Fenimorea caysalensis Fallon, 2016, new species
Creators: name: Fallon, Phillip J.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Drilliidae
Fenimorea
Fenimorea caysalensis

description: Fenimorea caysalensis, new species
(Plates 69, 70)
Type material. Holotype 11.8 x 5.0 mm (USNM 1291343); 33 paratypes from the type locality: 4 spec., 11.9 x 5.5, 12.0 x 5.3, 12.5 x 5.3 & 12.5 x 5.3 mm (USNM 1291344); 4 spec., 11.7 x 5.0, 11.1 x 5.4, 11.1 x 4.8 & 11.2 x 5.2 mm (ANSP 464989); 4 spec., 11.3 x 5.1, 11.6 x 5.0, 11.6 x 5.4 & 11.2 x 5.0 mm (BMSM 14989); 4 spec., 9.4 x 4.5, 10.x 4.6, 10.0 x 4.4 & 10.0 x 4.6 mm (DMNH 240357); 4 spec., 10.2 x 4.6, 9.2 x 4.4, 10.0 x 4.6 & 10.2 x 4.6 mm (UF 496638); 13 spec., 10.9 x 4.8, 10.4 x 4.7, 10.3 x 4.4, 10.1 x 4.6, 10.6 x 4.7, 10.8 x 4.9, 10.5 x 4.6, 10.7 x 4.7, 10.8 x 4.7, 10.9 x 4.8, 11.0 x 4.9, 12.1 x 5.3 & 12.4 x 5.1 mm (author’s coll.). All types G. Mackintosh! 22–23 Feb 1996.
Type locality. W side of Dog Rocks, Cay Sal Bank, Bahama Is., in 10 m.
Other material examined. An additional 93 specimens were examined: 1 spec., 9.7 x 4.5 mm, in 9 m, Pickles Reef, 5 mi [8 km] ESE of Tavernier Creek, E end of Plantation Key, Florida Keys, H.G. Lee! 9 Jul 1989 (UF 470298); 63 spec., 8.2–12.0 mm, 19 measured: 11.4 x 4.8, 12.3 x 4.9, 11.1 x 4.7, 11.7 x 5.0, 10.1 x 4.4, 8.2 x 3.8, 10.5 x 4.2, 9.4 x 4.4, 12.0 x 4.8, 10.3 x 4.6, 10.3 x 4.3, 9.8 x 4.5, 11.5 x 4.7, 11.8 x 4.8, 10.8 x 4.6, 12.0 x 5.0, 9.3 x 4.3, 9.3 x 4.3 & 10.8 x 4.6 mm, in 3 m, Honeymoon Cove, Gun Cay, Bimini Is., Bahama Is., G. Mackintosh! 8 Apr 1994 (author’s coll.); 1 spec., 11.1 x 4.4 mm, N Cat Cay, Bimini Is., B. Holliman! 25 Oct 1987 (UF 470297); 26 spec., 9.8 x 4.3, 9.5 x 4.2, 9.1 x 4.3, 9.6 x 4.6, 8.9 x 4.4, 8.9 x 4.1, 8.8 x 4.1, 10.2 x 4.7, 10.1 x 5.0, 8.8 x 4.2, 9.2 x 4.4, 8.9 x 4.3, 10 x 4.5, 9.3 x 4.6, 9.7 x 4.6, 9.8 x 4.6, 9.0 x 4.2, 10.2 x 4.6, 10.7 x 4.9, 9.1 x 4.2, 8.5 x 4.0, 9.0 x 4.4, 8.8 x 4.4, 9.5 x 4.8, 9.2 x 4.2 & 10.6 x 4.5 mm, in 9 m, Cay Sal, Cay Sal Bank, Bahama Is., G. Mackintosh! 22 Apr 1994 (author’s coll.); 2 spec., 10.1 x 4.2 & 10.8 x 4.6 mm, in 1.2 m, W side of Saddle Cay, N Exuma Cays, Bahama Is., G. Duffy! 5 Sep 1977 (UF 470317).
Range and habitat. Florida Keys (Plantation Key); Bahama Is. (Dog Rocks & Cay Sal, Cay Sal Bank; Gun Cay, N Cat Cay, Bimini Is.; Exuma). It has been reported from 3– 10 m.
