news/life/202311/t20231101_467162.shtml

  x.com/AsiaPaleofloras/status/1715100959364317389

[PaleoMammalogy • 2024] Militocodon lydae • A New periptychid Mammal (Mammalia : Periptychidae) from the lower Paleocene Denver Formation of Colorado (Corral Bluffs, El Paso County)

Militocodon lydae

Weaver, Crowell, Chester & Lyson, 2024

DOI: 10.1007/s10914-024-09716-5

  facebook.com: Luke Weaver 

 Researchgate.net/publication/380211959

Artwork by Andrey Atuchin

Abstract

The Periptychidae, an extinct group of archaic ungulates (‘condylarths’), were the most speciose eutherian mammals in the earliest Paleocene of North America, epitomizing mammalian ascendency after the Cretaceous–Paleogene (K–Pg) mass extinction. Although periptychids are mostly known from fragmentary gnathic remains, the Corral Bluffs area within the Denver Basin, Colorado, has yielded numerous exceptionally well-preserved mammalian fossils, including periptychids, from the earliest Paleocene. Here we describe a partial cranium and articulated dentaries plus an additional unassociated dentary fragment of a small-bodied (~273–455 g) periptychid from ca. 610 thousand years after the K–Pg mass extinction (Puercan 2 North American Land Mammal ‘age’) at Corral Bluffs. Based on these new fossils we erect Militocodon lydae gen. et sp. nov. The dentition of M. lydae exhibits synapomorphies that diagnose the Conacodontinae, but it is plesiomorphic relative to Oxyacodon, resembling putatively basal periptychids like Mimatuta and Maiorana in several dental traits. As such, we interpret M. lydae as a basal conacodontine. Its skull anatomy does not reveal clear periptychid synapomorphies and instead resembles that of arctocyonids and other primitive eutherians. M. lydae falls along a dental morphocline from basal periptychids to derived conacodontines, which we hypothesize reflects a progressive, novel modification of the hypocone to enhance orthal shearing and crushing rather than grinding mastication. The discovery and thorough descriptions and comparisons of the partial M. lydae skull represent an important step toward unraveling the complex evolutionary history of periptychid mammals.

Keywords: Archaic ungulates, Condylarths, Eutherians, Periptychidae, Puercan

Holotype of Militocodon lydae gen. et sp. nov. (DMNH EPV.136181) in right (a) and left (b) lateral views. Scale bar equals 2 cm

MAMMALIA Linnaeus, 1758

EUTHERIA Gill, 1872

?UNGULATA Linnaeus, 1758

PERIPTYCHIDAE Cope, 1882

CONACODONTINAE Archibald, Schoch, and Rigby, 1983

Militocodon gen. nov.

Etymology. In honor of Sharon Milito, for her dedication to paleontology and education in the Denver Basin and for finding referred specimen DMNH EPV.103390.

Distribution. Puercan 2 of the Denver Formation, D1 Sequence at Corral Bluffs (El Paso County, Colorado).

Diagnosis. Resembling the Conacodontinae (sensu Archibald et al. 1983b) in: M1–3 hypocone large and lingually expanded; protocone absent on P3. Resembling Oxyacodon (sensu Archibald et al. 1983a) in: premolars slightly inflated but P/p4 shorter or subequal in length to M/m1; para- and metastylar lobes on M1–3 more buccally expanded than in Alticonus, Ampliconus, Miniconus, Tinuviel, Anisonchus, Conacodon, Haploconus, and Hemithlaeus; metacingulum continuous with metastylar region; paraconule absent with postparaconule wing meeting preprotocrista near apex of protocone; hypocone expanded lingually beyond the protocone; paraconid on p4 small, situated near the base of the crown; narrow buccal cingulid present on lower molars and lingual cingulid absent on lower premolars and molars. Differing from Oxyacodon in: greater expansion of para- and metastylar lobes on P4, with the former also projecting farther mesially; hypocone lingual face more vertically oriented on M2–3, not sloping prominently lingually; hypocone apex distinctly distal to protocone apex, especially on M2, resulting in a more rectangular (rather than triangular) occlusal outline; paraconid on m1–3 not closely appressed to metaconid, resulting in a mesiolingually open trigonid basin; trigonid taller relative to talonid, due in part to a taller protoconid.

