[PaleoIchthyology • 2025] Sphyragnathus tyche • A New predatory Actinopterygian from the Tournaisian of Nova Scotia provides insight into the Evolution of Actinopterygian Feeding

 

Sphyragnathus tyche

Wilson, Mansky & Anderson, 2025

 DOI: doi.org/10.1080/02724634.2025.2498453

ABSTRACT

The Devonian–Carboniferous transition represents a fundamental shift in vertebrate faunal composition and ocean ecology. Tournaisian-aged outcrops of the Horton Bluff Formation from Blue Beach, Nova Scotia capture this moment and yield a diverse fauna of actinopterygians and other vertebrates. Here, we report an actinopterygian mandible preserved in 3D, representing a new genus and species, Sphyragnathus tyche. This mandible is elongate, deeply curved, and bears a primary dentition of heterodont fangs. Actinopterygian identity is established by the characteristic ornamentation, dentition, and overall mandible construction observed in the specimen. Analysis of the relationship between mandible and body length in Paleozoic actinopterygians establishes S. tyche as a relatively large actinopterygian. Mandible length, curvature, and fang morphology combine to produce a functionally differentiated dentition with distinct regions for prey capture and prey processing. Comparison with modern actinopterygians places S. tyche as a back-fanged macrodont, distinguishing it from front-fanged macrodont actinopterygians of the Late Devonian. This earliest known instance of back-fanged macrodonty in the actinopterygian fossil record provides further evidence of actinopterygian morphological differentiation post-Devonian and implies experimentation in feeding mode. Apparent changes in feeding mode are underscored by analysis of stress distribution across the dentition of Devonian front-fanged macrodont actinopterygians and S. tyche. Although this specimen is compatible with a previous ‘head-first’ model of morphological diversification in early Carboniferous actinopterygians, we argue that a ‘feeding-first’ model is a better fit.

 

  Sphyragnathus tyche sp. nov. 

Conrad D. Wilson, Chris F. Mansky and Jason S. Anderson. 2025. A New predatory Actinopterygian from the Tournaisian of Nova Scotia provides insight into the Evolution of Actinopterygian Feeding. Journal of Vertebrate Paleontology. e2498453. DOI: doi.org/10.1080/02724634.2025.2498453  [18 Jun 2025]

[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

 

 

[PaleoIchthyology • 2022] Langlieria smalingi • Second Species of Langlieria (Sarcopterygii: Tristichopteridae) from the Upper Devonian Catskill Formation of Pennsylvania, U.S.A., and A New Phylogenetic Consideration of Tristichopteridae

Langlieria smalingi

Downs & Daeschler, 2022

DOI: 10.1635/053.167.0115 

 

Abstract

A new species of Langlieria is described from the Upper Devonian (Frasnian) Irish Valley Member of the Catskill Formation. The type material was collected from a road cut exposure on the north side of the westbound lanes of Pennsylvania Route 322 west of Port Matilda, Centre County, Pennsylvania, U.S.A. The new species of Langlieria, the second from the Catskill Formation, is represented by high quality cranial material including parietal and postparietal shields, cheek, principal gular, and lower jaw; fin material; and body scales. The new species is the fourth tristichopterid to be described from the Catskill Formation (after Hyneria lindae, Langlieria radiatus, and Eusthenodon bourdoni) and the first from the Irish Valley Member. It is also the first species of Langlieria with a known record in the Frasnian. Sedimentological and stratigraphic data suggest that the discovery site represents a distal, tide-dominated location within the Catskill Delta system with a greater marine influence than has been reconstructed for the previously described Catskill Formation tristichopterids. A new phylogenetic analysis of Tristichopteridae is presented that is the first to include the new species of Langlieria described here and E. bourdoni from the Cogan House Exit Ramp locality (Famennian, Duncannon Member) along U.S. Route 15/Interstate 99. The 50% majority-rule consensus tree from the analysis supports a highly-nested clade of tristichopterids that includes all of the considered species from the Famennian, with the exception of Heddleichthys dalgleisiensis, and additionally includes the Frasnian Langlieria species that is described here.

