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Language Spanish journal of palaeontology. 2023. Vol. 38, no. 1
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- First record of palaeozoic vertebrates from Peru(2023) Zevallos-Valdivia, Leonardo; Martínez-Pérez, Carlos ; García-Flores, Vilma; Chávez-Valencia, Antenor; Botella, HéctorDevonian vertebrates in South America are notably scarce compared with other continents, becoming this circumstance particularly evident in Peru, where no Palaeozoic vertebrates have been formally reported so far. In this paper, we report, figure and describe the first Devonian vertebrates remains from Peru recovered in the Puno region, south-eastern of the country. The remains belong to the very unusual group of Emsian to Eifelian stem-chondrichthyan Pucapampella and Zamponiopteron that characterise the vertebrate fauna of the so-called marine “Malvinokaffric Realm”. The remains studied are represented by three jaw fragments assigned to Pucapampella, and three fin plates of Zamponiopteron. These records increase the palaeogeographic distribution of this assemblage in the Palaeozoic of Gondwana, but more relevant, our findings highlight the potential of the Peruvian outcrops to contribute to the knowledge on the diversity and distribution of the early vertebrate faunas in the South American continent.
- Thelodont scales from the Lower Devonian of Novaya Zemlya Archipelago, Arctic Russia.(2023) Blom, Henning; Vaškaninová, Valéria; Karatajūtė-Talimaa, Valentina; Žigaitė, ŽivilėScales of a new thelodont species, Amaltheolepis terranovi sp. nov., are described from the upper Emsian, Lower Devonian Shevchenkinskaya Formation of Novaya Zemlya, Arctic Russia. The new species shows strong resemblance with the Emsian “Verdalen assemblage” from Spitsbergen, supporting an Emsian age for the upper part of the Shevchenkinskaya Formation. This conclusion in the context of the various Amaltheolepisassemblages from Spitsbergen allows for a more accurate comparison and correlation between assemblages from different regions in the Northern Hemisphere, suggesting that the type species, Amaltheolepis winsnesifrom Spitsbergen, is Eifelian in age
- An enigmatic chondrichthyan spine from the Visean of Indiana, USA that resembles a median rostral cartilage of Squaloraja (Holocephali, Chimaeriformes)(2023) Itano, Wayne M.; Duffin, Christopher J.Squaloraja is a genus of chimaeriform fishes known from the Early Jurassic. It has a dorsoventrally flattened body and a long median rostral cartilage. Males have a lance-like tenaculum that articulates with a central groove on the dorsal face of the median rostral cartilage. The genus is the only member of the family Squalorajidae, itself the only family in the suborder Squalorajoidei of the order Chimaeriformes. Phylogenetic analyses suggest a divergence of the Squalorajoidei from other Chimaeriformes in the Mississippian, implying the existence of a ghost lineage of more than 130 My. A spine that resembles a median rostral cartilage of a male Squaloraja was found in the St. Louis Formation (Visean) of Indiana, USA. As in Squaloraja, the dorsal face has a long narrow groove that would have articulated with a long narrow tenaculum. The spine is designated as the holotype of Sulcacanthus schachti, n. gen. et sp. Sulcacanthus is tentatively assigned to the Squalorajoidei based on morphology, but the possibility of convergence cannot be eliminated. A holocephalan tenaculum from the same locality might belong to the same taxon as the median rostral cartilage but could also belong to the suborder Myriacanthoidei.
- Teeth and tooth whorls of the stem chondrichthyan Doliodus from the Early Devonian of the Gaspé Sandstone Group, Gaspé Peninsula, Quebec, Canada(2023) Burrow, Carole J.; Desbiens, SylvainThe Early Devonian (Emsian) vertebrate fauna of the Gaspé Peninsula, Quebec (Canada) shows close affinity with the Emsian fauna from the Atholville beds, New Brunswick (Canada). Specimens collected in the early 2000s from several localities in central Gaspé include molds of tooth whorls and isolated teeth that we assign to the stem chondrichthyan Doliodus. Isolated teeth of this taxon were first described from the Atholville beds in the late 1800s by Arthur Smith Woodward, who erected a new species Diplodus problematicus. Whereas the Atholville beds teeth are usually preserved individually or in tooth families, and as hard tissue, the Gaspé teeth are mostly preserved as molds of tooth whorls, with individual teeth sharing a thin bone base. Thin sections of Doliodus teeth from the Atholville beds show parallel close-set vascular canals extending above the base plate and through tooth bases, with teeth formed of osteodentine and meso- or orthodentine. We consider that all the known dental elements assigned to Doliodus are conspecific with the articulated Doliodus specimen and thus all are assigned to the same species D. latispinosus. The teeth are compared with the diplodont teeth of other stem chondrichthyan taxa, in particular the Omalodontiformes.