Militocodon lydae sp. nov.

Etymology. In honor of Lyda Hill, a longtime champion of Colorado Springs and key supporter of post-K–Pg recovery research at the Denver Museum of Nature & Science.

Holotype. DMNH EPV.136181, partial skull, including posterior maxillae and dentaries, RP/p4–M/m3 and LP/p3–M/m3, and partial neuro- and basicranium.

Lucas N. Weaver, Jordan W. Crowell, Stephen G. B. Chester and Tyler R. Lyson. 2024. Skull of A New periptychid Mammal from the lower Paleocene Denver Formation of Colorado (Corral Bluffs, El Paso County). Journal of Mammalian Evolution. 31, 16. DOI: 10.1007/s10914-024-09716-5

  facebook.com/LukeWeaver731/posts/7798559490183707

 Researchgate.net/publication/380211959_a_new_periptychid_mammal_from_Paleocene_Denver_Formation_of_Colorado

[PaleoOrnithology • 2023] Kumimanu fordycei & Petradyptes stonehousei • Largest-known Fossil Penguin provides insight into the early Evolution of sphenisciform Body Size and Flipper Anatomy

 

 Kumimanu fordycei & Petradyptes stonehousei

 Ksepka, Field, Heath, Pett, Thomas, Giovanardi & Tennyson, 2023

DOI: 10.1017/jpa.2022.88

otago.ac.nz

Life reconstructions by Simone Giovanardi.

 twitter.com/GiovaFavazzi

Abstract

Recent fossil discoveries from New Zealand have revealed a remarkably diverse assemblage of Paleocene stem group penguins. Here, we add to this growing record by describing nine new penguin specimens from the late Paleocene (upper Teurian local stage; 55.5–59.5 Ma) Moeraki Formation of the South Island, New Zealand. The largest specimen is assigned to a new species, Kumimanu fordycei n. sp., which may have been the largest penguin ever to have lived. Allometric regressions based on humerus length and humerus proximal width of extant penguins yield mean estimates of a live body mass in the range of 148.0 kg (95% CI: 132.5 kg–165.3 kg) and 159.7 kg (95% CI: 142.6 kg–178.8 kg), respectively, for Kumimanu fordycei. A second new species, Petradyptes stonehousei n. gen. n. sp., is represented by five specimens and was slightly larger than the extant emperor penguin Aptenodytes forsteri. Two small humeri represent an additional smaller unnamed penguin species. Parsimony and Bayesian phylogenetic analyses recover Kumimanu and Petradyptes crownward of the early Paleocene mainland NZ taxa Waimanu and Muriwaimanu, but stemward of the Chatham Island taxon Kupoupou. These analyses differ, however, in the placement of these two taxa relative to Sequiwaimanu, Crossvallia, and Kaiika. The massive size and placement of Kumimanu fordycei close to the root of the penguin tree provide additional support for a scenario in which penguins reached the upper limit of sphenisciform body size very early in their evolutionary history, while still retaining numerous plesiomorphic features of the flipper.

 

Life reconstructions of Kumimanu fordycei and Petradyptes stonehousei,

by Simone Giovanardi. twitter.com/GiovaFavazzi

Skeletal reconstructions of (left to right) Kumimanu fordycei, Petradyptes stonehousei, and Aptenodytes forsteri a modern emperor penguin.

Daniel T. Ksepka, Daniel J. Field, Tracy A. Heath, Walker Pett, Daniel B. Thomas, Simone Giovanardi and Alan J.D. Tennyson. 2023. Largest-known Fossil Penguin provides insight into the early Evolution of sphenisciform Body Size and Flipper Anatomy. Journal of Paleontology. First View , pp. 1 - 20

DOI: 10.1017/jpa.2022.88

UUID: zoobank.org/15b1d5b2-a5a0-4aa5-ba0a-8ef3b8461730

 www.otago.ac.nz/otagobulletin/news/otago0241045.html 

 twitter.com/GiovaFavazzi/status/1623393800134754304

[Paleontology • 2021] Sindhochelys ragei • First Report of A Bothremydid Turtle (Pleurodira: Bothremydidae) from the early Paleocene of Pakistan, Systematic and Palaeobiogeographic Implications

