Clathrodrillia tryoni (Dall, 1889)

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 : 107-108

Clathrodrillia tryoni (Dall, 1889)

( Plate 48 )

Drillia tryonii Dall, 1889a: 83 [also spelled “ tryoni ”].

Drillia tryoni [sic] Dall, 1889: Sander & Lalli (1982: 317).

“ Crassispira ” tryoni [sic] (Dall, 1889): Kaicher (1984: card 3927 [photo of USNM 87449, the lectotype]). Clathrodrillia tryonii (Dall, 1889) : Williams (2005 species 1546, 1547 [L photo pair only]).

Not this species or unverified extralimital reports.

Clathrodrillia tryonii (Dall, 1889) : Williams (2005; 2009: species 1546 [R photo pair only = Calliclava sp.]); Daccarett & Bossio (2011: 129, fig. 787 [= Calliclava sp.]).

Type material. The 12.6 x 4.7 mm specimen from near Grenada (USNM 87449) is in best condition and is here designated as lectotype. There are 3 known paralectotypes: 1 spec., 10.9 x 4.1 mm, R/V Blake Sta. 262 near Grenada in 92 fms [168 m] (MCZ 7056); 1 spec., 11.4 x 4.4 mm, in 76–100 fms [139–183 m], R/V Blake Sta. 272 near Barbados (MCZ 7057); and 1 spec., 10.6 x 4.0 mm, in 95 fms [174 m], R/V Blake Sta. 231 near St. Vincent (MCZ 7055).

Type locality. R/V Blake Sta. 262 near Grenada, 12°01′45″N, 61°47′25″W, in 92 fms [168 m].

Other material examined. An additional 13 specimens were examined: 1 spec., 8.6 x 3.1 mm, in 80 m, Port- Louis, Grand Cul-de-Sac Marin, Guadeloupe KARUBENTHOS 2012 Sta. GD23, 16°25.0'N, 61°32.8'W, 14 May 2012 (MNHN IM-2013-20797) was sequenced and has the following barcode accession numbers:

1 spec., 8.6 x 3.3 mm (juv.), in 146 m, off Barbados (USNM 900049); 1 spec., 11.3 x 4.1 mm, in 137–146 m, off Lazaretto, Barbados, J.B. Henderson, Jr., SUI (State University of Iowa) Expedition of 1918 Sta. 85 (USNM 502548); 1 spec., 10.3 x 3.7 mm, in 137–146 m, off Payne’s Bay Church, Barbados, J.B. Henderson, Jr., SUI Expedition of 1918 Sta. 41 (USNM 502554); 1 spec., 10.2 x 3.7 mm, in 60 m, off Pelican I., Barbados, J.B. Henderson, Jr., SUI Expedition of 1918 Sta. 51 (USNM 502551); 3 spec., 9.9 x 3.6, 11.9 x 4.3 & 12.9 x 4.5 mm, in 155–174 m, off Holetown, St. James, Barbados (13°10'52''N, 059°38'30''W) F. Sander! (ANSP 353516); 1 spec., 13.5 x 4.8 mm, in 155–174 m, off Holetown, St. James, Barbados (13°10'52''N, 059°38'30''W) F. Sander! (ANSP 353517); 1 spec., 7.6 x 2.8 mm, in 155–174 m, off Holetown, St. James, Barbados (13°10'52''N, 059°38'30''W) F. Sander! (ANSP 353518); 3 spec., 13.6 x 4.7, 11.8 x 4.3 & 10.6 x 4.1 mm, in 183 m, off St. James, Barbados, F. Sander! 1978 (UF 470286).

Range and habitat. Guadeloupe; SVG (near St. Vincent); Barbados; Grenada. Dall believed this to be a shallow water species, that specimens were adventitious in deep water samples (139–183 m) from the R/V Blake offshore of St. Vincent, Barbados and Grenada localities on account of their “injured” condition. However Sander & Lalli (1982: 317) report live specimens from 155–174 m depths off Holetown, St. James, Barbados (Pl. 48, Figs. 7–8), and some specimens taken from off Barbados during the SUI Expedition of 1918 in 60–146 m appear to have been fresh-taken (Pl. 48, Figs. 12–13). The specimen from Grand Cul-de-Sac Marin, Guadeloupe, was live-taken at 80 m and its tissue processed for molecular analysis. Data from fresh specimens suggests their habitat as moderately deep water (60–183 m), not shallow water as surmised by Dall.