- Our honoured colleagues, Drs Tiiu Märss and Philippe Janvier, commemorated at the 16th ISELV, Valencia, Spain: personal memories(2023) Turner, SusanThe 16th International Symposium on Early and Lower Vertebrates, Valencia, held in July 2022 was dedicated to the work of two important members of the Palaeozoic fossil fish community who have between them worked on numerous and various vertebrate groups and taxa, notably agnathan and gnathostome fishes. Geologists, Professors Tiiu Märss and Philippe Janvier have collected, studied, illustrated and contributed many books and papers to the science, for which we thank them.
- Non-tetrapod sarcopterygians from the Valentia Slate Formation (Givetian, Devonian) of the Iveragh Peninsula, south-western Ireland: systematic reappraisal and palaeobiogeographic implications(2023) Dupret, Vincent; Byrne, Hannah; Challands, Tom; Hammer, Øyvind; Higgs, Kenneth; Long, John; Niedźwiedzki, Grzegorz; Qvarnström, Martin; Stössel, Iwan; Ahlberg, Per ErikThe Middle Devonian (Givetian) Valentia Slate Formation in the Iveragh Peninsula, southwest Ireland, is more renowned for the second oldest record of tetrapod trackways in the world than for its heavily metamorphosed bone remains. The present study focuses on new discoveries of non-tetrapod sarcopterygian fish fossils from the Valentia Slate Formation. Micro-CT scanning technology allows a re-interpretation of a previously published acanthodian fin spine as a fanged coronoid of a probable Rhizodontida and the identification of a Dipnoi tooth plate and bone. In addition, a scale of Holoptychius is described. The presence the rhizodont suggests Gondwanan ties and a first northward dispersal wave of these vertebrates into Euramerica as early as middle Givetian. This hypothesis is supported by the common occurrence of the placoderm Bothriolepis in the Valentia Slate Formation.
- The dentition of Omalodontiformes, the order of unusual Devonian stem-chondrichthyans(2023) Ginter, MichałThe early chondrichthyan order Omalodontiformes from the late Early Devonian through to the Late Devonian is characterised by specific teeth. Unlike in most Devonian sharks, their bases are directed labially or are reduced and devoid of labial or lingual extensions. In this paper the complex history of investigation on the dermal skeleton of omalodontiforms is presented and the validity of the established taxa is revised. The dentition of an Emsian representative of this group, known from a single articulated specimen (NMBG 10127) and several isolated fin spines from Canada and previously, probably incorrectly, attributed to Doliodus, is distinctly heterodont. The nature of this heterodonty suggests that the two omalodontiform tooth-based genera described originally from the Middle/Upper Devonian Aztec Siltstone (Antarctica), viz. Portalodus and Anareodus, are in fact congeneric as their teeth represent different parts of the same jaw. Because the teeth of the Canadian specimen differ in important aspects from those of typical Doliodus and are generally similar to those of Portalodus, it probably should be placed in a new genus. Also, the validity of the distinction between Portalodus bradshawae and P. mannoliniae is considered questionable.