 Sindhochelys ragei

 Lapparent De Broin, Métais, Bartolini, Brohi, Lashari, Marivaux, Merle, Warar & Solangi, 2021

 sciencepress.mnhn.fr 

We report the discovery of remains of a large chelonian from the base of the early Paleocene Khadro Formation exposed in the Ranikot Fort area (Ranikot Group, Sindh Province, Southern Pakistan). This formation already yielded the snake Gigantophis Andrews, 1901, studied by our friend Jean-Claude Rage. The chelonian specimens consist of a large carapace and a shell fragment of Bothremydidae, a family of Gondwanan origin. A new genus and species, Sindhochelys ragei n. gen., n. sp. is identified from the first specimen and named in honor of Jean-Claude Rage. It is the first report of a Bothremydidae in Southern Pakistan. Its affinities with Cretaceous and Paleocene representatives of the family are discussed. The association of characters such as the shape of the shell, anterior plastral scute pattern and strongly marked decoration characterize the taxon and, despite some similarities, allows excluding close phylogenetic affinities with Taphrosphyini and Carteremys group; other well-documented bothremydids are also excluded. The shell fragment, also strongly decorated, is left undetermined. The discovery of two new littoral bothremydid specimens in the early Paleocene of Pakistan fills a geographic and stratigraphic gap in our knowledge of the family, which is known since the continental early Cretaceous of Africa, diversifying in the world up to the Miocene deposits of the Neotethys. A particular diversification during the Maastrichtian-Paleocene is recognized along the neotethyan coasts, and occasional dispersals across this ocean were possible. Sindhochelys ragei n. gen., n. sp. may have colonized the Indian subcontinent by this time, or may represent an older diversification before the Gondwana breakup.

KEYWORDS: Bothremydidae, Southern Pakistan, geology, Pelomedusoides, Gondwana, Neotethys, new genus, new species

Sindhochelys ragei n. gen., n. sp.

 

France de Lapparent De Broin, Grégoire Métais, Annachiara Bartolini, Imdad Ali Brohi, Rafiq A. Lashari, Laurent Marivaux, Didier Merle, Mashooque Ali Warar and Sarfraz H. Solangi. 2021. First  Report of A Bothremydid Turtle, Sindhochelys ragei n. gen., n. sp., from the early Paleocene of Pakistan, Systematic and Palaeobiogeographic Implications. GEODIVERSITAS. 43(25); 1341-1363. [This article is a part of the thematic issue Memorial Jean-Claude Rage: A life of paleo-herpetologist]

 sciencepress.mnhn.fr/en/periodiques/geodiversitas/43/25

 twitter.com/plazi_species/status/1471014928639270920

[Paleontology • 2021] Palatobaena knellerorum • A New Baenid Turtle (Testudines: Baenidae) from the lower Paleocene (Danian) Denver Formation of south-central Colorado, U.S.A.

 Palatobaena knellerorum

 Lyson, Petermann, Toth, Bastien & Miller, 2021

  DOI: 10.1080/02724634.2021.1925558

 twitter.com/DenverMuseumNS 

Illustration by Andrey Atuchin

ABSTRACT

Baenidae are the most diverse clade of turtles from the latest Cretaceous and earliest Paleogene of North America. Palatobaena species have a distinctive cranial bauplan within baenid turtles and we herein describe a new species, P. knellerorum, based on a complete cranium from the lower Paleocene Denver Formation in the Denver Basin, Colorado. Palatobaena knellerorum differs from other Palatobaena species in the extreme degree of its dorsally oriented orbits, as well as the presence of a broad pentagonal midline crest formed by the supraoccipital and parietals. It can be further diagnosed from other species of Palatobaena by the following unique combination of characters: having a broadly rounded cranium, presence of upper temporal emargination that extends well anterior to the otic chamber, a broad exposure of the supraoccipital on the dorsal skull roof, a broadly rounded ‘tongue groove’ between the maxillae and premaxillae, and a deeply emarginated nasal region that exposes the underlying premaxillae in dorsal view. Palatobaena knellerorum most closely resembles the Maastrichtian/Danian taxon Palatobaena cohen and the Danian taxon P. bairdi. A phylogenetic analysis places P. knellerorum as sister to P. bairdi, and these taxa are sister to P. cohen. Palatobaena knellerorum overlaps in time with P. cohen, but the two are separated geographically with P. knellerorum restricted to the Denver Basin and P. cohen restricted to the Williston Basin. Cranial anatomical data and sedimentological data suggest Palatobaena spp. were bottom dwelling turtles living in shallow water environments that used a putative proboscis to prey upon freshwater-shelled invertebrates.

