Splendrillia coccinata (Reeve, 1845)

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 : 289-292

Splendrillia coccinata (Reeve, 1845) , neotype designation

( Plate 147 )

Pleurotoma coccinata Reeve, 1845 a: pl. 33, fig. 299: Reeve (1846b: 118); Paetel (1888: 60 [list]).

Drillia (Clavus) coccinata (Reeve, 1845) : Tryon (1884: 188 [in part], pl. 13, fig. 54 [=Reeve’s drawing]; not pl. 30, fig. 85 [= Drillia laevisulcata von Maltzan, 1883 of western Africa].

Drillia coccinata (Reeve, 1845) : H. & A. Adams (1853: 90 [list]).

Pleurotoma (Drillia) coccinatum (Reeve, 1845) : Weinkauff & Kobelt (1887: 212, pl. 40, fig. 9 [=Reeve’s drawing]).

Not this species or unconfirmed extralimital reports.

Pleurotoma coccinata Reeve, 1845 : Krebs (1864: 8; 1866: 397 [ U.S. Virgin Is.; St. Bart; St. Martin; Anguilla; Saba]); Arango y Molina (1878: 218 [ Cuba]); Mørch (1878: 13).

Drillia coccinata (Reeve, 1845) : Dall (1889a: 90 [St. Croix; Barbados; Dominican Republic]); Nowell-Usticke (1959: 81 [St. Croix; = Splendrillia cruzensis , new species]);Warmke & Abbott (1961: 135, pl. 25, fig. h [ Puerto Rico & Virgin Is. = Fenimorea fucata (?)]); Vokes & Vokes (1984: 30, 58, pl. 21, fig. 2 [= Fenimorea chaaci (Espinosa & Rolán, 1995) ]); Espinosa et al. (1995: 41 [ Cuba]).

Splendrillia coccinata (Reeve, 1845) : Rios (1983 [ Brazil]); Rios (1985: 139, pl. 47, fig. 642 [ Brazil]); Absalão et al. (2005: 25, fig. 24 [= Cerodrillia sp.]); Williams (2005, 2006, 2009: species 1582 [left photo = S. cruzensis ; right photo =undescribed species]); Rios (2009: 315, No. 804 [ Brazil]); Jensen & Pearce (2009: 177 [= Splendrillia bartschi (Haas, 1941) ]).

Cerodrillia coccinata (Reeve, 1845) : Jong & Coomans (1988: 111); Díaz (1994: 40 [ Colombia]); Díaz & Puyana (1994: 225, pl. 67, fig. 890); Rios (2009: 310, No. 783 [Bahia to Rio de Janeiro, Brazil; photo is from Williams, 2009 who does not give the specimen’s locality]); Daccarett & Bossio (2011: 129, fig. 781 [ Colombia]).

Splendrillia (Syntomodrillia) coccinata (Reeve, 1845) : Rios (1994: 163, pl. 54, fig. 734 [ Brazil]).

Type material. Not located; presumed lost. Reeve’s drawing in Conchologia Iconica 1 (Reeve, 1845a: pl. 33, fig. 299) is here used as a representation of the type.

Neotype designation. In general accordance with the requirements for the designation of a neotype specified in ICZN 2000 Article 75.3, and described next, the specimen illustrated in Pl. 147, Figs. 2 –3 and deposited in USNM 12191358 is here designated as the neotype. Need for clarification. As shown in this work, there are other taxa that are similar to S. coccinata , some of which have been misidentified as S. coccinata in the literature (see under “Not this species” above), probably as a result of the scanty description by Reeve:

“Shell ovate, acuminated towards the apex, whorls smooth, concave round the upper part, plicately nodose beneath; base truncated; white, stained with rose-scarlet on the back and between the nodules.”

