Syntomodrillia harasewychi, Fallon, Phillip J., 2016

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 : 327-329

Syntomodrillia harasewychi , new species

( Plate 169 )

Drillia lissotropis auct. non Dall, 1881: is a misidentification, in part, by Dall (1889: 91, R/V Blake Sta. 273 [specimens in USNM 87477b only]),

Type material. Holotype 8.2 x 2.7 mm (USNM 1199829); 11 paratypes: 6 spec., 8.5 x 2.8, 7.9 x 2.8, 8.2 x 2.8, 7.9 x 2.8, 7.0 x 2.6 & 6.8 x 2.5 mm, type locality, M. Harasewych! May 2012 (USNM 1291371); 5 spec., 7.4 x 2.9, 8.9 x 3.2, 7.1 x 2.6, 7.5 x 2.8 & 7.0 x 3.0 mm, in bottles at 244–274 m, off Sea Aquarium, Bapor Kibra, Willemstad, Curaçao, Netherlands Antilles, 12°4'59.51"N, 68°53'56.61"W, C. Baldwin! 8 Feb 2013 (USNM 1231399).

Type locality. Off Sea Aquarium, Bapor Kibra, Willemstad, Curaçao, Netherlands Antilles, 12°04'52"N, 68°53'45"W, in glass bottles collected at 130– 168 m.

Other material examined. Two specimens, 7.5 x 2.8 & 8.3 x 2.7, in 103 fms [188 m], R/V Blake Sta. 273, near Barbados, paralectotypes of Drillia lissotropis Dall, 1881 , are this species (USNM 87477b).

Range and habitat. Netherlands Antilles ( Curaçao). Taken from 130– 274 m.

Description. Shell very small (to 8.9 mm in total length), narrowly fusiform; whorls very slightly convex, appearing cinched at the sutures, up to approximately 8¾ whorls, the last approximately 60% of total shell length; surface sculpture of opisthocline ribs. Aperture oval, narrow. Protoconch of 2–2½ smooth, translucent whorls, the first partially immersed in the second, which is well rounded. Axial sculpture of narrow opisthocline ribs with round crests that run from suture-to-suture on spire whorls, to anterior fasciole on last whorl; ribs on about first 2 teleoconch whorls appear only below periphery, and are almost nodulose; ribs number 10–13 on penultimate and 8–12 on last whorl to varix. Intercostal space varies from less than to at least equal to rib width. Ribs widest on whorl periphery, narrow anteriorly and on shoulder where they are little changed, only slightly recurved. Varix larger and wider than preceding ribs, about ⅓-turn from edge of outer lip. Spiral sculpture of fine grooves or threads visible between ribs on about the anterior ⅔ of the whorl (absent in sulcal area); threads on anterior fasciole. Sulcus absent; former positions of anal sinus represented by recurved ribs and by absence of spiral grooves on whorl shoulders of the last 2 whorls. Outer lip thin, outer portion of lip broken on holotype and on all paratypes, as all are from an octopus midden. Anal sinus not complete on specimens examined. Inner lip recumbent, but detached, moderately wide, widest along columella, pinched up on anterior portion of columella; formed into a weak callus posteriorly at its junction with the outer lip. Anterior canal moderately long, straight except for a slight curve to the right at its end when viewed ventrally; unnotched; columella straight; fasciole not swollen. Color uniformly white to off white with a golden brown patch on shoulder and ventral side of the varix.

Remarks. Taxonomy. Syntomodrillia harasewychi is characterized by a narrow glossy shell with a moderately long anterior canal, axial ribs that extend suture-to-suture, spiral grooves or threads in intercostal space, and a varix that is not hump-like positioned about ⅓-turn from the edge of the outer lip. The relatively flat whorls are unique. Variability. The average total length of 10 specimens (two with a missing apex excluded) is 7.86 mm (7.0– 8.9 mm) and an average W/ L ratio of 0.357. Identification. Syntomodrillia harasewychi is very similar to S. woodringi Bartsch, 1934 , and similar to S. portoricana , new name, S. hesperia , new species, S. cookei (E.A. Smith, 1888) , and S. carolinae Bartsch, 1934 . It has a straighter whorl profile than S. woodringi . From S. portoricana it differs in the shape of the protoconch, in possessing narrower ribs with round crests, not broad ribs with ridged crests, and is white, not golden brown. From S. hesperia it differs in the shape of the protoconch, in possessing a less tapered last whorl, an unnotched anterior canal, and is white, not golden brown. From S. cookei it differs in being less translucent, in possessing a straighter anterior canal and ribs, and stronger intercostal threads. From S. carolinae it differs in having less convex whorls, and in possessing spiral threads or grooves on most whorls, not just the last.

Etymology. Harasewych’s Syntomodrillia , named in honor of Dr. M.G. Harasewych, organizer of the Smithsonian’s Deep Reef Observation Program operating from the Curaçao Seaquarium, collector of the first specimens of this species and of several others new to science presented in this work.

Figures

PLATE 169. Syntomodrillia harasewychi. Upper panel. Figs. 1 – 2: holotype off Sea Aquarium, Curaçao, Netherlands Antilles (USNM 1199829). Fig. 1: ventral, lateral, and dorsal views; Fig. 2: enlarged view of protoconch (not to scale). Lower panel, paratypes. Figs. 3 – 10: paratypes, off Sea Aquarium, Curaçao, Netherlands Antilles. Figs. 3, 6 – 8: USNM 1291371; Figs. 4 – 5: USNM 1231399; Figs. 9 – 10: paralectotypes of Drillia lissotropis Dall, 1881 from near Barbados that are this species (USNM 87477 b).