Acodus sp.

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 : 182

Acodus sp.

Fig. 8M–Q

Material. 16 specimens ( S elements ) from the Tabita Formation at Mount Arrowsmith; two from unnamed dolomitic limestone unit at Koonenberry Gap .

Remarks. Multicostate coniform elements referred to herein as Acodus sp. are symmetrical or nearly so. At least two types can be distinguished: a quadricostate element ( Fig. 8Q ) with an anterior costa, posterior costa, and one median costa on each lateral side; and a septicostae element ( Fig. 8M–P ) with rounded anterior face, a costa along the posterior margin, and three costa on each lateral side. An additional pentacostate element was also recovered. It has a broad anterior face, two costae on each side and a posterior costa along the posterior margin, and cusp star-shaped in cross section. These specimens show some resemblance to the S elements of Acodus comptus (Branson & Mehl) , but with less strongly developed costae in comparison to that species. They might represent a separate species, but the material available now precludes a complete description.

Figures

Fig. 8. A–J, Bergstroemognathus kirki Stait & Druce, 1993: A, Pa element, AMF120307, M/A11-3, outer lateral view; B, Pb element, AMF120308, M/A11-3, outer lateral view; C, Pb element, AMF120309, M/A11-3, inner lateral view; D, M element, AMF120310, M/ A11-3, posterior view; E, Sa element, AMF120311, Y4–4, posterior view; F, Sa element, AMF120212, Y4–4, anterior view; G, Sb element, AMF120313, Y4–4, posterior view; H, Sc element, AMF120314, M/A11-3, posterior view; I, Sc element, AMF120315, M/ A11-3, anterior view; J, Sd element, AMF120316, M/A11-4, anterior view. K,L, Ansella jemtlandica (Löfgren, 1978): K, Sa element, AMF120317, M/A7, lateral view; L, Sa element, AMF120318, C1612, lateral view. M–Q, Acodus sp.: M–O, septicostae element, AMF120305, M/A11-3, lateral view; P, septicostae element,AMF120304, M/A11-3, lateral view; Q, quadricostae element,AMF120306, M/A11-3, lateral view. Scale bars 100 µm.