[Most Recent Entries] [Calendar View]
Thursday, March 21st, 2024
| Time | Event | ||||||||
| 6:51a | [PaleoMammalogy • 2024] Pebanista yacuruna • The Largest Freshwater Odontocete (Odontoceti: Platanistidae) : A South Asian River Dolphin relative from the proto-Amazonia
Abstract Several dolphin lineages have independently invaded freshwater systems. Among these, the evolution of the South Asian river dolphin Platanista and its relatives (Platanistidae) remains virtually unknown as fossils are scarce. Here, we describe Pebanista yacuruna gen. et sp. nov., a dolphin from the Miocene proto-Amazonia of Peru, recovered in phylogenies as the closest relative of Platanista. Morphological characters such as an elongated rostrum and large supraorbital crests, along with ecological interpretations, indicate that this odontocete was fully adapted to fresh waters. Pebanista constitutes the largest freshwater odontocete known, with an estimated body length of 3 meters, highlighting the ample resource availability and biotic diversity in the region, during the Early to Middle Miocene. The finding of Pebanista in proto-Amazonian layers attests that platanistids ventured into freshwater ecosystems not only in South Asia but also in South America, before the modern Amazon River dolphin, during a crucial moment for the Amazonian evolution.
 
   Systematic paleontology Odontoceti Platanistidae Pebanista yacuruna sp. nov. Etymology: The generic name Pebanista stresses the relationship between this taxon from the Pebas Fm. (section S1) and the extant Ganges and Indus river dolphins Platanista (Platanista gangetica and Platanista minor). The specific Kichua (northern Quechua) name honors the “yacuruna,” a mythical water creature in the Peruvian Amazonia. Diagnosis and remarks: The holotype skull of Pebanista yacuruna, MUSM 4017, has a preserved condylobasal length of 698 mm and an estimated bizygomatic width of 281 mm. The sutures between the cranial bones (e.g., maxilla-premaxilla suture along the rostrum) are well closed or fused, indicating an adult stage. Pebanista is recognized as a member of Platanistidae by having the vertex of the skull deviated leftwards (Fig. 2, A and B); asymmetry of the premaxillae in the rostrum and facial areas of the skull; braincase anteroposteriorly shorter than wide; and lack of contact of the palatines, with both projecting dorsolaterally (figs. S3 and S4). The rostrum of the holotype specimen is dorsoventrally flattened and elongated, a condition shared with the extinct Pomatodelphis, Prepomatodelphis, and Zarhachis, in contrast to the transversely compressed rostrum of extant Platanista. On the preserved portion, the rostrum is formed by the premaxillae, maxillae, and ... 
Aldo Benites-Palomino, Gabriel Aguirre-Fernández, Patrice Baby, Diana Ochoa, Ali Altamirano, John J. Flynn, Marcelo R. Sánchez-Villagra, Julia V. Tejada, Christian de Muizon and Rodolfo Salas-Gismondi. 2024. The Largest Freshwater Odontocete: A South Asian River Dolphin relative from the proto-Amazonia. SCIENCE ADVANCES. 10(12); DOI: 10.1126/sciadv.adk6320  | ||||||||
| 9:28a | [PaleoIchthyology • 2024] Rostral and Body Shape Analyses reveal Cryptic Diversity of Late Jurassic batomorphs (Chondrichthyes: Elasmobranchii) from Europe
Abstract The fossil record of chondrichthyans (chimaeras, sharks, rays and skates) consists largely of isolated teeth, with holomorphic specimens being extraordinary exceptions. However, numerous of these more or less completely preserved specimens are known from several Upper Jurassic deposits of Europe, enabling detailed analysis of their morphology. Batomorphs (rays and skates) resembling modern guitarfishes and wedgefishes (Rhinopristiformes) are among the most common Jurassic chondrichthyans found, but they have been only sporadically studied up to now, resulting in large knowledge gaps concerning their taxonomy and phylogeny. Here, we present the most detailed revision of Late Jurassic holomorphic batomorphs to date, quantitatively analysing body proportions of specimens from Germany (Solnhofen Archipelago), France (Cerin) and the UK (Kimmeridge), using both geometric and traditional morphometrics. Furthermore, we identify qualitative morphological characters for species discrimination, to clarify the taxonomic identity and diversity of Late Jurassic batomorphs based on holomorphic specimens. Our results support the validity of Belemnobatis sismondae, Kimmerobatis etchesi and Spathobatis bugesiacus, as well as that of the previously doubtful Asterodermus platypterus. Moreover, we describe Aellopobatis bavarica, a