 Palatobaena knellerorum sp. nov.

Tyler R. Lyson, Holger Petermann, Natalie Toth, Salvador Bastien and Ian M. Miller. 2021. A New Baenid Turtle, Palatobaena knellerorum sp. nov., from the lower Paleocene (Danian) Denver Formation of south-central Colorado, U.S.A. Journal of Vertebrate Paleontology. e1925558. DOI: 10.1080/02724634.2021.1925558

 twitter.com/DenverMuseumNS/status/1411000221723734019 

[Paleontology • 2021] Plastomenus joycei • A New Plastomenid Trionychid Turtle (Testudines: Plastomenidae) from the earliest Paleocene (Danian) Denver Formation of south-central Colorado, U.S.A.

 Plastomenus joycei

Lyson, Petermann & Miller, 2021

 DOI: 10.1080/02724634.2021.1913600   

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ABSTRACT

North American soft-shelled turtles, including trionychines and plastomenids, are incredibly abundant in latest Cretaceous through earliest Paleocene sediments. Here we describe a new species of plastomenid turtle, Plastomenus joycei, based on a nearly complete early Danian skeleton from the Denver Formation in the Denver Basin, Colorado. Plastomenus joycei is differentiated from all other plastomenid turtles based on the presence of large eighth costals that are much longer than wide, sinusoidal raised ridges on the carapace, flat posterior edge of the carapace, spike-like epiplastra that lack callosities, a broad entoplastron that lacks a callosity, hyoplastra with two lateral processes, presence of metaplastically ossified hyoplastral shoulders (i.e., anteriorly protruding lappets), and a broad midline contact between the hypo- and xiphiplastra. Plastomenus joycei broadly resembles the Cretaceous Gilmoremys spp. and the Eocene Plastomenus thomasii and exhibits intermediate morphology between the two, most notably in the degree of ossification of the plastron. The increase in plastral ossification, as well as a decrease in overall size and an increase in the doming of the shell, co-occurs with the Cretaceous–Paleogene mass extinction and these morphological changes may be in response to an increase in mammalian predators during the early Paleogene. Plastomenus joycei is most commonly found in riverine sandstone sediments and is hypothesized to be a riverine turtle.

SYSTEMATIC PALEONTOLOGY

TESTUDINES Batsch, 1788 

(sensu Joyce, Parham, Anquetin, Claude, Danilov, Iverson, Kear, Lyson, Rabi, and Sterli, 2020)

PAN-TRIONYCHIDAE Joyce, Anquetin, Cadena, Claude, Danilov, Evers, Ferrera, Gentry, Georgalis, Lyson, Perez-Garcia, Rabi, Sterli, Vitek, and Parham, 2021

PLASTOMENIDAE Hay, 1908 

(sensu Joyce, Anquetin, Cadena, Claude, Danilov, Evers, Ferrera, Gentry, Georgalis, Lyson, Perez-Garcia, Rabi, Sterli, Vitek, and Parham, 2021)

PLASTOMENUS Cope, 1873

Type Species—Trionyx thomasii Cope, 1872.

PLASTOMENUS THOMASII (Cope, 1873)

PLASTOMENUS VEGETUS, nov. comb. (Gilmore, 1919) 

 

 Plastomenus joycei, sp. nov., DMNH EPV.95454, holotype, 
 ventral view. 

PLASTOMENUS JOYCEI, sp. nov. 

 

Etymology—The eponym ‘joycei’ is named in honor of W. G. Joyce, prominent turtle paleontologist and friend and colleague to T. R. Lyson.

