Parachondria (Chondropomorus) silvaticus, Watters, G. Thomas, 2016

Watters, G. Thomas, 2016, Review of the Hispaniolan Parachondria (Chondropomorus) complex (Gastropoda: Littorinoidea: Annulariidae), Zootaxa 4127 (2), pp. 245-275 : 257-258

Parachondria (Chondropomorus) silvaticus new species

Figures 2 W–AB, 5 B

Type material. UF 216479, holotype, 12.1 mm; UF 216479, paratype, 10.0 mm.

Type locality. 680 m elevation, NE slope of Loma La Vigía, 15 km SW of Piedra Blanca, Monseñor Nouel Province, Dominican Republic.

Distribution and habitat. Known only from the type locality on sedimentary rocks of the Late Cretaceous Duarte Formation on the northeastern slopes of the Cordillera Central, in a deep ravine in mesic forest. A single record for 680 m elevation.

Material examined (2 specimens). Dominican Republic. UF 216479(2), 680 m, NE slope of Loma La Vigía, 15 km SW of Piedra Blanca, Monseñor Nouel Province.

Description. Shell small for genus, solid, high-spired, elongate conic. Maximum adult size: 12.1 mm, decollate. Minimum adult size: 10.0 mm, decollate. Adult shell decollated, protoconch unknown. Teleoconch of 4.75 whorls. Axial sculpture of final whorl of relatively few (70–80) thin, widely spaced threads. Spiral sculpture of final whorl outside of umbilicus of 14–16 cords; one below suture, 3–4 strong additional cords between suture and periphery, remainder on anterior half of whorl, but weaker. Cords are strong enough to render outline slightly carinate. Intersections of axial and spiral sculpture form coarse fenestrations. Umbilicus bounded by single strong cord, smooth within. Suture narrow, deep. Tufts composed of 1–2 slightly enlarged threads in irregularly spaced groups. Aperture teardrop-shaped, lip double. Inner lip erect but barely exserted. Outer lip evenly expanded, but narrower facing umbilicus, slightly recurved abaperturally. Adnate with previous whorl. Posterior auricle lacking or weakly developed. A more prominent undulating auricle present at 8 o’clock position. Color pattern complex and variable. Base color tan with ca. 7 interrupted bands of brown, square or “X”-shaped markings, becoming more continuous towards umbilicus. Inner lip and both sides of outer lip with dark brown markings. Tufts white. Operculum corneous, paucispiral, lacking calcification.

Variation in specimens. Only two specimens seen.

Comparison with other species. This is one of the smallest species within the Hispaniolan Chondropomorus. Although it has among the fewest axial and spiral threads, the sculpture is not well-developed and does not appear as coarse as the similar P. trachydermus .

Remarks. This species appears to be geographically isolated from all other congeners. Etymology. L. silvaticus , of the woods.

Figures

FIGURE 2. A – H. Parachondria (Chondropomorus) gnotus (Pilsbry, 1935). A. Chondropoma soror Pilsbry, 1933, holotype, ANSP 44344 a, ca. 13.5 mm. B. Chondropoma gnote kriegeri Bartsch, 1946: NMNH 471997, holotype, 13.5 mm. C, D. UF 216404, 13.5 mm. E. UF 216404, 12.8 mm. F. UF 216392, 15.1 mm. G. UF 216404, detail of spire. H. UF 216404, detail of suture.