Langlieria smalingi

Jason P. Downs and Edward B. Daeschler. 2022. Second Species of Langlieria (Tristichopteridae, Sarcopterygii) from the Upper Devonian Catskill Formation of Pennsylvania, U.S.A., and A New Phylogenetic Consideration of Tristichopteridae. Proceedings of the Academy of Natural Sciences of Philadelphia. 167(1); 241-260. DOI: 10.1635/053.167.0115 

 

NEW SPECIES OF ANCIENT FISH DISCOVERED ALONG PENNSYLVANIA ROADSIDE

newsblog.drexel.edu/2022/04/26/new-species-of-ancient-fish-discovered-along-pennsylvania-roadside/

[PaleoIchthyology • 2024] Ngamugawi wirngarri • A Late Devonian coelacanth reconfigures Actinistian Phylogeny, Disparity, and Evolutionary Ddynamics

 

Ngamugawi wirngarri 

Clement, Cloutier, Lee, King, Vanhaesebroucke, Bradshaw, Dutel, Trinajstic & Long, 2024 

DOI: 10.1038/s41467-024-51238-4

Abstract

The living coelacanth Latimeria (Sarcopterygii: Actinistia) is an iconic, so-called ‘living fossil’ within one of the most apparently morphologically conservative vertebrate groups. We describe a new, 3-D preserved coelacanth from the Late Devonian Gogo Formation in Western Australia. We assemble a comprehensive analysis of the group to assess the phylogeny, evolutionary rates, and morphological disparity of all coelacanths. We reveal a major shift in morphological disparity between Devonian and post-Devonian coelacanths. The newly described fossil fish fills a critical transitional stage in coelacanth disparity and evolution. Since the mid-Cretaceous, discrete character changes (representing major morphological innovations) have essentially ceased, while meristic and continuous characters have continued to evolve within coelacanths. Considering a range of putative environmental drivers, tectonic activity best explains variation in the rates of coelacanth evolution.

 

Ngamugawi wirngarri 
A, B ‘Part a’ of WAM 09.6.148 (holotype) shown in left dorsolateral view and skull close up in left lateral view. C ‘Part b’ of WAM 09.6.148 (holotype) showing all exposed elements; D partial braincase of NMV P231504 (paratype) shown in right lateral view; E cleithrum of NMV P231504 (paratype) in mesial and lateral view; F, G skull reconstruction in dorsal and left lateral view.

Abbreviations: Ang angular, Cl cleithrum, Clv clavicle, Dt dentary, Exc extracleithrum, icj intracranial joint, ioc infraorbital canal, L.Gu lateral gular, Lj lachrymojugal, mc mandibular canal, L.Ex lateral extrascapular, Op operculum, Par Parietal, Po postorbital, Pop preoperculum, Pp postparietal, Pmx premaxilla, Psym parasymphysial, Q quadrate, Ro.p1 anterior pore of the rostral organ, Ro.p2 antero-lateral pore of the rostral organ, Ro.p3 postero-lateral pore of the rostral organ, So supraorbitals, soc supraorbital canal, Sop Suboperculum, Spl splenial, Sq squamosal.

Systematic palaeontology

Osteichthyes Huxley 1880

Sarcopterygii Romer 1955

Actinistia Cope 1871

Ngamugawi wirngarri gen. et sp. nov.

Diagnosis: Ngamugawi wirngarri gen. et sp. nov. is distinguished from all other coelacanths by the following apomorphies: jugal canal with prominent branches; large sensory pore openings between supraorbitals and parietals; teeth on parasymphysial tooth plate, but not on the dentary; prearticular and/or coronoid teeth rounded; cleithra and extracleithra with broad triangular anteroventral overlap for clavicle bearing a large ventral foramen; and scales with long ornamental ridges extending beyond the posterior margin of the base (Figs. 1, 2, Supplementary Fig. 1).

Locality and horizon: Canning Basin, in northern Western Australia, circa 100 km southeast of Fitzroy Crossing; Gogo Formation, early Frasnian, Late Devonian (~384–382 Ma). The holotype was found between Stromatoporoid Camp and Longs Well, the paratype was found in Paddys Valley. 

Etymology: Generic name meaning “ancient fish” in Gooniyandi/Guniyandi, language of the First Nations people from Country around Fitzroy Crossing in the Kimberley region of Western Australia. Specific name is given in honour of respected Gooniyandi elder and ancestor Wirngarri, who lived in the Emanuel Range. Generic and specific names were both provided to Prof. John Long in September 2023, who has a longstanding and ongoing relationship with the community, with permissions to use the language granted by elder Rosemary Nuggett, on behalf of the Gooniyandi people of the Mimbi community.

Phylogenetic relationships and divergence dates within coelacanths, based on tip-dated Bayesian inference.

