Asterolepis alticristata Downs & Daeschler & Lo & Carey & Shubin 2019, n. sp.
Asterolepis alticristata n. sp. Asterolepis sp. – Daeschler et al. 2006: 759. “Large asterolepidid” – Downs et al. 2011a: 994. “Asterolepid placoderm” – Downs et al. 2013: 48. “Asterolepid antiarch” – Downs et al. 2018: 1. HOLOTYPE. — NUFV 897, anterior median dorsal plate of thoracic skeleton (Fig....
| Main Authors: | , , , , |
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| Format: | Other/Unknown Material |
| Language: | unknown |
| Published: |
2019
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| Subjects: | |
| Online Access: | https://zenodo.org/record/3703489 https://doi.org/10.5281/zenodo.3703489 |
| Summary: | Asterolepis alticristata n. sp. Asterolepis sp. – Daeschler et al. 2006: 759. “Large asterolepidid” – Downs et al. 2011a: 994. “Asterolepid placoderm” – Downs et al. 2013: 48. “Asterolepid antiarch” – Downs et al. 2018: 1. HOLOTYPE. — NUFV 897, anterior median dorsal plate of thoracic skeleton (Fig. 2). ETYMOLOGY. — From the Latin ‘altus,’ high, and ‘crista,’ crest, in reference to the tall midline crest of the anterior median dorsal plate that helps to diagnose the species. TYPE LOCALITY AND HORIZON. — NV 2K17 locality (77˚09’59.1”N, 86˚16’9.42”W), Fram Formation near the eastern arm of Bird Fiord on southern Ellesmere Island, Nunavut Territory, Canada. Palynological data indicate an early Frasnian age (medius and maclarenii zones of Chi & Hills 1976). REFERRED MATERIAL. — NUFV 1265, nuchal plate; NUFV 812, 813, premedian plates; NUFV 822, partial anterior median dorsal plate; NUFV 814, 815, 823, 828, 834, 835, 842, 845, 849-851, 854, 856, 860-861, 864, 867, 870-873, 876-878, 884-886, 889, 890, 896, 1270-1277, crests of anterior median dorsal plates; NUFV 796, 806, 874, 879, 898, posterior median dorsal plates; NUFV 802.1, 802.2, 821, 848, posterior median dorsal fragments; NUFV 892, articulated partial thoracic and pectoral skeleton including median ventral, right and left anterior dorsolateral plates, anterior ventrolateral plates, dorsal central 1 and ventral central 1 plates; NUFV 895, right mixilateral plate. DIAGNOSIS. — Antiarch referred to Asterolepis by the presence of an anterior median dorsal plate that broadly overlaps the mixilateral plates (Moloshnikov 2008). Distinguished from previously described species by the following combination of anatomical features: 1) a tall, rounded midline crest that rises from a position near the tergal angle of the anterior median dorsal plate and loses most of its height before reaching the posterior median dorsal plate and (2) a midline crest of the posterior median dorsal plate that decreases in height cranial to caudal. REMARKS Because the new species is ... |
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