Description. Shell small, to 14.7 mm in total length, stoutly fusiform, almost half as wide as long; of up to 9 straight-sided whorls with an acuminate spire tip, and with only slight indentations marking suture and anterior boundary of the sulcus. Last whorl 67% of shell length. Protoconch smooth, of approximately 2 round whorls; transition to teleoconch difficult to discern because of pitted surface on account of slight erosion. Axial sculpture of low irregular ribs, some extend from suture-to-suture a few end at sulcus, some slightly nodulose at whorl periphery, others are very low, almost obsolete; arcuate and slightly reduced in sulcus, some slightly nodulose; evanesce below periphery of body whorl; 12–18 on penultimate whorl, 8–13 on last whorl to varix. Vari x humplike, about ⅓-turn back from the edge of the outer lip. Spiral sculpture of closely spaced microscopic incised lines over the shell surface, more widely spaced on the shell base, cut by closely spaced growth striae that form microscopic pits between. Deeper, more widely spaced spiral grooves override this pattern. Sulcus demarcated by a crease on the shell surface. Outer lip thin, lightly scalloped by projections of the deeper, more widely spaced spirals on thin-lipped specimens to smooth on thick-lipped specimens; a slight inward fold present on edge on the anterior portion of lip. Outer lip surface from varix to lip’s edge strengthened by up to 5 irregular axial folds in mature specimens. Anal sinus deep, its apex round, sides straight; slightly constricted at opening on parietal wall side by a callus. Anterior canal very short, open, slightly notched at its tip; anterior fasciole not swollen; spirals subequal to that on shell base. Inner lip appressed to columella, narrow, margined, glossy, thin on parietal wall. Color variable, white to dingy white with a light brown spiral band mid-body, broken by lighter ribs; large darker brown patch on varix and irregularly between ribs, and dark patches intermittently spaced on shoulders of spire whorls.
Remarks. Taxonomy. Fenimorea caysalensis has all of the characteristics of Fenimorea: the shell microsculpture typical of the genus; ribs suture-to-suture that are modified in the sulcus, a broad hump-like varix; a deep U-shaped anal sinus, and numerous low ribs. It is one of the smallest and stoutest among its cogeners. F. caysalensis is similar in size and shape to ecotypic dwarfs of F. f u c at a (Reeve, 1845). Compare Figs. 5–8, and Figs. 18–20 of Plate 78, ecotypic dwarfs from Grand Bahama I. and Abaco I., respectively, and Figs. 7–10 of Plate 79 (dwarfs from Andros I.). There does not appear to be “normal size” or intermediate size F. f u ca t a having a similar color pattern present on Cay Sal Bank. Specimens of F. f u c at a from Cay Sal Bank (Damas Cays) are much larger and somewhat differently patterned than Dog Rocks F. caysalensis specimens. The Damas Cays specimens are shown in Figs. 22–26 Plate 70. A representative specimen of F. fucata from Honeymoon Cove is shown in Fig. 2 of Plate 79. For this reason it is believed that F. caysalensis represents a true species and not just another ecotypic dwarf. Variability. The average length of 96 specimens is 10.52 mm (8.2–14.7 mm) and average W/ L ratio is 0.449. Specimens are fairly uniform in gross shell parameters but color pattern varies between known populations. The Dog Rocks population differs somewhat from the one in Honeymoon Cove, Gun Cay (compare Plates 69 and 70). The central color band is wider although mostly confined to the intercostal space in the Dog Rocks population, whereas the Honeymoon Cove population is more like F. fucata in its color pattern, and more variable, the central color band narrower and more often continuous, not usually confined to the intercostal space. All-white specimens of what are believed to be this species have been taken from Exuma (Pl. 70, Figs. 20–21). Identification. Fenimorea caysalensis is similar to F. jongreenlawi, new species and F. glennduffyi, new species. Their average total length is comparable (10.52, 10.87, and 11.1 mm for F. caysalensis, F. jongreenlawi, and F. glennduffyi, respectively); however, other shell parameters differ. F. caysalensis has a stouter shell (W/L = 0.449 versus 0.405 and 0.418 for F. jongreenlawi and F. glennduffyi, respectively), and a proportionately larger height of the last whorl (66% versus 64% and 63% for F. jongreenlawi and F. glennduffyi, respectively). There are differences in other characters, namely sculpture and color. F. caysalensis has more axials than either of the other two species. Fenimorea caysalensis has a scalloped outer lip, not smooth as in F. jongreenlawi, and spiral lines on the shell base more widely spaced and ridge-like. It is more darkly colored than F. jongreenlawi, and differently patterned than F. glennduffyi. From F. biminensis, new species it differs in being more robust (W/L average = 0.449 versus 0.391), and it has a different color pattern. From F. f a ba e, new species it differs in possessing distinct ribs, spiral grooves and teeth on the outer lip edge, and a distinct sulcus. From F. cul exensis Usticke, 1969 it differs in possessing a round last whorl, not squarish, a less angular shoulder, teeth on the edge of the outer lip, not small bumps, and it has a different color pattern. The all-white forms differ from F. nivalis, new species principally in the acuminate shape of the spire.
Etymology. The Cay Sal Bank Fenimorea. Named after its type locality and known principal area of occurrence, Cay Sal Bank, Bahama Is.
description: Published as part of Fallon, Phillip J., 2016, Taxonomic review of tropical western Atlantic shallow water Drilliidae (Mollusca: Gastropoda: Conoidea) including descriptions of 100 new species, pp. 1-363 in Zootaxa 4090 (1) on pages 151-154, DOI: 10.11646/zootaxa.4090.1.1, http://zenodo.org/record/263299