A live recreation of the Ngamugawi wirngarri coelacanth in its natural habitat. P3D graphic credit: Katrina Kenny. 

 Illustration by Katrina Kenny (courtesy Flinders University)

 Alice M. Clement, Richard Cloutier, Michael S. Y. Lee, Benedict King, Olivia Vanhaesebroucke, Corey J. A. Bradshaw, Hugo Dutel, Kate Trinajstic and John A. Long. 2024. A Late Devonian coelacanth reconfigures Actinistian Phylogeny, Disparity, and Evolutionary Ddynamics. Nature Communications. 15: 7529. DOI: doi.org/10.1038/s41467-024-51238-4

  

[Paleontology • 2023] Krommaster spinosus • Earliest Known ophiuroids (Ophiuroidea: Encrinasteridae) from high Palaeolatitude, southern Gondwana, recovered from the Pragian to earliest Emsian Baviaanskloof Formation (Table Mountain Group, Cape Supergroup) South Africa

Krommaster spinosus

Reddy, Thuy, Reid & Gess, 2023

 

DOI: 10.1371/journal.pone.0292636

Abstract

For the first time, ophiuroids have been found in South African strata predating the lowermost Bokkeveld Group. These comprise natural moulds and casts from two localities in the ‘upper unit’ of the Baviaanskloof Formation (Table Mountain Group). As a Pragian to earliest Emsian age has been inferred for this member, the new taxa comprise the earliest high-palaeolatitude ophiuroid records from southern Gondwana. Morphological analysis of the specimens revealed the presence of two distinct taxa. One is here described as Krommaster spinosus gen. et sp. nov., a new encrinasterid characterised by very large spines on the dorsal side of the disc, the ventral interradial marginal plates and the arm midlines. The second taxon is a poorly preserved specimen of Hexuraster weitzi, a cheiropterasterid previously described from the slightly younger Bokkeveld Group.

 

   

Krommaster from the Baviaanskloof Formation, Upper Unit, Cape Supergroup, Table Mountain Group, Eastern Cape South Africa paratypes.
 A- part aboral view (AM18224) with disk scales preserved, B- counterpart with holes, which comprise moulds of spines (image reversed) (AM18224A), C- silicone peel of the oral view (AM18221). Abbreviations; PS: periradial suture.

Systematic palaeontology

Class– OPHIUROIDEA Gray, 1840  

Order– OEGOPHIUROIDEA Matsumoto, 1915 

Suborder– LYSOPHIURINA Gregory, 1897  

Family– ENCRINASTERIDAE Schuchert, 1914  

Subfamily– ENCRINASTERINAE Schuchert, 1914  

Krommaster gen. nov.

Diagnosis—Moderately large encrinasterid with disk covered by a mosaic of small, thin scales and extending to the 5th or 6th arm segment; interradii bound by relatively small marginal plates except for a single larger plate bearing a single very large, conical, pointed spine; similar but slightly smaller spines on dorsal disk and along the dorsal midline of the arms; ambulacrals with a very sharp transverse furrow close to the distal edge of the leg of the boot; adambulacral plates with two to three relatively large, short, conical, pointed lateral arm spines.

Etmology—‘Kromm’ From Kromme River, in the canyon of which the ophiuroid lag deposit was recovered. Krom is the Afrikaans word for curve. ‘Aster’, latin meaning star.

Krommaster spinosus sp. nov.

 Etymology—‘spinosus’, latin for spiny or spiky, referring to the presence of large spines on the central disk and arms.

Type locality and stratum—Early Devonian, Pragian to earliest Emsian, ‘upper unit,’ Baviaanskloof Formation, Table Mountain Group, Cape Supergroup, Eastern Cape, South Africa.

  Caitlin Reddy, Ben Thuy, Mhairi Reid and Robert Gess. 2023. Earliest known ophiuroids from high palaeolatitude, southern Gondwana, recovered from the Pragian to earliest Emsian Baviaanskloof Formation (Table Mountain Group, Cape Supergroup) South Africa. PLoS ONE. 18(10): e0292636. DOI: 10.1371/journal.pone.0292636

 phys.org/news/2023-11-oldest-samples-brittle-stars-supercontinent.html

[PaleoIchthyology • 2024] Harajicadectes zhumini • A New Stem-Tetrapod Fish (Sarcopterygii: Tetrapodomorpha) from the Middle–Late Devonian of central Australia

 