Taxonomists were probably fixed on Reeve’s detailed description of its color in a mistaken belief that it was unique. The detailed color description contrasts his otherwise general description of the shell. The color pattern, white with rose or scarlet, is found not only in other Splendrillia , but also within the Bellaspira genus. Consequently, more descriptive information of the morphology is necessary to separate similar species, detail that can only be gotten from a type specimen. It is for these reasons that a neotype is necessary to anchor the taxon’s identity and reduce confusion in the future. S. coccinata is believed to be part of a wide-ranging complex of closely related species and molecular fingerprinting may be necessary to support their separation at the species level. Since the proposed neotype originates from and is fairly abundant in a well-defined small geographic area (Chatham Bay, Union I.) specimens from the same population can be acquired for future barcode analysis. Characters differentiating species-group taxon. S. coccinata bears all the characteristics of the genus (see introduction to Splendrillia ). The proposed neotype is described below under “Description”. Generally, of the known species of Splendrillia , S. coccinata is the smallest (<10 mm), with numerous close-set, slightly opisthocline ribs and angular shoulders. Both Splendrillia subtilis , new species, and Splendrillia stellae , new species are also <10 mm, but both have fewer and broader ribs with round, not angular shoulders. The color described by Reeve is not uniform—the same population may include individuals ranging from all-white to tan with brownish orange streaks. Recognition of the neotype. The drawing in an original copy of Iconica measured 25.5 mm in length and as stated in the caption is three times its natural size; the original specimen is therefore estimated to be about 8.5 mm (8 mm in Weinkauff & Kobelt, 1887: 212, by their reckoning, and 8.3 x 3.7 mm according to Jong & Coomans, 1988: 111). The proposed neotype is shown at about the same scale next to a photograph of Reeve’s drawing in the inset in Pl. 147, Fig. 2. It is shorter (7.8 versus 8.5 mm) than Reeve’s original, but otherwise a good match. It is close in color pattern and form to Reeve’s drawing. Search effort. Reeve’s types are housed at the NHMUK where search efforts were undertaken. According to museum personnel, Ms. Kathie Way originally, and then again a few years later on a visit of 9–10 June 2010 Ms. Amelia MacLellan, could not locate the type. Inquiry was made again later of subsequent curators: Ms. Natalina Bonassera reported on 20 July 2010 that the specimen was not in the type material or the general collection; Ms. Andreia Salvador reported similarly on 16 Dec 2013 that the type could not be located. Other major European museums included MNHN (Dr. Yuri Kantor, pers. comm. 17 May 2011); and again at the same institution, Dr. Peter Stahlschmidt ( Pers. comm. 8 Nov 2011), both of whom, though not museum staff, kindly searched at my request but were unable to locate the type. Finally, at the MHNG (Dr. Yves Finet, pers. comm. 30 Mar 2011) searched. All reported it not in that institution’s collection. Characters differentiating the nominal taxon. Only a single taxon is recognized within the species-group, so the distinguishing characteristics are the same as for S. coccinata . Original type locality. Reeve did not report a locality for the type. The range of the proposed neotype is presently known to be SVG and Grenada. Reeve has reported several of his specimens in Iconica from St. Vincent, so it is possible that his specimen of P. c o cc i na t a originated from the same area. According to Tryon (1884: 188), "West Indies". The earliest report of this species in the western Atlantic was probably by Krebs (1864: 8): St. Thomas, St. John, St. Barts, St. Martin, and Anguilla. These early reports may have actually been of Splendrillia interpunctata (E.A. Smith, 1882) , which is within that species’ known range (described later in this paper and of course not yet described in Krebs’ time) but also rose-colored. It is not known how Tryon arrived at “West Indies” for this species’ range, except perhaps basing his finding on the inclusion of the taxon on Krebs’ list. Repository of the neotype. The proposed neotype will be deposited and available for study at the USNM. Its catalog number is USNM 1291358. Furthermore, specimens of the same taxon have been distributed to a number of museums, which are noted in the list of examined material.

Type locality. Original type locality unknown; the proposed neotype is from Chatham Bay, Union I., St. Vincent and the Grenadines, at 20 m.

