Cerodrillia thea Dall 1884
Creators: name: Fallon, Phillip J.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Drilliidae
Cerodrillia
Cerodrillia thea

description: Cerodrillia thea (Dall, 1884)
(Plates 34, 35)
Drillia thea Dall, 1884: 328, pl. 10, fig. 5): Dall (1889a: 91); Dall (1889b: 98–99); Maury (1922: 151).
Drillia (Clavus) thea (Dall, 1884): Tryon (1884: 189: pl. 34, fig. 1).
Pleurotoma thea (Dall, 1884): Simpson (1887c: 55); Paetel (1888).
Cerodrillia (Cerodrillia) thea (Dall, 1884): Bartsch & Rehder (1939: 128–129).
Cerodrillia thea (Dall, 1884): Perry (1940: 165, pl. 38, fig. 261); Perry & Schwengel (1955: 182, pl. 38, fig. 261); Tabb & Manning (1961: 581); Powell (1966: 16, fig. D90); Abbott (1968: 168, fig. 10); Sarasúa (1970: 1); Hoerle (1970: 56); Morris (1973: 247, pl. 68, fig. 7); Abbott (1974: 271, text fig. 3023); Campbell et al. (1975); Emerson & Jacobson (1976: 171: pl. 25, fig. 29); Rehder (1981); Kaicher (1984: card 3900); Abbott & Morris (1995: 257, fig. 63); Shelton (1997); Redfern (2001: 123, pl. 55, fig. 512); Leal (2005: 16, text photo); Williams (2005; 2009: 1522); Redfern (2013: 218, fig. 609).
Not this species, or unverified extralimital reports.
Cerodrillia thea (Dall, 1884): Dall & Simpson (1901: 387 [Puerto Rico]); Parker & Curray (1956: 2433 [Texas]); Nowell- Usticke (1959: 82 [St Croix]; Warmke & Abbott (1961: 140, pl. 25, fig. i [fig. i is of C. thea, but they cite Dall & Simson’s paper for the record wherein 2 broken specimens were found, unlike that depicted in the photo]). Ekdale (1974: 650 [Quintana Roo, Mexico]): Rios (1975: 132: pl. 40, fig. 595 [São Paulo state, Brazil]); Treece (1980: 562 [NE Quintana Roo, Mexico]); Sander & Lalli (1982: 317 [off St. James, Barbados]); Vokes & Vokes (1983: 59, pl. 21, fig. 4 [Campeche Bank; Quintana Roo]); Rios (1985: 138, pl. 47, fig. 632 [Bahia and São Paulo states]); Absalão (1986); Jong & Coomans (1988: 111 [Curaçao]); Rios (1994: 160, pl. 53, fig. 718 [Bahia to São Paulo states]); Díaz (1994: 40 [Tayrona National Park, Colombia]); Diaz & Puyana (1994: 225; pl. 67, fig. 891 [Magdalena Dept., Colombia]); Pointier & Lamy (1998: 159 [Guadeloupe, photo = D. antillensis, n. sp.]); Absalão et al. (2005: 22, fig. 2 [Brazil]); Absalão (2007 [Abrolhos Bank and Bahia state]); Rios (2009: 311, fig. 786 [São Paulo state]); Lee (2009: 124, species 593 [St. Johns Co., E Florida; photo and habitat description = C. ambigua, n. sp.]); Massemin et al. (2009: 204 [Martinique; Guyana, neither photo is of C. thea; right-most photo = D. antillensis, n. sp.]); Daccarett & Bossio (2011: 129, fig. 783 [Colombia; fig. not of C. thea]).
Type material. Two syntypes: 14.7 x 5.5 and 15.7 x 5.8 mm (USNM 35976). The syntypes are depicted in Plate 34, Figs. 1, 12.
Type locality. Sarasota Bay, W Florida, on mud flats between tides.
Other material examined. An additional 67 specimens were examined: W Florida: 1 spec., 13.2 x 5.1 mm, Gulf of Mexico, J. Moore! (USNM 900135); 4 spec., 10.1 x 4.0, 10.4 x 4.4, 11.4 x 4.3 and 11.5 x 4.5 mm (last 2 miss. protoconchs), dredged at 73 m, W of Egmont Key, Hillsborough Co., Jim Moore! Aug 1963 (H.G. Lee coll.); 3 spec., 16.9 x 6.0, 14.2 x 5.1 & 16.0 x 6.0 mm, Sarasota Bay, Sarasota Co., W. Guynup! (USNM 890212); 1 spec., 13.7 x 5.2 mm, on sand flat, Tarpon Bay, Sanibel I., Lee Co., E. García! Jan 1968 (EFG 2414); 1 spec., 14.4 x 5.7 mm, Kunyon Key, Gulf side, Sanibel I., E. Sarkin! (USNM 900138); 2 spec., 13.0 x 4.8 & 11.5 x 4.7 mm, Tarpon Bay, Sanibel I., C. Withrow! 8 Aug 1962 (USNM 900137); 1 spec., 13.4 x 5.0 mm, in 26 m, 43 km WSW of Ft. Myers, Lee Co., R. Masino! (author’s coll.); 4 spec., best is 7.2 x 2.9 mm, in 9–11 m, off Naples, Collier Co., D. Steger! (ANSP 306487). Florida Keys: 5 spec., 10.5 x 3.9, 11.9 x 4.4, 11.8 x 4.2, 13.3 x 4.2 & 10.0 x 3.7 mm, Key Largo, F. Bayer! (USNM 890154); 3 spec., 13.2 x 5.0, 13.1 x 4.6 & 10.0 x 3.5 mm, Boot Key, Marathon, Jo & Rusty Bennett! (EFG 11547); 2 spec., 11.8 x 4.8 & 12.1 x 3.8 mm, Long Key, 12 Nov 1997 (USNM 900136); 1 spec., 9.7 x 3.9 mm, Crawl Key, M. Teskey! 26 Apr 1981 (USNM 900140); 1 spec., 10.5 x 4.6 mm, Boca Chica Key (author’s coll.); 2 spec., 10.6 x 4.2 & 9.6 x 4.0 mm, in 0.9 m, Little Torch Key, M. Williams! 3 Jun 1978 (EFG 17292); 7 spec., 11.9 x 4.5, 10.1 x 4.0, 11.3 x 4.7, 10.1 x 4.0, 8.4 x 3.6, 8.9 x 3.5 & 8.7 x 3.5 mm, Little Torch Key, E. Shuller & J. Tysor 3–5 Jun 2012 (E. Shuller coll.); 2 spec., 9.8 x 3.5 & 10.1 x 4.3 mm, in 0.3–0.9 m, Little Torch Key, M. Teskey! 1978 (USNM 900134); 5 spec., 3 best:, 9.2 x 3.9, 8.7 x 3.7 and 8.0 x 3.2 mm, in shallow water, N shore, Content Keys, H.G. Lee! 1 Oct 1983 (H.G. Lee coll.); 3 spec., 9.6 x 3.8, 9.0 x 3.3 & 8.6 x 3.2 mm, in 3–5 m at mouth of Tavernier Creek, ocean side, SE Tavernier Key, W.H.M McCullagh, Jr.! 28 Dec 1975 (H.G. Lee coll.); 2 spec., 10.1 x 4.0 & 11.6 x 4.6 mm, in 0.9–1.2 m at low tide Harry Harris Park, Tavernier Key, A. Borgia! 17 Nov 2010 (author’s coll.); 2 spec., 14.4 x 5.6 & 15.1 x 6.0 mm, in 13 m, 14 km N of Key West, G. Mackintosh! 14 Jan 1993 (author’s coll.). E Florida: 1 spec., 10.5 x 4.2 mm, off Stiltsville, Miami-Dade Co. (USNM 900141); 1 spec., 12.9 x 5.4 mm (no proto.), Peanut I., Palm Beach Co., C.H. Hebert! 1952 (H.G. Lee coll.). Bahama Is.: 1 spec., 12.2 x 5.0 mm, Bimini Is. (USNM 900139); 1 spec., 13.0 x 5.3 mm, beach drift, Bimini Is., H. Houg! 8 Sep 1987 (H.G. Lee coll.); 3 spec., 11.9 x 4.6, 12.1 x 4.9 & 13.0 x 4.6 mm, 2.4 km N of Savanna Sound turnoff, Tenbay Beach, Eleuthera I. (author’s coll.); 1 spec., 11.4 x 4.4 mm, beach drift, 300 m N of Current Cut, Eleuthera I., H.G. Lee! May 1978 (H.G. Lee coll.). Cuba: 2 spec., 9.3 x 3.5 & 8.0 x 3.2 mm, in 2–5m, Barrera Exped. Sta. 212, Cardenas Bay, Matanzas Prov. (USNM 411327); 3 spec., 13.3 x 5.1, 12.1 x 4.8 & 10.9 x 4.1 mm, in 5–7 m, bay side, Hicacos Peninsula, Matanzas Prov., I.E. DuPont Exp. 1931, Pilsbry! (ANSP 157724).
Range and habitat. W Florida (Okaloosa Co. and southward); Florida Keys; E Florida (Palm Beach Co. and southward); Bahama Is. (Grand Bahama I., Bimini Is., Abaco I.; Eleuthera I.); Cuba (north coast of Matanzas Prov.). Localities appearing in the published literature that are just outside this range and have yet to be confirmed are: North Carolina; E Florida (north of Palm Beach Co.); Alabama (Gulf coast); Louisiana; and Cuba (west and south of its NW coast). Reports of specimens from further afield are unlikely to be C. thea. Habitat reports are from the littoral zone to 27 m depths, from locations around sand bars of inside waters (Perry, 1940b: 165), in tide pools at low tide, bays, and from shallower waters offshore. Substrates range widely from mud flats, to sand and rubble bottoms in grass.
Description. Shell small (to 16.9 mm), narrowly to stoutly fusiform; truncate anteriorly, body whorl about 60% of length, and surface glossy; sculpture of axial ribs; whorls convex, suture impressed. Protoconch of approximately 1½–1¾ smooth, semi-translucent whorls, the first partially immersed in the second at its tip. Axial sculpture of well-spaced ribs, 7–9 on penultimate, 4–8 on last to varix, interspaces about twice their width, ribs run from suture-to-suture on spire whorls, evanesce early on shell base, straight to oblique, broadest and highest, sometimes knob-like, at shell periphery, lower, narrower, sometime obsolete on last whorl, and hooked to the left in sulcal area; rib profile convex, periphery below mid whorl on spire whorls; rib crests round at periphery and ridged on shoulder. Spiral sculpture limited to faint spiral ridges on shell base, below periphery, and distinct ridges on anterior fasciole. Sulcus obscure in some, marked by the presence of curved growth striae, to well-marked by reduced ribs, narrowed and curved, or obsolete ribs as in the later whorls of larger specimens. Vari x cup handlelike, ¼-turn from edge of outer lip. Outer lip thin, with a strengthening rib very close to lip edge in mature specimens; edge forming an arc from and congruent with anal sulcus to the stromboid notch; stromboid notch shallow. Anal sulcus deep, U-shaped, located on shoulder slightly set off from suture; sides of sinus divergent. Inner lip margined, thick along anterior canal, wider but thinner on parietal wall, and forming a lobe at junction with outer lip. Anterior canal very short, bent slightly to the right viewed ventrally, open and unnotched. Color light to dark caramel; usually rib crests just white, but sometimes a continuous mid-whorl white band present, and rarely a second, thin white band on shell base.
Remarks. Nomenclatural. Some references site the year of authorship of this name as 1883, but Dall’s description was published in 1884 (Jan), not 1883, as stated on the original publication (Rosenberg, 2009). Taxonomy. Cerodrillia thea is typical for Cerodrillia in possessing ribs from suture-to-suture, a cup-handle-like varix, and spiral sculpture limited to the shell base. Cerodrillia thea was included in Cerodrillia by Bartsch & Rehder (1939: 128–129) in their original description. Some specimens do exhibit characteristics of Douglassia, namely the significant reduction of ribs in the sulcus, even absent on the last whorls of older specimens. Variability. The average length of 68 specimens is 11.28 mm (5.3–16.9 mm), and their average W/L is 0.390. C. thea is narrow for Cerodrillia, most members of the genus have a W/L> 0.40. Individual specimens are uniformly colored, ranging from very dark brown to fairly light (Plate 35, Fig. 4). The color of the syntype depicted in Plate 34, Fig. 1 is typical of the species. Geographic variation is exhibited by this species and may be due to population isolation and habitat influences. Specimens from the Bahama Is. have more angular varices; those from the Florida Keys are smaller and darker, and from the central western coast of Florida are largest and generally colored like the types. Identification. Cerodrillia thea has a shell that is high-spired and uniformly light to dark caramel in color with lighter ribs that are noticeably oblique, traits that distinguish it from species with which it is often confused. C. thea is most similar to C. harryleei, new species and C. sanibelensis, new species, both from W Florida. From C. harryleei it differs in possessing slightly more ribs that are more oblique and less nodulose (7–9 versus 5–6 on the penultimate whorl). Also, C. harryleei has a faint brown spiral stripe in specimens examined so far, which is absent in C. thea. From C. sanibelensis it differs in possessing a narrower shell (average W/ L ratio = 0.390 versus 0.405), slightly more ribs that are more oblique (7–9 versus 6–7 on the penultimate whorl of individuals with varices), and darker color (light to dark caramel versus white to light orange brown).
description: Published as part of Fallon, Phillip J., 2016, Taxonomic review of tropical western Atlantic shallow water Drilliidae (Mollusca: Gastropoda: Conoidea) including descriptions of 100 new species, pp. 1-363 in Zootaxa 4090 (1) on pages 80-84, DOI: 10.11646/zootaxa.4090.1.1, http://zenodo.org/record/263299