 Harajicadectes zhumini

Choo, Holland, Clement, King, Challands, Young & Long, 2024

 DOI: 10.1080/02724634.2023.2285000  

Illustration by Brian Choo

ABSTRACT

Remote Devonian exposures in central Australia have produced significant but highly fragmentary remains of fish-grade tetrapodomorphs. We describe a new tetrapodomorph from the Middle–Late Devonian (Givetian–Frasnian) Harajica Sandstone Member of the Amadeus Basin, Northern Territory, which is represented by several nearly complete skulls along with much of the body and postcranial skeleton. The new form has a posteriorly broad postparietal shield, broad, triangular extratemporal bones, and a lanceolate parasphenoid. The spiracular openings are particularly large, a character also recorded in elpistostegalians and Gogonasus, demonstrating that these structures, suggestive of spiracular surface air-breathing, appeared independently in widely differing nodes of the stem-tetrapod radiation. A phylogenetic analysis resolves the new form within a cluster of osteolepidid-grade taxa, either as part of a polytomy or as the most basally-branching representative of a clade containing ‘osteolepidids,’ canowindrids, and megalichthyids.

  Harajicadectes zhumini from the Harajica Sandstone Member (Givetian–Frasnian), Northern Territory, Australia, Holotype NTM P6410.
A, photographed as a natural mold in situ as it was discovered in 2016; B, as a whitened latex peel; and C, interpretative drawing.

SYSTEMATIC PALEONTOLOGY

OSTEICHTHYES Huxley, 1880

SARCOPTERYGII Romer, 1955

TETRAPODOMORPHA Ahlberg, 1991

Genus HARAJICADECTES gen. nov.

HARAJICADECTES ZHUMINI, gen. nov. et sp. nov.

Diagnosis—Tetrapodomorph fish with greatly enlarged spiracular openings, comprising over 20% of the total length of the skull-roof, bordered by the tabular, extratemporal, and squamosal. Parietal and postparietals of roughly equal length. Elongate intertemporal that widens anteriorly. Posterior nasals narrower than the anterior and posterior supraorbitals. Median extrascapular tapers anteriorly into a V-shaped recess formed by the large rounded lateral extrascapulars. Elongate lanceolate parasphenoid with denticles larger on the anterior part of the bone. Scales display ridged ornamentation and lack cosmine. Anterior squamation cycloid, abruptly shifting to a rhombic shape on the rear flank.

Etymology—“Harajica Biter.” Named for the Harajica Sandstone Member and the ancient Greek dēktēs (“biter”) in reference to the animal’s large fangs and presumed predatory habits. The species honors Professor Min Zhu of the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China, for his numerous contributions to early vertebrate paleontology.

Type Locality and Horizon—Harajica Sandstone Member of the Parke Siltstone. Locality 6 of Young (Citation1985), about 2 km southwest of the southern end of Stokes Pass, Amadeus Basin, Northern Territory. Givetian–Frasnian in age (Fig. 1).

Life reconstruction of  Harajicadectes zhumini, a 40 cm long lobe-finned fish that is not too distantly related to the fishes that gave rise to the earliest limbed tetrapods.

(Illustration by Brian Choo, Flinders University)

 

 

Brian Choo, Timothy Holland, Alice M. Clement, Benedict King, Tom Challands, Gavin Young and John A. Long. 2024. A New Stem-Tetrapod Fish from the Middle–Late Devonian of central Australia. Journal of Vertebrate Paleontology. e2285000. DOI: 10.1080/02724634.2023.2285000  

[Paleontology • 2022] Needmorella simoni • A New Trilobite Genus (Dalmanitidae: Synphoriinae) from the Lower–Middle Devonian of West Virginia

Needmorella simoni 

Holloway & Scott, 2022

DOI: 10.1017/jpa.2022.96 

 twitter.com/scottforteacher 

Abstract 

The trilobite Needmorella new genus, with type species Needmorella simoni new genus new species from the late Emsian to mid-Eifelian Needmore Shale of West Virginia, is a distinctive member of the subfamily Synphoriinae. It also occurs in the same formation in Pennsylvania and Virginia. It is not very similar to other Devonian representatives of the subfamily and is considered to have its origins in a morphologically less-derived ancestor because it shares certain similarities with Silurian genera, including the very short anterior cephalic border unmodified by crenulations or spines, S2 that is not largely reduced to a deep pit adaxially, the relatively low inflation of L3, and the well-defined interpleural furrows on the pygidium. Other particularly distinctive characters of the genus include the very long genal spines and the abaxially inflated and expanded posterior pleural bands on the thorax and pygidium that project slightly distally. The conventional concept of the Devonian synphoriine Anchiopsis Delo, 1935 appears to be incompatible with the holotype of the type species, judging from the early illustrations of the specimen, and the genus could be a synonym of Synphoria Clarke, 1894.