 

Tyler R. Lyson, Holger Petermann and Ian M. Miller. 2021. A New Plastomenid Trionychid Turtle, Plastomenus joycei, sp. nov., from the earliest Paleocene (Danian) Denver Formation of south-central Colorado, U.S.A. Journal of Vertebrate Paleontology. e1913600. DOI: 10.1080/02724634.2021.1913600  

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[Paleontology • 2020] Laurasichersis relicta • Surviving the Cretaceous-Paleogene Mass Extinction Event: A Terrestrial Stem Turtle in the Cenozoic of Laurasia

Laurasichersis relicta Pérez-García, 2020

DOI: 10.1038/s41598-020-58511-8 

Illustration: José Antonio Peñas

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Abstract

Findings of terrestrial stem turtles are not uncommon at Mesozoic continental sites in Laurasia, especially during the Upper Cretaceous. Thus, the record of several lineages is known in uppermost Cretaceous ecosystems in North America (Helochelydridae), Europe (Helochelydridae and Kallokibotion) and Asia (Sichuanchelyidae). No terrestrial stem turtle had been described in Laurasia after the Cretaceous-Paleogene mass extinction event. Thus, the only representatives described in the Cenozoic record worldwide corresponded to forms from southern Gondwana, where some of them survived until the Holocene. A bizarre terrestrial stem turtle from the upper Thanetian (upper Paleocene) of Europe is described here: Laurasichersis relicta gen. et sp. nov. Despite its discovery in France, in Mont de Berru (Marne), this Laurasian taxon is not recognized as a member of a European clade that survived the Cretaceous-Paleogene extinction event. It belongs to Sichuanchelyidae, a hitherto exclusively Asian Mesozoic group, known from the Middle Jurassic. Finds at the Belgian site of Hainin (Hainaut) show that this dispersion from Asia and the occupation of some niches previously dominated by European Mesozoic terrestrial stem forms had already taken place a few million years after the mass extinction event, at the end of the lower Paleocene.

Systematic paleontology

Testudinata Klein, 1760

Mesochelydia Joyce, 2017

Perichelydia Joyce, 2017

Sichuanchelyidae Tong et al., 2012

Laurasichersis relicta gen. et sp. nov.

Figure 1: Elements of the carapace of the stem turtle (Sichuanchelyidae) Laurasichersis relicta gen. et sp. nov., from the upper Thanetian (upper Paleocene) of Mont de Berru (Marne, France). (A,B), carapace plates corresponding to several individuals, in dorsal (A) and ventral (B) views: nuchal MNHN.F BR13461; neurals (anterior to posterior) MNHN.F BR13458, MNHN.F BR17487, MNHN.F BR13710, MNHN.F BR13459; right costals (anterior to posterior) MNHN.F BR13001, MNHN.F BR13620, MNHN.F BR2785, MNHN.F BR18001, MNHN.F BR13637, MNHN.F BR13628; left costals (anterior to posterior) MNHN.F BR13624, MNHN.F BR4188; right peripherals (anterior to posterior) MNHN.F BR13604, MNHN.F BR18000, MNHN.F BR13611, MNHN.F BR13468, MNHN.F BR15098, MNHN.F BR13610; left peripherals (anterior to posterior) MNHN.F BR13603, MNHN.F BR18002, MNHN.F BR13595, MNHN.F BR13465, MNHN.F BR13608, MNHN.F BR2758, MNHN.F BR4180, MNHN.F BR13480, MNHN.F BR13467. The anterior or posterior views of the peripherals are also shown in A. Scale bars equal 1 cm. For the identification of each element see Fig. 4A. (C,D), nuchal MNHN.F BR13669, in dorsal (C) and ventral (D) views. (E–H), visceral view of the the third (right) to the sixth (left) bridge peripherals MNHN.F BR13622, MNHN.F BR13623, MNHN.F BR18002 and MNHN.F BR18000. (I,J), details of the outer surface of the neural MNHN.F BR13459 (I) and costal MNHN.F BR13579 (J).

Abbreviations for the plates (in lowercase and normal type): c, costal; n, neural; nu, nuchal; p, peripheral. Abbreviations for the scutes (in uppercase and in bold type): CE, cervical; M, marginal; PL, pleural; V, vertebral.