Description. Shell small (to 13.6 mm), narrowly fusiform, translucent between sculptural elements, to approximately 10 slightly convex (early teleoconch) to straight-sided turreted whorls, the last whorl approximately 57% of total length. Sculptural elements of axial cords and spiral threads; aperture narrow. Protoconch glossysmooth, translucent, of approximately 1¾–2 rounded whorls, the first partially immersed in the second such that the apex appears blunt. Axial sculpture of straight, narrow ribs that stretch from suture-to-suture on the spire whorls, and evanesce on shell base, their width about the same as the interspaces; approximately 17–20 on penultimate, and 7–14 to varix on last whorl. Ribs are reduced abruptly at sulcus producing a right-angled shoulder, then continue to suture much reduced and curved, reflecting the trace of the anal sinus. Fine axial folds are present on the outer lip. Varix narrow, protruding, positioned about ⅓-turn from the edge of the outer lip. Spiral sculpture of evenly spaced heavy spiral threads, roughened by growth striae, spaced 2–4 times their width that override ribs producing a beaded effect on rib crests, and the shell surface a reticulate appearance. Sulcus strongly demarcated by abruptly reduced ribs at its edge, producing a right-angled shoulder; about 5 spiral threads present; growth striae tend to become lamellate. Outer lip thin, flattened from the varix to lip edge, which is bent inward posteriorly; no evidence of a stromboid notch in examined specimens. Edge of lip smooth, forms a flattened arc from anal sinus to anterior canal; without teeth or scalloping. Anal sinus U-shaped with a round apex, slightly offset from the shell’s axis by the parietal callus and inflection of the outer lip below it. Inner edge of sinus flared, such that it appears spout-like. Inner lip emarginated, thick, wide, erect anteriorly; parietal callus present at its posterior end. Anterior canal moderately long, shallow, open, unnotched. Anterior fasciole not swollen; with spiral cords. Color white; some with a golden-brown patch on shoulder of varix.

Remarks. Nomenclature. Dall spelled the minor epithet with and without the second “i” in the original species description (Dall, 1889a: 83). As First Revisor (ICZN 2000 Article 24.2.3) the spelling “ tryoni ”, with a single ending “i”, is herein fixed as the correct spelling. Taxonomy. Clathrodrillia tryoni was described without illustration. A photograph of a type specimen was not published until much later—in Kaicher (1984: card 3927). The protoconch, which was not described by Dall, is missing from all of the types and resulted in some confusion between this and species of Calliclava that have a distinctively carinate one. Intact specimens of C. tryoni have a protoconch of about 2 glossy-smooth whorls (Pl. 48, Fig. 2). Clathrodrillia tryoni is typical for the genus in possessing numerous ribs and heavy spiral elements, a somewhat spout-like anal sinus, and heavy varix. Variability. The average length of 17 specimens is 10.96 mm (7.6–13.6 mm); their average W/ L ratio is 0.367. The examined shells appear fairly uniform in most other respects. Identification. Clathrodrillia tryoni has been confused with Calliclava spp. because of their similarity in size and shell sculpture. The latter is easily distinguished by its carinate protoconch, presence of spiral threads between ribs, not overriding them as in C. tryoni , therefore a smooth not coarse feel, and sometimes more colorful shell. Only white specimens of C. tryoni have been observed, some with a golden-brown color patch on the shoulder of the varix. Clathrodrillia tryoni is very similar to C. wolfei (Tippett, 1995) but differs in having more ribs (17–20 versus 8–10 on the penultimate whorl).

Figures

PLATE 48. Clathrodrillia tryoni (Dall, 1889). Upper panel. Fig. 1: lectotype from near Grenada (USNM 87449): ventral. lateral & dorsal views; Fig. 2: enlarged views of protoconch of specimen in Fig. 12 (not to scale); Fig. 3: apical view of specimen in Fig. 9, V = varix, L = edge of outer lip. Lower panel. Figs. 4 – 6: paralectotypes. Fig. 4: near Grenada (MCZ 7056); Fig. 5: near Barbados (MCZ 7057); Fig. 6: near St. Vincent (MCZ 7055); Figs. 7, 9 – 10: off Holetown, St. James, Barbados (ANSP 353516); Fig. 8: off Holetown, St. James, Barbados (ANSP 353517); Fig. 11: off St. James, Barbados (UF 470286); Fig. 12: off Lazaretto, Barbados (USNM 502548); Fig. 13: off Pelican I., Barbados (USNM 502551); Fig. 14: off Payne's Bay Church, Barbados (USNM 502554); Fig. 15: Grand Cul-de-Sac Marin, Guadeloupe (MNHN IM- 2013 - 20797).