Oxydoras sp.
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publication ID |
https://doi.org/ 10.5252/geodiversitas2023v45a10 |
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publication LSID |
urn:lsid:zoobank.org:pub:D9FCBF4D-8B95-47E1-B116-98A4BB75352A |
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DOI |
https://doi.org/10.5281/zenodo.8057122 |
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persistent identifier |
https://treatment.plazi.org/id/4812EA70-5776-8A2F-FBE7-355211EAE5EC |
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treatment provided by |
Felipe |
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scientific name |
Oxydoras sp. |
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( Fig. 3 View FIG C1-C3).
MATERIAL EXAMINED. — Incomplete neurocranium ( ULA-1316 ) .
LOCALITY. — Villavieja Fm. LA-3 (fish bed) (seeFig.1B; Appendix 1).
DESCRIPTION
ULA-1316 is an incomplete neurocranium of 51 mm in length, preserving only the anterior section of the skull ( Fig. 3 View FIG C1-C3), and is assigned here to Oxydoras . It preserves a complete mesethmoid bone clearly observable in both dorsal and ventral views. It has an elongate arrow-shape with a bifid anterior tip, and a convex profile in lateral view ( Fig. 3 View FIG C1). In dorsal view, the anterior section of both right and left frontals and both right and left lateral ethmoids are articulated to the mesethmoid; the most proximal section of the anterior cranial fontanelle is also preserved ( Fig. 3 View FIG C1). The ornamentation of the skull is not well defined, possibly as a result of erosion. In ventral view, the mesethmoid, vomer, remnants of what appear to be lateral ethmoids, and the parasphenoid are preserved ( Fig. 3 View FIG C2). The vomer has an arrow-shaped anterior section and seems to have reduced anterolateral processes; its posterior section is elongated and narrow, being enclosed in the anterior bifid tip of the parasphenoid.
REMARKS
ULA-1316 possess a mesethmoid bone similar to those present in living and fossil representatives of Oxydoras , which can be differentiated from the mesethmoid bones of any other living ( Birindelli 2014) or fossil (see Lundberg et al. 2010) species of doradid. The thorny catfish Oxydoras is represented by three extant species, Oxydoras niger (Valenciennes in Humboldt & Valenciennes, 1821), Oxydoras kneri Bleeker, 1862a , and Oxydoras sifontesi Fernández-Yépez, 1968 , from the Amazon, Essequibo, Orinoco and Paraná basins. These species occur over mud in streams and lakes, but are also present in large rivers ( Froese & Pauly 2022). The only fossil of Oxydoras known to date corresponds to an isolated mesethmoid bone from the Miocene of Peru illustrated by Lundberg et al. (2010). Although ULA-1316 resembles the skull of the extant O. niger (see Birindelli 2014; Prestes-Carneiro et al. 2019), and/ or the other two living species O. kneri and O. sifontesi , its incomplete and poor state of preservation make it difficult to associate this fossil specimen with any of these extant species. The skulls of the extant species of Oxydoras usually present well-defined ornamentation (see Birindelli 2014: fig. 25); in the case of ULA-1316, the ornamentation pattern is not well-defined or is absent, possibly as a consequence associated with taphonomic processes or erosion of the fossil during its exposure in the outcrop. Due to that, ULA-1316 is tentatively assigned to Oxydoras sp. This fossil specimen from the middle Miocene of the Honda Group, and the isolated mesethmoid bone from the Miocene ( Lundberg et al. 2010), are to date the only known fossils of Oxydoras .
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.