Radioporacanthodes scheii, (SPJELDNAES, 1967)

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 : 8

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.11488268

persistent identifier

https://treatment.plazi.org/id/B21CD55B-FFD7-FFE9-59F6-8C8BFBA8220F

treatment provided by

Felipe

scientific name

Radioporacanthodes scheii
status

 

RADIOPORACANTHODES SCHEII ( SPJELDNAES, 1967)

( FIG. 2 View Figure 2 CC–EE; TABLE 1 View Table 1 ; SUPPL. 1, FIGS. 2 View Figure 2 , 3 View Figure 3 , 5 View Figure 5 , 9 View Figure 9 –13)

Ischnacanthus? Scheii Spjeldnaes 1967 , 807, figs. 1–3, pl. 1.

Radioporacanthodes scheii ; Burrow 2013, 947, figs. 2-6.

Diagnosis —see Burrow (2013).

Type material — The holotype is fin spine CMN55213 About CMN , in a block with other fin spines, jaw fragments and scales considered to be conspecific; from the northwest side of Irene Bay , Ellesmere Island , arctic Canada, Devon Island Formation (Přidolí? or early Lochkovian) .

Referred specimens —Rare scales recognized at levels 395’ (120.4 m), 424.9’ (129.5 m), 430.5’ (131.2 m), 456.5′–471′ (139.1-143.6 m) in the BC II section, including UCR 10750-1, -5 (level 456.5’= 139.1 m): Roberts Mountains Formation.

Description —These scales are characterised by regularly spaced short sharp ridges along the anterior edge of the crown, without a median sulcus. Pore openings are relatively small, with a maximum of six subparallel rows running back along the posterior half of the crown ( Fig. 2 View Figure 2 CC-EE). The undersurface of the posterior crown has the large canal openings characteristic of this family (not illustrated). The small pores on the crown surface are not always visible with a light microscope, and some scale varieties lack pores.

Comparison — Burrow (2013) reassigned this species from “ Ischnacanthus ?” to Radioporacanthodes based on presence of a pore canal system in the crown of most scales, while also recognising that some variants lack a pore canal system. The BC II scales show some similarity with those of Poracanthodes canadensis in having many short ridges along the anterior edge of the crown, but differ in having a few small pores in subparallel rows on the posterior crown, rather than rows of many pores paralleling the posterolateral crown edges. As noted above, some scales also lack a pore canal system, making it difficult to distinguish these from scales of Gomphonchus volborthi ( Rohon, 1893) , a species resurrected by Vergoossen (1999c), and Gomphonchus sandelensis scales with weakly developed anterior crown ridges. G. volborthi usually has rounded weak anterior ridges, and is probably restricted to older strata ( Vergoossen 1999c). The scales differ from the Gomphonchoporus hoppei variants, which lack a pore canal system in having a smoothly curving anterior crown margin rather than a relatively sharp mid-margin angle ( Vergoossen 1999a, figs. 41–45, 55, 56).

Kingdom

Animalia

Phylum

Chordata

Order

Ischnacantiformes

Family

Poracanthodidae

Genus

Radioporacanthodes

Loc

Radioporacanthodes scheii

Burrow, Carole Jan, Murphy, Michael & Turner, Susan 2023
2023
Loc

Ischnacanthus? Scheii

Spjeldnaes 1967
1967
GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF