Epitonium minuticostum
(de Boury, 1912)
Description:
Dimensions range from 3 mm - 35 mm high and 1.5 mm - 17 mm wide.
Width to height ratio: 0.5:1 ~ 0.49:1
Shell: elongate-conical; rather fragile; microscopic to moderately small. Exterior colour horn colour or white, slightly translucent, costae white. About 11 whorls, well-rounded, completely disjointed, connected only by the costae in the upper whorls; protoconch with 0-3 whorls brown, glassy, smooth, acute, smooth; teleoconch with 4-8 whorls rapidly enlarging, strongly convex. Suture deep, very deep suture. Umbilicate: narrowly perforate, minutely perforate, narrow but deep. Approximately 13 - 21 costae on the body whorl. Costae are with wider inter-spaces, narrow, thin, smooth,, low, sharp. Occasional varix appearing randomly on the shell. Costae not generally continuous; short, sharp spine in front of suture, with a small sharp short spine a little distance in front of the suture, not spinose; reflected; not continuous. Intercostal spaces on the last whorl, about 20 sharply defined threads, mostly with wider interspaces, in which there are fine spiral striulae; there is a smooth space in front of the suture and another around theumbilicus, spiral sculpture of uniform, very fine, close-set threads covering the whole whorl between the varices, dense spiral striae. Interstices with approximately 20 spiral striae per whorl. Base concave, entirely lacking a circumbasal funicle. Aperture oval, lip reflected; outer lip thin; inner lip continuous and leaf-like. Operculum horny, dark brown, paucispiral.
Distribution:
Baja California to the Galápagos [DuShane 1974: 22]
Habitat:
Dredged on sand and broken shell bottom. 18 to 137 m. [DuShane, 1974:22]
Etymology:
[latin] from minutus = small or fine and costatum = rib, in reference to the small fine costae on the shell
Type Material:
Holotype: Scala ( Viciniscalaf) minuticosta De Boury: Zoologisches Mus. Berlin, East Germany, no. 2578 (fide R. Kilias pers. comm. 1978), Univ. Berlin: West Colombia. Epitonium clarki T. S. Oldroyd: Holotype, SU 5948 (now at CAS); Santa Monica, California. Pleistocene. Epitonium cedrosensis Jordan and Hertlein: Holotype CAS (GTC) 2116. Paratypes CAS (GTC) 2117-2120; Bernstein's Abalone Camp, Cedros Island, Baja California Norte, Mexico. Pliocene. Epitonium dallasi Jordan and Hertlein: Holotype CAS (GTC) 2122; Turtle Bay, Baja California Sur, Mexico.Pliocene. Epitonium nesioticum Dall & Ochsner. Holotype CAS (GTC) 2928; Paratypes CAS (GTC) 2929, 2930, 2931; Isla Isabela (Albemarle Island), Galapagos Islands, Ecuador. Pleistocene. for Epitonium minuticostum (de Boury, 1912). [DuShane, H., 1979]
Holotype: U. S. Nat. Mus. Cat. No. 96821 [as Epitonium pacis Dall, 1917] - Locality: La Paz, Lower California 10 to 45 fathoms. [18.3-82.3m]. [Dall, W. H., 1917]
Holotype: U.S. Nat. Mus. Cat. No. 211786a [as Epitonium onchodes Dall, 1917] - Locality: Panama Bay in 62 fathoms [113.4m], sand. [Dall, W. H., 1917]
Types: Holotype: Scala (Viciniscala?) minuticosta Zool. Mus. Berlin, Germany, no. 302 (fide deBoury). Epitonium pacis: holotype, USNM 96821 La Paz, Gulf of California, Mexico. Epitonium onchodes: holotype, USNM 211786a, Panama Bay. Epitonium clarki: holotype, SU[PTC] 5948, Santa Monica, California. Epitonium cedrosensis: holotype, CAS[GTC] 2116, Bernstein's Abalone camp, Cedros Island, Mexico. Epitonium dallasi: holotype, CAS[GTC] 2122, Turtle Bay, Baja California, Mexico. Epitonium nesioticum: holotype, CAS[GTC] 2928, Isla Isabela (Albemarle Island), Galápagos Islands, Ecuador for Epitonium minuticostum (de Boury, 1912). [DuShane, H., 1974]
Holotype: ZMB 2578 [as Scala minuticosta de Boury, 1912: ~ Epitonium pacis Dall, 1917; ~ Epitonium onchodes Dall, 1917.] - Locality: West Columbia [sic; = Colombia].. [Brown, L. & Neville, B.D., 2015]
Holotype: USNM 211786a [as Epitonium onchodes Dall, 1917:] - Locality: Panama Bay, 62 fms [= 113 m], sand.. [Brown, L. & Neville, B.D., 2015]
Holotype: USNM 96821 [as Epitonium pacis Dall, 1917:] - Locality: in the vicinity of La Paz, Lower California, Mexico, 10-45 fms [= 18-82 m].. [Brown, L. & Neville, B.D., 2015]