Material examined. A total of 47 specimens were examined. St. Vincent & the Grenadines: 12 spec., 7.8 x 3.2 (neotype, USNM 1291358), 7.8 x 3.0, 8.1 x 3.3, 8.1 x 3.2, 8.7 x 3.5 & 8.4 x 3.6 mm (USNM 1291359), 8.1 x 3.4, 7.5 x 2.9, 8.0 x 3.0, 7.9 x 3.2, 7.5 x 3.2, 7.6 x 3.1 mm (ANSP 464958) in 20 m, Chatham Bay, Union I., G. Mackintosh!, 6 Apr 2007; 4 spec., 9.2 x 3.6 (USNM 1291360), 8.9 x 3.4, 9.1 x 3.3, & 7.7 x 3.1 mm (M. Williams coll.), in 12 m, S end of Baliceaux I., G. Mackintosh!, 23 Apr 1997. Grenadian Is.: 2 spec., 8.1 x 3.3 and 7.8 x 3.0 mm, in 11 m, Saline I., G. Mackintosh! 1 Feb 1997 (UF 470343); 6 spec., 6.8 x 2.8, 7.0 x 2.8, 6.8 x 2.6, 6.8 x 2.7, 6.6 x 2.7 & 8.0 x 3.0 mm, in 15 m, Ronde I., G. Mackintosh!, 25 Jan 1997 (MZSP 122072); 1 spec., 9.7 x 3.6 mm, in 6 m, Ronde I., G. Mackintosh!, 5 Jun 1998 (M. Williams coll.); 1 spec., 6.9 x 3.1 mm (incomplete length), in 11 m, Large I., G. Mackintosh!, 30 Nov 1996 (M. Williams coll.); 1 spec., 7.6 x 3.1 mm, in 11 m, Large I., G. Mackintosh!, 27 Jan 1997 (MZSP 122073); 1 spec. 8.0 x 3.4 mm (apex broken), in 7 m, Glover I., G. Mackintosh!, 12 Jun 2003 (author’s coll.); 1 spec. 6.9 x 3.1 mm (apex broken), in 11 m, Glover I., G. Mackintosh! 30 Nov 1996 (M. Williams coll.). Grenada: 1 spec., 7.4 x 3.0 mm, in 9 m, Canoe Bay, G. Mackintosh! 20 Sep 1996 (M. Williams coll.); 2 spec., 7.7 x 3.1 & 7.0 x 2.7 mm, in 9 m, Canoe Bay, G. Mackintosh! 9 Aug 1996 (MZSP 122074); 13 spec., 8.1 x 3.2 mm (P. Shahlschmidt coll.), 8.0 x 3.1, 8.0 x 3.3, 7.8 x 3.1, 8.2 x 3.3, 7.2 x 2.9 mm (UF 496646), 7.5 x 3.0, 7.9 x 3.2, 8.2 x 3.2, 8.1 x 3.3, & 7.4 x 3.0 mm (DMNH 240359), in 22 ft, outside anchorage, St. Georges, G. Mackintosh! 24 Jun 2003; 2 spec., 7.3 x 3.0 & 8.3 x 3.3 mm, in 9 m, Flamand Bay, G. Mackintosh! 24 Aug 2003 (BMSM 14997); 1 spec., 8.0 x 3.4 mm, in 10 m, Devil’s Bay, G. Mackintosh! 14 Sep 1996 (BMSM 14996).

Range. SVG (Baliceaux I.; Union I.) and Grenada (Saline I.; Ronde I.; Large I.; Glover I.; Grenada I.). Reported from 6– 20 m.

