Douglassia enae Bartsch, 1934

Fallon, Phillip J., 2016, Taxonomic review of tropical western Atlantic shallow water Drilliidae (Mollusca: Gastropoda: Conoidea) including descriptions of 100 new species, Zootaxa 4090 (1), pp. 1-363 : 138-140

Douglassia enae Bartsch, 1934

(Plate 61)

Douglassia enae Bartsch, 1934: 6 –7, pl. 2, figs. 1–3. Powell (1966: pl. 14, figs. 1–2); Kaicher (1984: card 3956 [holotype erroneously given as USNM 430619]); Williams (2005; 2009: species 1555 [photo of holotype]). Clavus (Douglassia) enae (Bartsch, 1934) : Wenz (1943: 1394; fig. 3939).

Drillia enae (Bartsch, 1934) : Abbott (1974: 270).

Type material. Holotype 16.6 x 7.5 mm (USNM 430289); 2 paratypes from which Bartsch described the protoconch that are also from the type locality: 11.4 x 4.7 & 10.3 x 4.9 mm (USNM 430038). The following, from a different station nearby, were identified as this species by Bartsch in the same article as the original description: 7 spec., 13.2 x 5.7 mm (USNM 429205a), 13.2 x 5.5, 10.0 x 4.5 mm, plus 2 juveniles not measured (USNM 429205) & 2 spec. unaccounted for, in 91 m, R/V Caroline Sta. 104 [off N coast of Puerto Rico; 18°3'4" N, 66°13'20" W and 18°30'10" N, 66°13'50" W].

Type locality. R/V Caroline Sta. 26, between 18°30'20"N, 66°22'05"W and 18°30'30"N, 66°23'05"W [off the N coast of Puerto Rico] in 33–40 fms [60–73 m] depths.

Other material examined. An additional 21 specimens were examined: Guadeloupe: 3 spec., 7.8 x 3.7, 7.7 x 3.6 & 5.5 x 2.8 mm, in 85 m, KARUBENTHOS 2012 Sta. GD55, behind Fajou Islet, Grand Cul-de-Sac Marin, 16°22.5'N, 61°35.5'W, 24 May 2012 (MNHN IM-2012-28045); 2 spec., 7.1 x 3.5 & 7.5 x 3.5 mm, in 95 m, KARUBENTHOS 2012 Sta. GD58, behind Fajou Islet, Grand Cul-de-Sac Marin, 16°22.7'N, 61°35.0'W, 25 May 2012 (MNHN IM-2012-28064); 1 spec., 9.8 x 4.3 mm, in 80 m, KARUBENTHOS 2012 Sta. GD02, Grand Cul-de- Sac Marin, 16°22.6'N, 61°34.1'W, 4 May 2012 (MNHN IM-2012-28035); 1 spec., 8.0 x 3.9 mm, in 80 m, KARUBENTHOS 2012 Sta. GD05, off Fajou Islet., Grand Cul-de-Sac Marin, 16°22.6'N, 61°36.3'W, 5 May 2012 (MNHN IM-2012-28036); 1 spec., 5.0 x 2.6 mm, in 88 m, KARUBENTHOS 2012 Sta. GD59, behind Fajou Islet, Grand Cul-de-Sac Marin, 16°22.6'N, 61°35.4'W, 25 May 2012 (MNHN IM-2012-28046); 1 spec., 7.5 x 3.6 mm, in 65 m, KARUBENTHOS 2012 Sta. GD36, Vieux Bourg, Grand Cul-de-Sac Marin, 16°22.9'N, 61°33.1'W, 18 May 2012 (MNHN IM-2012-28043); 1 spec., 7.3 x 3.6 mm, in 95 m, KARUBENTHOS 2012 Sta. GD60, E Petite-Terre, 16°12.1'N, 61°03.9'W, 26 May 2012 (MNHN-IM-2012-28047); 1 spec., 14.8 x 6.4 mm, in 60 m, KARUBENTHOS 2012 Sta. GD69, Anse Tarare, 16°15.97'N, 61°10.18'W, May 2012 (MNHN IM-2013-9092). This specimen was sequenced and has the following barcode accession numbers:

MNHN Catalog Number Station GenBank accession number BOLD accession number IM-2013-9092 GD69 KT782761 TEMPO007-15 Barbados: 1 spec., 12.3 x 5.2 mm, in 128–183 m, off Jamestown (USNM 900122); 1 spec., 11.4 x 5.0 mm, in 183 m, off St. James, (USNM 900126); 1 spec., 10.7 x 4.8 mm, in 152–183 m, 3.2 km W of Sandy Lane Bay, St. James, D. Hunt! 1988 (UF 470278). Netherlands Antilles: 4 spec., 7.9 x 3.9, 6.8 x 3.4, 8.2 x 3.7 & 8.2 x 3.7 mm, in 130–168 m, in 3 old beer bottles, Sta. 1 off Sea Aquarium, Bapor Kibra, Willemstad, Curaçao (12°04.87'N, 68°53.75'W) M. Harasewych! aboard Curasub , 23 May 2012 (USNM 1199882); 1 spec., 10.8 x 4.7 mm, in old gin bottle at 244–274 m, Sta. 13-04, off Sea Aquarium, Bapor Kibra, Willemstad, Curaçao (12°04'59.51"N, 68°53'56.61"W) C. Baldwin! aboard Curasub , Feb 2013 (USNM 1231395). Brazil: 2 spec., 13.2 x 5.4 & 11.2 x 4.8 mm, in 100–120 m, Minerva seamount, 220 km off Alcobaça, southern Bahia, A. Bianchi! Aug 2012 (P. Stahlschmidt coll.), 1 spec., 12.4 x 5.1 mm, in 30–38 m, off Alcobaça, southern Bahia, A. Bodart! (author’s coll.).

Range and habitat. Puerto Rico (off N coast); Guadeloupe; Barbados (off W coast); Brazil (southern Bahia: off Alcobaça; Minerva seamount). These records extend its known range to southern Bahia state, Brazil. Reported from 55–219 m depths.

Description. Shell small (to 16.6 mm in total length) broadly fusiform or biconic, surface appears waxy smooth, with about 10 moderately convex whorls, acutely shouldered with a large last whorl approximately 65% of total shell length; shell sculpture of prominent ribs. Protoconch of approximately 2¾–3 smooth whorls, the first partially immersed in the second. Axial sculpture of strong ribs that are much reduced to absent in sulcus and evanesce on shell base before the anterior fasciole; number 8–9 on penultimate, 8 on last to varix of mature specimens. Ribs angled at shoulder, elevated, narrower, and with ridged crests, then develop round crests at whorl periphery. First 3–4 whorls have round, not angled shoulders, are greatly reduced or, in larger specimens, end at sulcus on last 2–3 whorls. Varix cup-handle-like immediately behind anal sinus, large, bulging, larger and not angled like preceding ribs. Base of shell appears lopsided when viewed ventrally. Spiral sculpture of fine incised lines or threads on shell base; 8–10 ridges near and on anterior fasciole. Sulcus concave, early whorls with much reduced ribs, mostly absent in later whorls. Outer lip thin, rather narrow, projects out from the varix; with an irregular axial fold on some; edge flexed out at weak anal sinus, waved below; with a shallow stromboid notch. Anal sinus on shoulder, deep, U-shaped, offset from the shell axis by parietal callus; edge of inner lip of sinus flared. Inner lip recumbent, margined, thick anteriorly, thinner on parietal wall widest along columella, narrows on parietal wall, with a thick callus that forms one side of the anal sinus. Lip and callus edge thickened by visible layers of successive deposition, especially in more mature specimens. Anterior canal short, open, un-notched, slightly curved to the right when viewed ventrally, canal tip with a slightly flared marginal lip. Anterior fasciole not swollen. Color white or dirty white with a broad mid-whorl dark golden-brown band. Protoconch the same base color.

Remarks. Taxonomy. Douglassia enae is the type of the genus, exhibiting the much reduced to absent ribs in the sulcus, 2¾- to 3-whorl protoconch, angular whorls, and cup-handle-like varix within ¼-turn from the edge of the outer lip. Variability. The average total length of 29 specimens is 9.98 mm (5.0– 16.6 mm), their average W/ L ratio is 0.456. There is some variation in the shape of the last whorl, shoulder angularity and taper among the specimens examined. Also, the absence of axial ribs on the shoulder of the last whorl is a variable trait; they are present on the shoulder and extend to the suture of all whorls in some paratypes, as illustrated in Plate 61, Fig. 14. Identification. Douglassia enae is most similar to D. antillensis , new species. It differs in possessing more angular shoulders, most conspicuously on the last whorl, which in turn creates a greater taper from shoulder to end of the anterior canal. They also differ in coloration; the central band in D. enae tends to be more distinct on its adapical (posterior) margin, and protoconch the same light color of the base shell. Douglassia antillensis has an indistinct adapical margin on its central band, and a dark-colored protoconch. Although their ranges overlap, D. enae is reported from deeper water. Small specimens of D. enae may also be mistaken for Cerodrillia girardi, Lyons, 1972 . Cerodrillia girardi has broader and less angular ribs and lacks the mid-whorl color band.