Boury, E. de. (1912). Plate VII. Fig. 1.
Distribution
as listed in source literature
de Boury, E. (1913).

pp: 87.
Shell white, smooth, slightly translucent, rather fragile, elongate-conical, narrowly but deeply umbilicated. Suture fairly oblique, narrow and completely disjointed; in the upper whorls, joined only at the ribs. Embryonic whorls are absent.
The following 7 whorls are strongly convex, adorned with moderately high ribs, fairly spaced, smooth, sharp, and only slightly prominent. Several transverse spiral striae, fairly densely arranged, are present. The last whorl is furnished with 21 ribs. The base is concave, entirely lacking a circumbasal funicle. The columella is not supported by any funicle. Aperture rounded. Inner peristome continuous and leaf-like. Outer peristome thin.
Length: 35 mm; Greatest diameter: 17 mm; Maximum height of whorls: 11 mm.
Habitat: West Columbia. Unique type specimen: Berlin Zoological Museum, no. 302
Dushane, H. (1974).

pp: 22. Fig. 20.
Scala (Viciniscala ?) minuticosta deBoury, 1912.
Holotype, Berliner Zoologisches Museum, Germany, no. 302 (after deBoury, 1912, Journ. de Conchyl. 60 (2) : pit. 7, fig. 1)
length 35 mm, width 17 mm

pp: 22. Fig. 21-26.
Figure 21: Epitonium pciss Dall, 1917. Holotype, USNM 96821; length 12mm; width 6 m
Figure 22: Epitonium clarki T. S. Oldroyd, 1921. Holotype, SU [PTC] 5948 (Pleistocene fossil) ; length 19mm; width 8mm
Figure 23: Epitonium onchodes Dall, 191 7. Holotype, USNM 211 786a; length 3 mm; width i-Jmm X 20
Figure 24: Epitonium dallasi Jordan & Hertlein, 1926. Holotype, CAS[GTC] 2122; length 7 mm; width 4 mm
Figure 25: Epitonium cedrosensis Jordan & Hertlein, 1926. Holo- type, CAS[GTC] 21 16 (Pliocene fossil); length 8mm; width 3 mm
Figure 26: Epitonium nesioticum Dall & Ochsner, 1928. Holotype, CAS[GTC] 2928 (not Dentiscala nesiotica Dall, 1917); length 7J mm; width 3.3mm
Dushane, H. (1979).

pp: 103. Fig. 13.
Figure 13: Scala (Viciniscala) minuticosta DeBoury, 1912. Holo- type: Zool. Museum Berlin, East Germany, no. 2578 {fide R. Kilias. Univ. Berlin). Photograph after DeBoury, 1912, Journ. Conchyl. 60 (2) : pit. 7, fig. 1; length, 35mm; width 17 mm