Description. A fully mature shell from Chatham Bay, Union I., SVG, has been selected as the neotype because it closely resembles Reeve’s drawing. Shell is small, 7.8 x 3.2 mm (other specimens to 9.7 mm), 7 whorls, fusiform, truncated anteriorly; body whorl approximately 60% of overall height; glossy and somewhat translucent. Excavated sulcus and nodule-like ribs on the spire whorls give the shell a turreted outline. Protoconch paucispiral, of approximately 2 smooth, round whorls. Axial sculpture of oblique ribs terminating at sulcus, continue as arcuate, thread-like traces in the sulcus; rib crests ridged near shoulder, round below periphery, evanescing on lower shell base. Ribs number 10–13 on penultimate, 9–11 on body whorl to varix, wider than their interspaces. Growth striae present over entire shell, very fine on spire whorls, strongest on body whorl, especially on outer lip. Spiral sculpture of ridge-like grooves on shell base, becoming coarser on anterior fasciole. Shell surface microsculpture as seen with the dissecting microscope consists very fine spiral lines. As seen in SEM images, the spiral lines resolve into rows of joined punctae (see Pl. 140, Figs. 3–4), between which are rows of more widely spaced punctae. Sulcus broad, slightly concave at shoulder, ⅓–½ the height of the spire whorls, with ribs absent or reduced to narrow arcuate lines within, sometimes appearing as small nodes at the suture where it overrides the previous whorl’s ribs. Varix dominant, hump-like, and positioned about ⅓-turn from the edge of the outer lip. Outer lip smooth, without ribs but thickened in older specimens, somewhat flattened from the varix to its edge; edge of lip traces a low arc from the anal sinus to end of anterior canal; only a slight indentation, rather than a true stromboid notch present anteriorly. Anal sinus a deep notch near suture, apex of sinus adjoins suture behind parietal lobe, which may slightly constrict entrance. Inner lip is very thin, not margined except at its anterior end where it is erect. Anterior canal distinct but short, notched and bent slightly to the left at its end when viewed ventrally. Color white with 3 broad pink bands, on shoulder, mid-body, and anteriorly; dark rose on dorsum, on varical hump, and streaks between ribs. Color varies in other specimens from light pink, to tan or white with brownish-orange streaks between ribs or on varix, to all white.

Remarks. Taxonomy. Splendrillia coccinata has all of the characteristics of the genus: a glossy shell with a bare sulcus; anal sinus adjoining the suture behind the parietal lobe, a hump-like varix positioned about ⅓-turn from the edge of the outer lip, and microsculpture absent on shell surface. Spiral threads are present on the anterior fasciole. Variability. The average length of 48 unbroken specimens is 7.88 mm (range 6.6–10.0) and their mean W/ L ratio is 0.402. Identification. Splendrillia coccinata is most similar to S. cruzensis , new species but differs in being smaller (7.88 versus 11.96 mm average total length), in possessing more angular shoulders, and finer growth striae. The coarse growth striae imparts a dull finish on S. cruzensis . From S. karukeraensis , new species it differs in being smaller (7.88 versus 11.80 mm average total length), and a more rounded last whorl, not tapered as in S. coccinata . From S. interpunctata (E.A. Smith, 1882) in being smaller (7.88 versus 10.24 mm average total length), has more angular shoulders, and more crowded, less robust ribs. From S. bahamasensis , new species it differs principally in being smaller (7.88 versus 12.24 mm average total length), and in having more numerous and more oblique axial ribs (10–13 versus 6–10 on the penultimate whorl). Growth striae are more prominent on S. bahamasensis , than on S. coccinata imparting a dull finish to its shell surface. Populations of all of the aforementioned species, except S. karukeraensis are believed to have a high frequency of forms with rose and carmine color.

Figures

PLATE 147. Splendrillia coccinata (Reeve, 1845). Upper panel. Fig. 1: Pleurotoma coccinata Reeve, copy of Reeve’s pl. 33, fig. 299; Fig. 2: neotype, dorsal view at the same scale for comparison; Fig. 3: neotype, Chatham Bay, Union I., SVG (USNM 1291358): ventral, lateral & dorsal views. Lower panel. Figs. 4 – 7: Chatham Bay, Union I., SVG: Figs. 4, 6: USNM 1291359; Figs. 5, 7: ANSP 464958; Fig. 8, 10: Flamand Bay, Grenada (BMSM 14997); Fig. 9: Devil’s Bay, Grenada (BMSM 14997); Fig. 11: Canoe Bay, Grenada (MZSP 122074); Fig. 12: St. Georges, Grenada (UF 496646); Figs. 13 – 17: Chatham Bay, Union I., SVG: Fig. 13: USNM 1291359; Figs. 14 – 17: ANSP 464958; Fig. 18: St. Georges, Grenada (DMNH 240359); Fig. 19: Large I., Grenada (MZSP 122073); Figs. 20 – 21: S end of Baliceaux I., SVG: Fig. 20: M. Williams coll.; Fig. 21: USNM 1291360; Figs. 22 – 23: Saline I., Grenada (UF 470343); Fig. 24: Ronde I., Grenada (MZSP 122072); Figs. 25 – 27: St. Georges, Grenada: Figs. 25 – 26: UF 496646; Fig. 27: P. Stahlschmidt coll.