 

David J. Holloway and Brian M. Scott. 2022. Needmorella, A New Trilobite Genus of the Synphoriinae (Dalmanitidae) from the Lower–Middle Devonian of West Virginia. Journal of Paleontology. DOI: 10.1017/jpa.2022.96

  twitter.com/scottforteacher/status/1600246058730524673

[PaleoIchthyology • 2023] Foxaspis novemura • Postcranial Disparity of galeaspids (Galeaspida) and the Evolution of Swimming Speeds in Stem-gnathostomes

Foxaspis novemura

Gai, Lin, Shan, Ferrón & Donoghue, 2023

DOI: 10.1093/nsr/nwad050 

 Researchgate.net/publication/368895582

Abstract

Galeaspids are extinct jawless relatives of living jawed vertebrates whose contribution to understanding the evolutionary assembly of the gnathostome bodyplan has been limited by absence of postcranial remains. Here, we describe Foxaspis novemura gen. et sp. nov., based on complete articulated remains from a newly discovered Konservat-Lagerstätte in the Early Devonian (Pragian, ∼410 Ma) of Guangxi, South China. F. novemura had a broad, circular dorso-ventrally compressed headshield, slender trunk and strongly asymmetrical hypochordal tail fin comprised of nine ray-like scale-covered digitations. This tail morphology contrasts with the symmetrical hypochordal tail fin of Tujiaaspis vividus, evidencing disparity in galeaspid postcranial anatomy. Analysis of swimming speed reveals galeaspids as moderately fast swimmers, capable of achieving greater cruising swimming speeds than their more derived jawless and jawed relatives. Our analyses reject the hypothesis of a driven trend towards increasingly active food acquisition which has been invoked to characterize early vertebrate evolution.

Keywords: Galeaspida, jawed vertebrates, evolution, functional morphology, phylogenetics, modelling

Class Galeaspida Tarlo, 1967

Order Polybranchiaspidiformes Liu, 1965

Family Duyunolepididae P'an et Wang, 1978

Genus Foxaspis gen. nov.

Foxaspis novemura gen. et sp. nov.

 

Etymology. After the nine-tailed fox, a creature spoken of in the ancient Chinese mythological bestiary, the Shan-hai Ching (Classic of Mountains and Seas) which is a compilation of mythic geography and myth. Latin novem meaning nine; Latin -ura, meaning tail.

Holotype. A complete headshield articulated with body and tail V30958.1a,bpreserved together with a complete arthrodiran fish (Fig.1A,B).

Locality and horizon. Tongmu Town, Jinxiu County, Laibin City, Guangxi ZhuangAutonomous Region, China, the Xiaoshan Formation, Pragian, Early Devonian (Supplementary Fig. 1).

Zhikun Gai, Xianghong Lin, Xianren Shan, Humberto G. Ferrón and Philip C. J. Donoghue. 2023. Postcranial Disparity of galeaspids and the Evolution of Swimming Speeds in Stem-gnathostomes. National Science Review. nwad050. DOI: 10.1093/nsr/nwad050

  Researchgate.net/publication/368895582_Postcranial_disparity_of_galeaspids_and_the_evolution_of_swimming_speeds_in_stem-gnathostomes

[PaleoIchthyology • 2023] Maghriboselache mohamezanei • Broad Snouted cladoselachian (Symmoriiformes: Cladoselachidae) with Sensory Specialization at the Base of modern Chondrichthyans

Maghriboselache mohamezanei 

Klug, Coates, Frey, Greif, Jobbins, Pohle, Lagnaoui, Haouz & Ginter, 2023

  