new taxon, which has hitherto been considered to be a large-sized morphotype of Spathobatis bugesiacus. Our results highlight that the diversity of holomorphic batomorphs during the Late Jurassic was greater than previously thought, and suggest that this group was already well-established and diverse by this time. This study thus provides vital information about the evolutionary history of Late Jurassic batomorphs and has direct implications for batomorph species that are based on isolated teeth only. Keywords: geometric morphometrics, Batomorphii, Spathobatidae, body shape, cryptic species, Aellopobatis bavarica Class CHONDRICHTHYES Huxley, 1880 Subclass ELASMOBRANCHII Bonaparte, 1838 Cohort EUSELACHII Hay, 1902 Subcohort NEOSELACHII Compagno, 1977 Superorder BATOMORPHII Cappetta, 1980 Order Uncertain Family SPATHOBATIDAE Dames, 1888
Genus Aellopobatis nov. Derivation of name: Münster (1836) described a fossil consisting of a dorsal and a caudal fin, which may well be the first mention of this genus, albeit it is impossible to confirm due to the lack of diagnostic characters; he named it Aellopos after the harpy Aello, a hybrid in Greek mythology with the body of a bird and the head of a woman. To honour this original but preoccupied name, we complement it to Aellopobatis. The Greek Ἀελλώ (Aëllṓ) means ‘storm wind’, and βατίς (batís) means ‘ray’ or ‘skate’; feminine. Stratigraphic & geographic distribution: Upper Jurassic of Europe. Lower Tithonian of the Solnhofen Archipelago (Solnhofen, Eichstätt, Zandt, Kelheim, Langenaltheim, Blumenberg), Bavaria, Germany. Aellopobatis bavarica sp. nov. Derivation of name: The species name bavarica is Latin and means ‘Bavarian’; feminine. Diagnosis: Guitarfish-like batomorph that is unique in the combination of the following characters: exceptionally long rostrum with paddle-shaped rostral appendix; antorbital cartilages present but not extending halfway between the nasal capsules and the propterygium; 38–46 pectoral radials (9–11 propterygial, 9–12 mesopterygial and 20–23 metapterygial); no pectoral radials articulating directly with the scapulocoracoid between the meso- and metapterygium; pectoral radials segmented in up to five segments; at least 14 pairs of ribs; c. 21 basipterygial radials (including one compound radial); puboischiadic bar curved anteriorly; claspers long and slender; no fin spines present. Type locality: Lower Tithonian; Kelheim, Bavaria, Germany. Julia Türtscher, Patrick L. Jambura, Eduardo Villalobos-Segura, Faviel A. López-Romero, Charlie J. Underwood, Detlev Thies, Bruce Lauer, René Lauer and Jürgen Kriwet. 2024. Rostral and Body Shape Analyses reveal Cryptic Diversity of Late Jurassic batomorphs (Chondrichthyes, Elasmobranchii) from Europe. Papers in Palaeontology. DOI: 10.1002/spp2.1552 twitter.com/stem_univie/status/177073286 | ||||||||
| 10:37a | [Botany • 2024] Solenangis impraedicta (Orchidaceae) • A New orchid Species expands Darwin’s predicted pollination guild in Madagascar
Summary The world-renowned pollination system of the long-spurred orchid Angraecum sesquipedale Thouars and the long-tongued hawkmoth Xanthopan praedicta (Rothschild & Jordan, 1903), from Madagascar, is the best-known example of the predictive power of evolutionary ecology, yet its actual degree of specialisation remains poorly described due to the incompleteness of the pollination record of X. praedicta. Here, we describe another species from Madagascar, an angraecoid orchid distantly related to the genus Angraecum Bory, that has evolved these extreme adaptations to a single pollinator after a pollinator shift. It bears the longest spur of any flowering plant, relative to flower diameter, reaching 33 cm. The discovery of a species with such an exceptionally long spur is a rare event, the most recent dating to 19653. This novelty is described here as Solenangis impraedicta (Figure 1A–F) and discussed in a phylogenetic framework. Its conservation status is assessed as Endangered.     Solenangis impraedicta Stévart, Farminhão, Savignac, Verlynde & Ramand., sp. nov.   João Farminhão, Marie Savignac, Vincent Droissart, Porter P. Lowry II, Nirina Rajaonarivelo, Brigitte Ramandimbisoa, Simon Verlynde, Arsela Todivelo and Tariq Stévart. 2024. A New orchid Species expands Darwin’s predicted pollination guild in Madagascar. Current Biology. 34(5); R189-R190. DOI: 10.1016/j.cub.2024.01.012 International team discovers new species of orchid from Madagascar pages.uc.pt/en/uc-news/articles/interna www.nybg.org/planttalk/international-te |
| << Previous Day |
2024/03/21 [Calendar] |
Next Day >> |