Zeidora geigeri

Helwerda, Renate A. & Wesselingh, Frank P., 2014, Revision of Scissurellidae, Anatomidae and Fissurellidae (Gastropoda: Vetigastropoda) from the Plio-Pleistocene of the Philippines, Zootaxa 3838 (2), pp. 183-194 : 191-192

publication ID	https://doi.org/ 10.11646/zootaxa.3838.2.3
publication LSID	lsid:zoobank.org:pub:A3B0A5D4-D989-4804-9501-CE4423F146C9
DOI	https://doi.org/10.5281/zenodo.5625979
persistent identifier	https://treatment.plazi.org/id/039287E3-FFF7-FFCA-FF41-F9C1FC43FD4B
treatment provided by	Plazi
scientific name	Zeidora geigeri
status

Treatment

Zeidora geigeri View in CoL nov. spec.

( Figure 12 View FIGURES 10 – 12. 10 )

Type material. Holotype RGM 961.724.

Type locality. Anda 2, Pangasinan, Philippines, Santa Cruz Formation, Pliocene or Early Pleistocene, 16º17′24.8′′ N 119º56′11.8′′ E.

Derivatio nominis. Named after Daniel L. Geiger (Santa Barbara Museum of Natural History), authority on Vetigastropoda .

Diagnosis. Shell patelliform, elongated; L> 4.54 mm; H 2.25 mm; W> 3.50 mm; apex posterior, low, not extending beyond shell outline; protoconch nucleus with anastomosing ridges; teleoconch sculpture of about 80 primary radial ribs, commarginal ribs forming small nodules on radial ribs; selenizone distinct; posterior septum narrow.

Description. Shell small, ovate, whitish, fragile. Spire low, located posteriorly, slightly twisted to right side, nearly reaching but not extending beyond shell outline. Protoconch of 1.1 whorls, located on right side of spire, terminated by a distinct varix. Nucleus sculptured with anastomosing ridges. Teleoconch of 0.9 whorl, elongated, anterior and right side broken. Teleoconch surface sculptured with about 80 fine radial ribs, many commarginal ribs, forming reticulate network with small nodules at intersections. Margins crenulated by radial ribs, crenulations strongest at posteroventral margin. Selenizone moderately narrow, sculptured with curved commarginal ribs, distinct keels on each side. Inner shell surface smooth, shiny. Internal septum located posteriorly, narrow, with slightly thickened rim.

Differentiation. There are fourteen Recent species and two fossil species of Zeidora . All of these species differ from Zeidora geigeri nov. spec. because they have a much wider septum and/or a spire that extends beyond the posteroventral margin. Z. tasmanica ( Beddome, 1883) from Tasmania, Recent, is most similar in sculpture and shape of the spire, but it has a wider septum.

Remarks. The combination of a narrow septum and a spire that does not extend beyond the posteroventral margin in Z. geigeri nov. spec. makes this species unique among the Zeidora species and therefore the description of a new species is justified although it is based on a single, incomplete specimen. The specimen shows enough features for re-identification of additional material found in the future.