DOI: 10.1186/s13358-023-00266-6

Abstract

Throughout the Silurian and Devonian, cartilaginous fish successively evolved their specialized skeletal and dental characteristics, and increasingly refined their sensory systems. The Late Devonian shark taxon Maghriboselache mohamezanei gen. et sp. n. from the eastern Anti-Atlas of Morocco is known from multiple specimens preserving most of its skeletal features, which in some instances are preserved in three dimensions. Key details of the dentition, jaws, and pectoral skeleton are shared with the iconic genus Cladoselache. Phylogenetic analyses place the family Cladoselachidae as the sister group of symmoriiforms and these groups as sister group of the holocephalans. Further phylogenetic results corroborate that the initial evolutionary radiation of crown chondrichthyans occurred within or before the Late Devonian. Remarkably, this new stem holocephalan is equipped with a wide snout and large laterally separated nasal capsules: the earliest known example of this condition in the chondrichthyan and (perhaps) gnathostome record. This suggests sensory specialization approaching that of extant broad-rostrum elasmobranchs and represents a significant addition to increasingly apparent ecomorphological diversity among early chondrichthyans.

Photo and drawing of a nearly complete skeleton of Maghriboselache mohamezanei n. gen. et sp., AA.BER.DS.01. The marked fin spine belongs to the posterior fin

Skeletal reconstruction of possibly a male (A dorsal. B lateral) and possibly a female (C bottom, lateral) of Maghriboselache mohamezanei n. gen. et sp. The according details were collected from the mentioned specimens. Note the presence of anterior dorsal fin spine in the supposed males, possibly serving a role during copulation. Claspers are not present in the supposed males of our sample. The photos show the according regions of specimens displayed in Fig. 1 and the Additional file 1

Systematic palaeontology

Chondrichthyes (Huxley, 1880).

Holocephali (Bonaparte, 1838).

Symmoriiformes (Zangerl, 1981).

Cladoselachidae (Dean, 1909a).

Diagnosis: Symmoriiform chondrichthyans with pectoral fins with distally broad, flat, strap-like radials. Cleaver-shaped palatoquadrate with otic process shorter than palatine process; jaw articulation barely posterior to occipital level. Teeth with tall median cusp flanked by much smaller lateral cusps and tooth base with a deep basolabial depression flanked by adjacent projections.

Remarks: This family now comprises the genera Cladoselache and Maghriboselache, thus far limited to the Famennian of the USA and Morocco.

Maghriboselache gen. n.

Etymology: From the Arabic word al Maghrib for Morocco and the Greek word σέλαχος (selachos) for cartilaginous fish.

 

Diagnosis: Cladoselachiid distinguished by neurocranium with broad flattened rostrum enclosing large, widely separated, nasal capsules. Rostral span, including the nasal capsules, matches span of the postorbital arcade. Postorbital arcade surrounds small jugular foramen. Ventral extremity of postorbital arcade extends anteriorly, contributing to orbit floor and almost meeting posterolateral extremity of rostral cartilage and postnasal wall. Otic process of palatoquadrate anteroposteriorly short, in lateral view terminating level with, or just caudal to, the posterior extremity of the occipital cartilage. Dentition with enlarged teeth on the mandibular symphysis. Scapulocoracoid with ventrally broad scapula process and sturdy coracoid region with slender, distinct, procoracoid cartilage. Anterior dorsal fin spine (if present): long, laterally flattened and smooth, curved posteriorly throughout length.

Maghriboselache mohamezanei sp. n.

 

Holotype: AA.MEM.DS.12, which preserves the 3D neurocranium, teeth, shoulder girdle, and most fins, and hence most of the relevant body parts.

 

Age: Thylacocephalan Layer, late early to early middle Famennian, Late Devonian.

Type locality: Mousgar, southern Maïder, southeastern Anti-Atlas, Morocco.

Etymology: Referring to Moha Mezane (El Khraouia & Merzouga, Morocco), French linguist and amateur geologist, specialized in fossils and minerals from the southern Tafilalt. He found many important specimens including some of the material described here.

Reconstruction of Maghriboselache mohamezanei n. gen. et sp. in its habitat. Thylacocephalans, cephalopods with orthoconic conchs, placoderms such as Dunkleosteus and osteichthyans populated the water column during the middle Famennian in the Anti-Atlas

Christian Klug, Michael Coates, Linda Frey, Merle Greif, Melina Jobbins, Alexander Pohle, Abdelouahed Lagnaoui, Wahiba Bel Haouz and Michal Ginter. 2023. Broad Snouted cladoselachian with Sensory Specialization at the Base of modern Chondrichthyans. Swiss Journal of Palaeontology.  142:2. DOI: 10.1186/s13358-023-00266-6

[PaleoIchthyology • 2023] Hyneria udlezinye • A high Latitude Gondwanan Species of the Late Devonian tristichopterid Hyneria (Osteichthyes: Sarcopterygii) from South Africa

