Nikolivia, KARATAJUTE-TALIMAA, 1978

Burrow, Carole Jan, Murphy, Michael & Turner, Susan, 2023, Late Silurian to earliest Devonian vertebrate biostratigraphy of the Birch Creek II section, Roberts Mountains, Nevada, U. S. A., PaleoBios 40 (4), pp. 1-32 : 23

publication ID

https://doi.org/ 10.5070/P940454153

publication LSID

lsid:zoobank.org:pub:58312615-0833-432E-BF5D-3DFFBF361AAA

DOI

https://doi.org/10.5281/zenodo.11489408

persistent identifier

https://treatment.plazi.org/id/B21CD55B-FFC6-FFF8-59B5-8D63FB182284

treatment provided by

Felipe

scientific name

Nikolivia
status

 

NIKOLIVIA KARATAJŪTĖ-TALIMAA, 1978

Type species — Nikolivia balabayi Karatajūtė-Talimaa, 1978.

NIKOLIVIA SPP.

( FIG. 7E–J View Figure 7 ; TABLE 1 View Table 1 ; SUPPL. 1, FIGS. 5 View Figure 5 , 9 View Figure 9 , 20, 25)

Referred material —Rare except for one level; c. 15 specimens from section BC II: one scale AMF97875 from 402’ (122.5 m)– this specimen is missing; c. 11 from 430.5’ (131.2 m), 456.5’ (139.1 m); level 527.25’ (160.7 m); one specimen from level 591.5’ (180.3 m): Roberts Mountains Formation .

Description and comparison —AMF97875 and the other Nikolivia scales from BC II, notably from 430.5’, resemble scales of N. gutta , N. aligera Karatajūtė-Talimaa, 2002 ( Fig. 7 View Figure 7 A-E), and N. auriculata Märss et al., 2002 ( Fig. 7F View Figure 7 ). These nikoliid taxa are found in the early Lochkovian elsewhere ( Märss et al. 2007). The specimen that Parkes (2005, fig. 22.17, 18; Fig. 7G View Figure 7 ) captioned as Amaltheolepis sp. cf. A. winsnesi from 402’ is a typical nikoliviid scale, bilaterally symmetrical, small (0.4 mm long x 0.3 mm wide) and rounded. The central squat teardrop-shaped crown section is smooth and rounded anteriorly and raised slightly, curving to a posterior point with three short anterior ridges that extend less than a quarter scale length. There is a pair of lateral flattened lappets with a simple but slightly imperfect (damaged?) rim with small scallop-shaped concavities, two on one side and one on the other. The central surface of the crown is smooth with a broad middle raised ridge extending from the midpoint near the base to the posterior point. The neck is smooth and low. The anteriorly placed base is a rounded torus: relatively smooth, deep, and mature with a smaller central rounded pulp opening. One possible thelodont specimen (Suppl. 1, fig. 25:?) from level 591.5’ just above the S–D boundary appears typical of Nikolivia gutta Karatajūtė-Talimaa, 1978 with its smooth heart-shaped crown.

Remarks — Parkes (1995) interestingly misidentified scale AMF97875 ( Fig. 7G View Figure 7 ) as an amaltheolepid. Here we refer it to Nikolivia sp. But there are not enough scales in the Nevadan material to judge the variation. Nikoliviid scales are typical of the Early Devonian (Lochkovian) in Europe, and elsewhere in North America ( Märss et al. 2007). The small regular concavities on the rim of the lateral lappets of the specimen might be damage made in handling the specimen or a pathological feature as they resemble bite-marks, but this has not been seen elsewhere. Lepidophagy is common in modern bony fishes and it is feasible that the scale was attacked in life or alternatively post-mortem by another fish or even by an unknown invertebrate.

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