Figure 4: Reconstruction of the shell of stem turtle (Sichuanchelyidae) Laurasichersis relicta gen. et sp. nov., from the upper Thanetian (upper Paleocene) of Mont de Berru (Marne, France). (A), dorsal view of the carapace. (B), ventral view of the plastron. Abbreviations for the plates (in lowercase and normal type): c, costal; ent, entoplastron; ep, epiplastral element; hp, hypoplastron; hy, hyoplastron; ms, mesoplastron; n, neural; nu, nuchal; p, peripheral; py, pygal; spy, suprapygal; xi, xiphiplastral element.

Abbreviations for the scutes (in uppercase and in bold type): AB, abdominal; AN, anal; AX, axillar; CE, cervical; EG, extragular; FE, femoral; GU, gular; HU, humeral; IG, inguinal; M, marginal; PC, pectoral; PL, pleural; V, vertebral.

Locality and Horizon: Mouras quarry, Mont de Berru, Berru, Marne, France. Sables de Bracheux Formation, Franco-Belgian Basin. MP6a, upper Thanetian, upper Paleocene.

Etymology: The generic name is composed by Laurasi-, referring to Laurasia, where this taxon comes from; and –chersis, a Latinized word of Greek origin (Χέρσος) which means “land or dry land”, following the criteria used to establish the generic names of some other terrestrial stem turtles. The specific name refers to the fact that the new taxon is a vestige of Mesozoic fauna, being the only known Laurasian post-Mesozoic terrestrial stem turtle.

Diagnosis: Sichuanchelyid defined by the following characters exclusive within this clade: dorsally directed distal margin of the anterior and middle peripherals, and antero-lateral margins of the nuchal; slightly wider than long nuchal; high bridge peripherals; second to fourth vertebrals narrower than the first one, and than the second and third pleurals; concave anterior plastral margin; epiplastra divided into four elements, acquiring an exclusive morphology; supernumerary xiphiplastra, divided into two elements; humeral-pectoral sulcus at the level of the axillary notch; absence of a complete inframarginal series, but presence of axillar and inguinal scutes; anterior and posterior pairs of ventral foramina for the carotids closer to each other than between the foramina that form each pair. This sichuanchelyid shows the following unique character combination: shell size greater than 60 cm; second costal as long as the first; absence of contact and long distance between the nuchal postero-lateral end and the second peripherals; first vertebral wider than the nuchal; contact of the first vertebral with the second marginals; pleural-marginal sulci on the proximal region of the peripherals; anterior end of the axillary buttress reaching the anterior half of the third peripherals; absence of plastral fontanelles; absence of strongly interfingered plastral contacts; supernumerary epiplastra; long epiplastral symphysis relative to the entoplastron length; gulars overlapping the antero-medial entoplastral area; wide exposure of the squamosals on the skull table; absence of palatal teeth; absence of ventral exposure of the prootics; narrow and deep depression between the tubercula basioccipitale; short basicranium in relation to its width; absence of cleithrum processes.

Figure 8: Calibrated cladogram corresponding to the cladistic analysis performed here (4500 most parsimonious trees, length of 943 steps, CI = 0.316, RI = 0.778, RC = 0.246), in which the position of all representatives of Perichelydia (sensu3) is shown, as well as that of the crown group Testudines. This distribution is based on the strict consensus tree, except in the case of the clade Meiolaniformes, which is obtained in the majority rule tree (67%). The paleobiogeographic distribution of each taxon is indicated. Bremer support values are shown.

Adán Pérez-García. 2020. Surviving the Cretaceous-Paleogene Mass Extinction Event: A Terrestrial Stem Turtle in the Cenozoic of Laurasia. Scientific Reports. 10: 1489. DOI: 10.1038/s41598-020-58511-8 

Researchgate.net/publication/338919986_A_terrestrial_stem_turtle_in_the_Cenozoic_of_Laurasia

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One single primitive turtle resisted mass extinction in the northern hemisphere

https://www.agenciasinc.es/en/News/One-single-primitive-turtle-resisted-mass-extinction-in-the-northern-hemisphere