Fenimorea chaaci (Espinosa & Rolán, 1995) Espinosa & Rolan, 1995

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 : 154-156

Fenimorea chaaci (Espinosa & Rolán, 1995) , new combination

( Plate 71 )

Drillia (Clathrodrillia) chaaci Espinoza & Rolán, 1995: 29 , figs 1–6.

Drillia chaaci (Espinoza & Rolán, 1995) : Boyko & Cordeiro (2001: 59). Clathrodrillia chaac i (Espinoza & Rolán, 1995): Williams (2005; 2009: 1549).

Type material. Holotype 19.6 x 8.5 mm (MNCN 15.05-22391); paratypes: 1 spec., 17.3 x 7.6 mm (MNHN 2857); other paratypes are in AMNH 226535, NHMUK, IES, Estación de Investigaciones Marinas de Puerto Morelos, México, and in the coll. of E. Rolán. Only the paratype in MNHN 2857 was examined.

Type locality. Puerto Morelos, Quintana Roo, Mexico, in 6– 15 m.

Other material examined. An additional 2 specimens, believed to be this species, are: 16.4 x 7.7 & 16.4 x 7.8 mm, in 1.5–4.6 m, off Cozumel I., Quintana Roo, Mexico, J. Cordy! Nov 1993 (UF 470299).

Range and habitat. Mexico (Quintana Roo: Puerto Morales; off Cancun I.; Campeche Bank: Alacran Reef). Reported from 1.5– 15 m.

Description. According to Espinosa & Rolán: Shell small (to 21 mm in total length) stoutly fusiform, truncated anteriorly, of approximately 8½ slightly convex whorls, the last 63% of total shell length. Surface glossy; ribs the predominant sculptural element; aperture wide, with a short anterior canal and deeply notched anal sinus. Protoconch smooth, round, of about 1¼ whorls. Axial sculpture of low narrow ribs with round crests that run from suture-to-suture on spire whorls, number 14–15 on penultimate; evanesce below whorl periphery on last whorl where they number about 15–16. Ribs change abruptly in sulcus, become lower and hooked to the left reflecting former positions of anal sinus. Varix low, broad, hump-like, about ¼-turn from the edge of the outer lip. Spiral sculpture of widely spaced alternating threads and grooves that run over the ribs. Grooves begin as finer threads on spire whorls then develop into grooves on the last; 5 grooves on the penultimate, 15 on the last to the anterior fasciole, and 7 spiral threads on anterior fasciole. Growth striae are dense, most evident in the grooves where they are sometimes lamellate, and oblique to the ribs, running over rib shoulders, recurved in the sulcus. Striae are weaker between grooves. Sulcus is marked by a change in the ribs, lower and hooked to the left, and has approximately 5 faint spiral threads. Outer lip thin, with several strengthening axial folds; edge of lip runs from anal sinus to anterior canal in a flat arc, edge scalloped by the projecting ends of the grooves; stromboid notch shallow. Anal sinus deep, U-shaped, and slightly constricted by parietal callus. Outer lip curves outward at sinus, spout-like. Inner lip moderately wide, erect anteriorly, recumbent on parietal wall and formed into a callus posteriorly. Anterior canal short, wide, open, notched at its tip; fasciole not swollen. Color white to off-white with variable light reddish-brown spiral banding; intercostal spaces a darker brown; varix with a patch of brown on its leading (ventral) side.

Remarks. Taxonomy. Fenimorea chaaci lacks the tall spire, acute-shouldered whorls, well-defined anterior canal, and narrow aperture shared by members of the genus Clathrodrillia . The species’ characteristics are instead more closely allied to members of the genus Fenimorea , where it is here reassigned. Specifically and most importantly, it possesses the diagnostic microsculpture of jagged spiral threads and grooves, and strong growth striae that produce rows of rectangular pits between the threads. In addition, it has the short anterior canal and hump-like varix typical of shallow-water Fenimorea , and low, broad ribs that run from suture-to-suture but are transformed in the sulcus. Identification. This species is close in general appearance to F. tartaneata , new species in they both have a similar broadly fusiform, squat profile, numerous ribs that are reduced in the sulcus, and strong spiral sculpture (threads or grooves) that override the ribs. Fenimorea chaaci differs in that the ribs are narrower with wider intercostal spaces; spirals alternate in strength, are not uniform as in F. tartaneata , and has a different coloration. Fenimorea chaaci is also similar to F. fucata but differs in shell form, having a somewhat larger last whorl (typically 60% in F. f u c at a versus 64%), and stouter shell (average W/L = 0.448 versus 0.0421), possessing deeper spiral grooves on the last whorl, having scalloping, not teeth on lip edge, and in coloration. Feniforea chaaci lacks brown patches on the whorl shoulders.

Figures

PLATE 71. Fenimorea chaaci (Espinosa & Rolán, 1995). Figs. 1 – 2: paratype, Puerto Morelos, Quintana Roo, Mexico (MNHN 2857). Fig. 1. ventral, lateral & dorsal views; Fig. 2: apical view, V = varix, L = edge of outer lip. Figs. 3 – 5: off Cozumel I., Quintana Roo, Mexico (UF 470299): Fig. 3 – 4 ventral views; Fig. 5: enlarged view of protoconch of specimen in Fig. 4 (not to scale).