 

 Hyneria udlezinye

Gess & Ahlberg, 2023

DOI: 10.1371/journal.pone.0281333

Painting by Maggie Newman

Abstract

We describe the largest bony fish in the Late Devonian (late Famennian) fossil assemblage from Waterloo Farm near Makhanda/Grahamstown, South Africa. It is a giant member of the extinct clade Tristichopteridae (Sarcopterygii: Tetrapodomorpha) and most closely resembles Hyneria lindae from the late Famennian Catskill Formation of Pennsylvania, USA. Notwithstanding the overall similarity, it can be distinguished from H. lindae on a number of morphological points and is accordingly described as a new species, Hyneria udlezinye sp. nov. The preserved material comprises most of the dermal skull, lower jaw, gill cover and shoulder girdle. The cranial endoskeleton appears to have been unossified and is not preserved, apart from a fragment of the hyoid arch adhering to a subopercular, but the postcranial endoskeleton is represented by an ulnare, some semi-articulated neural spines, and the basal plate of a median fin. The discovery of H. udlezinye shows that Hyneria is a cosmopolitan genus extending into the high latitudes of Gondwana, not a Euramerican endemic. It supports the contention that the derived clade of giant tristichopterids, which alongside Hyneria includes such genera as Eusthenodon, Edenopteron and Mandageria, originated in Gondwana.

Systematic palaeontology

OSTEICHTHYES Huxley, 1880

SARCOPTERYGII Romer, 1955

TETRAPODOMORPHA Ahlberg, 1989

TRISTICHOPTERIDAE Cope, 1889

Diagnosis— Tetrapodomorph sarcopterygians with postspiracular bone present, vomers with long caudal process clasping the parasphenoid, circular scales with a median boss, and an elongate body with a trifurcate or rhombic caudal fin (modified from [3]).

HYNERIA Thomson, 1968

Type species— Hyneria lindae Thomson, 1968; Hyner, Pennsylvania, USA.

AM6540b and AM6528a, the two main blocks of the holotype of Hyneria udlezinye.
Each block also has a counterpart (not illustrated). A, AM6540b. Unlabelled bones all belong to a single large individual of the arthrodire placoderm Groenlandaspis riniensis [Long, et al. 1997]. B, AM6528a. This block also carries a jugal of the tetrapod Umzantsia amazana [Gess & Ahlberg, 2018] and a paranuchal of a small individual of Groenlandaspis riniensis.

Skull reconstruction of Hyneria udlezinye.
Dorsal (A) and lateral (B) views, drawn from photographs of a three-dimensional model, scaled to the size of the holotype.

Abbreviations: An, anocleithrum; Ang, angular; Cl, clavicle; Cle, cleithrum; De, dentary; It, intertemporal; Ju, jugal; La, lacrimal; M.Pr, median postrostral; Mx, maxilla; Op, opercular; Pa, parietal; Pi, pineal; Po, postorbital; Pop, preopercular; Pospl, postsplenial; Pp-St-Ta, postparietal, supratemporal and tabular (sutures not visible); Qj, qudratojugal; Sop, subopercular; Sq, squamosal; Sur, surangular.

Hyneria udlezinye sp. nov.  

"Probable eusthenopterid" [Gess & Hiller, 1995]

"Close to Eusthenodon" [Anderson, et al., 1999]

"Similar to Hyneria" [Gess & Coates, 2008]

"cf Hyneria" [Gess, 2011]

"Hyneria-like" [Gess & Whitfield, 2020]

Diagnosis—A very large tristichopterid, closely resembling Hyneria lindae but differing from it in the following respects: postparietal shield widening more strongly from anterior to posterior; lateral corner of tabular weakly developed; preopercular and lacrimal proportionally deeper; denticulated field on parasphenoid extends further anteriorly; subopercular more shallow; dentary fangs proportionately larger.

Etymology— an apposition, from isiXhosa ‘udlezinye’, meaning ‘one who eats others’, referring to the inferred predatory lifestyle of the species. IsiXhosa is the widely spoken indigenous language of south-eastern South Africa where the fossil locality is located.

