Drepanoistodus basiovalis ( Sergeeva, 1963 )

Zhen, Yong Yi, Percival, Ian G. & Webby, Barry D., 2003, Early Ordovician Conodonts from Far Western New South Wales, Australia, Records of the Australian Museum 55 (2), pp. 169-220 : 191

publication ID

https://doi.org/ 10.3853/j.0067-1975.55.2003.1383

persistent identifier

https://treatment.plazi.org/id/37439A20-CB3D-FF2B-FF24-FB78FBC2FA77

treatment provided by

Felipe

scientific name

Drepanoistodus basiovalis ( Sergeeva, 1963 )
status

 

Drepanoistodus basiovalis ( Sergeeva, 1963)

Fig. 14A–K View Fig

Oistodus basiovalis Sergeeva, 1963: 96 , pl. 7, figs. 6, 7, text-fig. 3.

Drepanoistodus basiovalis Löfgren, 1978: 55 , pl. 1, figs. 11–17, fig. 26B,C (cum syn.).

Drepanoistodus suberectus Cooper, 1981: 164 , pl. 26, figs. 1, 2, 6.

Drepanoistodus basiovalis .–Johnston & Barnes, 2000: 18, pl. 11, figs. 10, 11, 15, 16 (cum syn.).

Material. Thirteen specimens (4 P, 1 M, 1 Sa, 3 Sb, 4 Sc) from limestone nodules within shales of the upper Yandaminta Quartzite, and 123 specimens (11 P, 31 M, 21 Sa, 41 Sb, 19 Sc) from the overlying Tabita Formation at Mount Arrowsmith ; 21 specimens (3 P, 4 Sa, 8 Sb, 6 Sc) from unnamed dolomitic limestone unit at Koonenberry Gap .

Description. Apparatus quinquimembrate, all elements are hyaline, laterally compressed with sharp anterior and posterior margins, non-costate lateral faces, and have an open basal cavity. The P element ( Fig. 14A,B,D–F,H View Fig ) is asymmetrical with a reclined cusp and an extended anterobasal corner, triangular in outline. The M element is geniculate with a short outer lateral process, and a rounded inner lateral corner; a mid-carina may develop on the anterior and posterior faces ( Fig. 14J,K View Fig ). The S elements consist of a symmetrical (or nearly so) Sa element with an erect cusp ( Fig. 14G View Fig ), an asymmetrical Sb element with a reclined cusp and an oval-shaped opening of the basal cavity ( Fig. 14C View Fig ), and an asymmetrical Sc element with a strongly recurved, more laterally compressed cusp, having a narrower opening of the basal cavity ( Fig. 14I View Fig ).

Remarks. The definition of this widely distributed species given by Löfgren (1978) is followed here. However, the element with an outer lateral costa ( Löfgren, 1978, pl. 1, fig. 12) is not recognized in our collections. The P element corresponds to the scandodiform element of many previous authors (e.g., Stouge & Bagnoli, 1990, pl. 5, fig. 19). Compared with their material from Sweden, M elements from western New South Wales are characterized by a shorter outer lateral process.

Kingdom

Animalia

Phylum

Chordata

Class

Conodonta

Order

Distacodontina

Family

Drepanoistodontidae

Genus

Drepanoistodus

Loc

Drepanoistodus basiovalis ( Sergeeva, 1963 )

Zhen, Yong Yi, Percival, Ian G. & Webby, Barry D. 2003
2003
Loc

Drepanoistodus suberectus

Cooper, B 1981: 164
1981
Loc

Drepanoistodus basiovalis Löfgren, 1978: 55

Lofgren, A 1978: 55
1978
Loc

Oistodus basiovalis

Sergeeva, S 1963: 96
1963
Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF