Splendrillia bartschi (Haas, 1941) Haas, 1941

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 : 287

Splendrillia bartschi (Haas, 1941) , new combination

( Plate 146 )

Cymatosyrinx bartschi Haas, 1941: 172 , pl. 2, figs. h, i. Powell (1966: 90); Abbott (1974: 276); Jensen & Pearce (2009: 173). Drillia interpunctata auct. non (E.A. Smith, 1882): Peile (1926: 84).

Splendrillia coccinata auct. non (Reeve, 1845): is likely a misidentification by Jensen & Pearce (2009: 173).

Type material. Holotype 10.5 x 4.0 mm (FMNH 13672). T.H. Bean!, 13 Oct 1905. Only a photograph was examined, which is courtesy of Mr. Jochen Gerber of the FMNH.

Type locality. Argus Bank, Bermuda Is., in 30 fms [55 m] depth.

Material examined. A total of 4 specimens were examined: 3 spec., 12.2 x 4.8, ex H.G. Lee coll. (USNM 1291357), 10.9 x 4.1, & 9.6 x 3.9 mm (H.G. Lee coll.), in 11–12 m, North Rock, Bermuda, A.T. Guest & J.R.M. Lightbourn! 1976; 1 spec. 2.9 x 1.6 mm, in 100 m, 6 mi [9.7 km] N of boat yards, Somerset Pt., Bermuda, R. Jensen & J.R.M. Lightbourn! May 1994 (H.G. Lee coll.).

Range and habitat. Known only from Bermuda. Dredged from 11– 100 m. This species (as Cymatosyrinx bartschi Haas, 1941 ) is listed as endemic to Bermuda by Jensen & Pearce (2009).

Description. Shell small (to 12.2 mm in total length), glossy-smooth, fusiform, truncated anteriorly, with 8 or perhaps a few more convex whorls, the last approximately 61% of the total length. Predominant sculptural element of axial ribs; aperture wide, anterior canal very short. Protoconch of approximately 1¾–2 smooth round whorls; tip immersed such that the first whorl is at an angle above the horizontal. Axial sculpture of narrow opisthocline ribs that run from the sulcus to suture on spire whorls, and evanesce just below whorl periphery on last whorl. Ribs number 12–15 on penultimate, 7–11 on last whorl to varix, and are wider than their intercostal spaces. Growth striae very fine, strongest near end of last whorl, on outer lip. Varix hump-like, approximately ¼-turn from the edge of the outer lip. Spiral sculpture absent except for faint threads on shell base near anterior fasciole; stronger on anterior fasciole. Sulcus concave, without ornamentation except for an occasional rib trace to the suture; about ⅓- height of spire whorls. Outer lip flattened from varix to lip edge, which forms a low arc from anal sinus to slightly beyond and out from the tip of anterior canal (ear-like); only a slight indentation in place of a stromboid notch; thickened along its edge. Anal sinus a deep notch, its apex adjoining suture behind parietal lobe. Inner lip narrow, thin, unemarginate; formed into a weak parietal lobe posteriorly. Anterior canal open, very short but distinctly demarcated from aperture, end of canal notched; fasciole not swollen. Color white to light pink with a broad, light pink to deep-rose band from the whorl periphery to the shell’s anterior; band reduced to spots or lines between ribs.

Remarks. Nomenclature. The type specimen was tentatively placed in Cymatosyrinx Dall, 1889 by Haas who remarked that the material (presumably the single type specimen) was too poor to be certain of its [generic] placement. Dall did not formally describe Cymatosyrinx but did designate a type ( Pleurotoma lunata Lea, 1843 ) from which subsequent workers developed a description (Fargo, 1954 and Powell, 1966). Powell (1966: 90) described Cymatosyrinx as having, among other characteristics, a polished surface, protoconch with a carinate second whorl, subsutural fold made nodulose at axial rib intersections, axial ribs extending to the anterior fasciole, ridge-margined inner lip, and deeply notched anterior canal. Taxonomy. Haas’ description and illustration of S. bartschi is more consistent with those of Splendrillia , including a smooth protoconch without a carinate second whorl, no subsutural fold, an anal sulcus without sculptural elements, axial ribs that fade on the shell base, and no ridge on the inner lip. Furthermore, although not described by Haas, the anal sinus of S. bartschi is typical of Splendrillia— its apex adjoins the suture behind the parietal lobe (its entrance offset from the suture by the parietal lobe). Variability. The three mature specimens examined have an average length of 10.90 mm (9.6–12.2 mm) and average W/ L ratio of 0.390. Their color varies from white to a light pink with a broad, deep-rose band from the whorl periphery to the shell base. It may also be a “vinaceous cinnamon” color, the color description employed by Haas for the holotype. Identification. Splendrillia bartschi is unique among Splendrillia in having a well-rounded somewhat globose body whorl. It is close in size to S. bahamasensis , new species but the latter has broader, straighter, and more angular, and fewer axial ribs. Splendrillia bartschi differs from S. interpunctata (E.A. Smith, 1822) principally in having much less angular shoulders and a more globose last whorl. From S. cruzensis , new species, it differs in being stouter, in having a more globose last whorl, and less angular shoulders.

Figures

PLATE 146. Splendrillia bartschi (Haas, 1941). Upper panel. Fig. 1: holotype, Argus Bank, Bermuda (FMNH 13672). Photograph courtesy of Mr. Jochen Gerber of the FMNH; color not true. Figs. 2 – 3: specimens from near North Rock, Bermuda (H. G. Lee coll.). Lower panel. Figs. 4, 6: specimen from near North Rock, Bermuda (USNM 1291357). Fig. 4: ventral, lateral & dorsal views; Fig. 6: apical view, V = varix, L = edge of outer lip. Fig. 5: enlarged view of the juvenile with a better view of the protoconch (not to scale), Somerset Pt.: 9.7 km N of boatyards (H. G. Lee coll.).