Costoanachis Sacco, 1890

Harzhauser, Mathias & Landau, Bernard M., 2021, The Columbellidae (Gastropoda, Buccinoidea) in the Miocene Paratethys Sea — striking diversity of a negelected group, Zootaxa 5025 (1), pp. 1-75 : 13-14

Costoanachis Sacco, 1890

Type species. Costoanachis saccostata Radwin, 1977 [= Columbella (Anachis) turrita Sacco, 1890 , non Columbella turrita Sowerby, 1832 ]; subsequent designation by Pace (1902: 43). Miocene, Italy.

= Ecostoanachis Sacco, 1890 , type species Columbella cythera Doderlein, 1863 , subsequent designation by Pace 1902: 44; middle Miocene, Italy (see Sacco 1890b: 59; Doderlein 1863: 24).

Discussion. Radwin (1977: 120) characterised Costoanachis as small to moderately-sized fusiform with moderately high and acute spire with flat whorls and prominent axial ribs. Aperture moderately wide, columellar callus weakly denticulate; outer lip denticulate; short siphonal canal. Although we agree with this brief diagnosis, Costoanachis of Radwin (1977) is probably polyphyletic as it includes also extant species with spiral sculpture on the spire whorls.

Herein, we restrict Costoanachis to species without spiral sculpture on spire whorls. In addition, all species discussed below as Costoanachis develop large, low conical, multispiral protoconchs and we consider this morphology to be typical for Costoanachis as well. This is largely in accordance with the original concept of Sacco (1890b: 57) who based Costoanachis on the Burdigalian Columbella (Anachis) turrita Sacco, 1890 [= Costoanachis saccostata Radwin, 1977 ]. In addition, Sacco (1890b) described C. corrugata Brocchi 1814 (Zanclean) , C. magnicostata Sacco 1890 (Tortonian) , C. parva Sacco, 1890 (Langhian) , C. procorrugata Sacco 1890 (Langhian) and C. turbinellus Sacco 1890 (Zanclean) in his new section Costoanachis . In some species, the axial sculpture may be reduced on the last whorl (e.g., C. guembeli ( Hoernes & Auinger, 1880) . Therefore, we include also C. semicostata Sacco, 1890 and C. semiplicata Sacco, 1890 in Costoanachis , which have originally been treated as Ecostoanachis by Sacco (1890b).

An exception to the original concept of Sacco (1890b) is C. rectocostata Sacco 1890 , which has spiral sculpture between the axial ribs. This species is removed herein from Costoanachis and is placed in Zafrona Iredale, 1916 (see below).

Overall, Costoanachis as understood herein, is a Neogene circum-Mediterranean genus with occurrences in the Proto-Mediterranean Sea, the Paratethys Sea, the northeastern Atlantic and the North Sea. Recent species of Costoanachis , however, are described from the tropical/subtropical American Atlantic and Pacific, the subtropical/ tropical western Atlantic and Mediterranean Sea and the Indo-West Pacific. This wide distribution strongly suggests that Costoanachis as used in zoological literature is polyphyletic.