Triadocypris spitzbergensis Weitschat 1983

Kornicker, Louis S., Van, Barry W. M., Bakel, Fraaije, René H. B. & Jagt, John W. M., 2006, Revision of Mesozoic Myodocopina (Ostracoda) and a new genus and species, Mesoleberis hollandica, from the Upper Cretaceous of Belgium and The Netherlands, Zootaxa 1246, pp. 15-54 : 35-36

Triadocypris spitzbergensis Weitschat 1983 a

Fig. 3 L, M

Triadocypris spitzbergensis Weitschat 1983a:309 –323, 10 figs.—1983b:127–138.— Weitschat & Guhl 1994:17 –31, figs. 1, 9. — Cohen et al. 1998:258.— Kornicker & Sohn 2000:22. Holotype

Geologisch­Paläontologisches Institut und Museum, University of Hamburg (GPIHM), no. 2558.

Type locality

Sticky Keep Formation, Lower Triassic (subrobustus Zone); Flowerdalen, Spitsbergen, lat. 78°N, long. 17°E ( Weitschat 1983b).

Material

No material examined herein.

Distribution

Triassic of Spitsbergen.

Diagnosis (from Weitschat 1983b)

Myodocopid with carapace 2.9–3.1 mm long; oval in lateral view. With small rostrum and shallow rostral incisur. Posterior margin forming very slight angle at midpoint, but fairly evenly rounded. Left valve overlaps right. Delicate dentition present along dorsal margin of each valve. Ornamentation composed of small, closely spaced pits. Gills welldeveloped, with three lobes on each side. Lateral eye with about 20 ommatidia.

Foreign attachments. Weitschat & Guhl (1994:17) described fossil ciliates attached to the body of one specimen.

Comparisons

Carapace differs from that of M. hollandica in having a shallower incisure and a different arrangement of central adductor muscle scars.

Remarks

Weitschat (1983a:314) referred this species to the Cypridinidae ; however, the presence of five dorsal bristles on the second article of the first antenna indicates that the species belongs in the Cylindroleberididae . Weitschat (1983a:314) proposed a new subfamily Triadocypridininae Weitschat 1983a for T. spitzbergensis , and Cohen et al. (1998:254, 259) raised the status to family level as Triadocyprididae. The soft parts of T. spitzbergensis differ in some respects from those of extant Cylindroleberididae ( Cohen et al. 1998:258, 259), and the species may be a new family or subfamily. Nevertheless, the senior author believes it conservative at this time to interpret the differences as variations within the Cylindroleberididae . Several species known only from specimens without soft parts but with carapaces somewhat similar to that of T. spitzbergensis have been referred tentatively to Triadocypris .

Figures

FIGURE 3. Triadogigantocypris balatonica Monostori 1991: A, left lateral view of carapace, length 12 mm; B, detail of central muscle scars from A. Triadogigantocypris donzei (Neale 1976): C, lateral view of male carapace, length 1.065 mm; D, lateral view of female carapace, length 1.117 mm; E, central adductor muscle scars, left valve. Triadogigantocypris koninckiana (Bosquet 1847): F, G, I, lateral views of 3 right valves; H, lateral view, left valve. Triadogigantocypris ovulata (Bosquet 1847): J, left lateral view of carapace, length 1.4 mm. Triadogigantocypris limburgensis (Van Veen 1936): K, lateral view, right valve. Triadocypris spitzbergensis Weitschat 1983 a: L, lateral view of carapace, length 3.1 mm; M, central adductor muscle scars left valve. Size of specimens given if stated in original description.