- Dermal skeleton of the stem osteichthyan Ligulalepis from the Lower Devonian of New South Wales (Australia)(2023) Burrow, Carole J.; Young, Gavin C.; Lu, JingWhen first described based on isolated scales, Ligulalepis was assigned to thePalaeoniscoidea, a basal group of actinopterygians (ray-finned fishes). Recent cladisticanalyses, mainly based on skull and neurocranial characters, have mostly recovered thetaxon (or, ‘Ligulalepis’) as a stem osteichthyan. Here we present information on Ligulalepisdermal elements other than scales and skulls, that include a cheek fragment, a premaxilla,other marginal jaw elements and teeth, an accessory vomer, a partial shoulder girdle,incomplete spine-like elements, and a gular plate. The shoulder girdle and premaxilla compareclosely with those of basal actinopterygians, whereas the spine-like element showssome similarity to the distal end of the spines on medial dorsal plates of the Chinese LateSilurian stem osteichthyans Guiyu and Sparalepis, or alternatively to fin rays on the stemosteichthyan Dialipina. One of the jaw elements appears to be a compound jugal plate pluspart of the dentate maxilla, an arrangement not previously known in any Devonian stemosteichthyan, or actinopterygian. Histological structure of dermal plates somewhat resemblesthat of Meemannia, but pore openings in Ligulalepis lead only to the vascular canalnetwork at the base of the ornament layer and not to a pore canal network. Like previousphylogenetic analyses, our analysis incorporating post-cranial dermal skeleton charactersalso recovered Ligulalepis as a stem osteichthyan.
- A new dipnoan species Janvierpaucidentes tuulingi gen. et sp. nov. from the Pragian (Early Devonian) of Mimerdalen, Svalbard (Norway), with an unusual dentition(2023) Johanson, Zerina; Newman, Michael; Rangel-De Lazaro, Gizeh; Smith, Moya M.; Jones, RogerA new dipnoan lower jaw from the Wood Bay Formation (Pragian) of Svalbard (Norway), preserves a partial dentary and partial toothplates referred to the new species Janvierpaucidentes tuulingi gen. et sp. nov. The more complete toothplate is elongate with three short rows of teeth but is damaged medially. A large number of dipnoans are known from the early Devonian, showing a range of dentitions. Other tooth-plated dipnoans from this time period include Diabolepis speratus, Speonesydrion iani, Tarachomylax oepiki, Tarachomylax multicostatus, Ichnomylax kurnae and Ichnomylax karatajae, and two unnamed toothplates from Vietnam. In Melanognathus canadensis, rows of teeth are located along the prearticular, which is otherwise covered in a shagreen of denticles; this denticle-dominated dentition also characterized Uranolophus wyomingensis. The dentition of Janvierpaucidentes tuulingi differs from these toothplate morphologies and is highly unusual in having the more rostral and caudal tooth rows nearly paralleling the jaw margin, with a maximum angle between the tooth rows approaching 180 degrees. In this character, Janvierpaucidentes tuulingi is more comparable to taxa such as Xylognathus macrustenus from the Carboniferous, increasing the already high disparity of lungfish dental morphology in the Devonian.
- "Carbonífero de Puertollano" Natural Monument (Puertollano basin, Spain): a window for the knowledge of Early Vertebrates(2023) Soler-Gijón, Rodrigo; Díez Ruiz, AntonioCoal mining at the Puertollano Carboniferous basin has led to the discovery and study of numerous fossiliferous layers, rich in chondrichthyan, actinopterigyan and tetrapod remains. The end of the mining operations and closure of the mines could also represent complete cease of paleontological prospections and field work at the Puertollano basin. Fortunately, three quarries, called María Isabel, La Extranjera and La Tejera, have been declared a Natural Monument. Consequently, they are protected by law and reserved for geological and palaeontological scientific research. In this paper, we describe the geology of the Natural Monument and its vertebrate fossil record. The outcrops of the three quarries show the most superficial part of the stratigraphic series so that they inform about the latest stages of the sedimentological and palaeogeographical evolution of the Puertollano basin. The actual coal basin appears to represent a remnant of a much larger basin which opened eastward to the Paleo-Tethys. The diverse chondrichthyan assemblage (acanthodians, xenacanths and euselachians) and euryhaline actinopterygians, and the presence of tidal rhythmites, indicate an estuarine-deltaic environment. Future sedimentological and paleontological studies at the Natural Monument will inform about the degree of marine influence in the basin and the changes of the vertebrate communities.