Life reconstruction of the non-marine component of the Waterloo Farm biota. Hyneria udlezinye is shown together with the tetrapods Umzantsia amazana and Tutusius umlambo [Gess & Ahlberg, 2018], the placoderms Groenlandaspis riniensis and Bothriolepis africana [Long, et al., 1997], the coelacanth Serenichthys kowiensis [Gess & Coates, 2015], the lungfish Isityumzi mlomomde [Gess & Clemen, 2019], and a cyrtoctenid eurypterid.

Painting by Maggie Newman, copyright R. W. Gess.

Conclusion: 

The largest osteichthyan member of the Waterloo Farm vertebrate assemblage, a predatory sarcopterygian with a probable maximum length of nearly three metres, proves to be a new species of the genus Hyneria. This genus is otherwise only recorded from the late Famennian Catskill Formation of Pennsylvania. The new species, Hyneria udlezinye, differs from the type species Hyneria lindae in a number of minor but securely attested proportional characters relating to the skull roof, cheek, lower jaw and operculum. Hyneria now joins Eusthenodon and Langlieria as one of the derived, late, giant tristichopterids known from both Euramerica and Gondwana. The other confirmed members of this clade (Mandageria, Cabonnichthys and Edenopteron) are exclusively known from Gondwana. This strongly supports the contention that this clade represents a Gondwanan radiation [Olive, et al. 2020].

Hyneria udlezinye is the first tristichopterid to be recorded from a high palaeolatitude, all other members of the group coming from palaeoequatorial to mid-palaeolatitude localities. All previously recorded Gondwanan members of the derived tristichopterid clade come from Australia, leading Olive et al. [2020] to argue for an Australian origin for this clade. The new evidence from Waterloo Farm, however, suggests that a more general Gondwanan origin for this clade is highly likely. This once again demonstrates how inferences about biogeographical patterns have historically been skewed by a paucity of data from high-palaeolatitude localities. Such data can only come from Gondwana, as no continents extended into northern high latitudes during the Devonian. The Waterloo Farm lagerstätte provides a unique window into an almost unknown part of the Late Devonian world.

Robert W. Gess and Per E. Ahlberg. 2023. A high Latitude Gondwanan Species of the Late Devonian tristichopterid Hyneria (Osteichthyes: Sarcopterygii). PLoS ONE. 18(2): e0281333. DOI: 10.1371/journal.pone.0281333

[Paleontology • 2023] Cribroconcha honggulelengensis • Allometry in Late Devonian Podocopa Ostracods (Crustacea) and its implications for Ostracod Ontogeny

Cribroconcha honggulelengensis Song & Crasquin, 2017

in the Upper Devonian Hongguleleng Formation 

of western Junggar, NW China

in Song, Huang & Qie, 2023. 

DOI: 10.1002/spp2.1480

NIGPAS.cas.cn

 Abstract

Podocopa ostracods have abounded in various marine and non-marine habitats since the early Palaeozoic and left a diverse fossil record in strata worldwide. This is particularly useful for stratigraphic correlation and palaeoenvironmental and palaeogeographical reconstructions. However, despite being the most numerous ostracods during the Palaeozoic, their origins, evolution, ontogeny and phylogeny remain poorly defined. This paper represents the first study of morphological variation in Devonian Platycopida ostracods (an order of Podocopa) using a geometric morphometric approach. Our results identify substantial shape variation in Cribroconcha honggulelengensis Song & Crasquin from the Upper Devonian Hongguleleng Formation of western Junggar, northwest China, demonstrating a remarkable change in juveniles between stages A-3 and A-2. Using linear regressions between principal component scores from right lateral view and carapace length, we demonstrate allometric growth patterns for this species. The body plan of C. honggulelengensis developed along an ontological variable: from an ovate outline with rare pores to an oblong outline with dense and large pores. Environmental factors should play an important role in shape determination during ontogeny of C. honggulelengensis.

Ecological reconstruction and life mode interpretation of Cribroconcha honggulelengensis Song & Crasquin, 2017 in the Upper Devonian Hongguleleng Formation of western Junggar, NW China

  

Junjun Song, Bing Huang and Wenkun Qie. 2023. Allometry in Late Devonian Podocopa Ostracods (Crustacea) and its implications for Ostracod Ontogeny. Papers in Palaeontology. DOI: 10.1002/spp2.1480

Study on ontogeny of Platycopida ostracods in Late Devonian reveals the mystery of Paleozoic ostracod evolution

http://english.NIGPAS.cas.cn/new/hs/rp/202302/t20230214_327067.html

https://phys.org/news/2023-02-reveals-mystery-paleozoic-ostracod-evolution.html