Parachondria stigmosus, Watters, G. Thomas, 2016

Watters, G. Thomas, 2016, Review of the Hispaniolan Parachondria (Chondropomorus) complex (Gastropoda: Littorinoidea: Annulariidae), Zootaxa 4127 (2), pp. 245-275 : 271-273

Parachondria stigmosus new species

Figures 4 AG–AM, 6 A

Type material. UF 216426, holotype, 15.0 mm; UF 216426, paratype 1, 15.3 mm; UF 216426, paratype 2, 13.6 mm; UF 216 426, paratype 3, 11.6 mm; UF 216426, paratype 4, 13.9 mm.

Type locality. 850 m elevation, 7 km NNE of Polo, Barahona Province, Dominican Republic.

Distribution and habitat. Karst terrain in mountains surrounding Bahía de Neiba: the isolated Sierra Martín García of the Sierra Neiba on the northeastern side of the bay and the Sierra de Baoruco on the southwestern side. Under rocks, rubble, and in ravines, in dense mesic forest to at least 1000 m elevation. Part of its range is within the Parque Nacional Sierra Martín García; other parts are now coffee groves.

Material examined (83 specimens). Dominican Republic. UF 216425(14), 560 m, W slope of Loma del Aguacate, Sierra Martín García, Barahona Province; UF 216424(13), 1000 m, W slope of Loma del Aguacate, Sierra Martín García, Barahona Province; UF 216473(1), 700 m, W slope of Loma del Aguacate, Sierra Martín García, Barahona Province; UF 216427(20), 850 m, W slope of Loma del Aguacate, Sierra Martín García, Barahona Province; UF 155901(1), 100m, 6 km S of Barahona, Barahona Province; UF 216423(7), 1000 m, 7 km NNE of Polo, Barahona Province; UF 216426(15), 850 m, 7 km NNE of Polo, Barahona Province; UF 216627(12), 910 m, 14 km S of Cabral, Barahona Peninsula.

Description. Shell solid, opaque, conic. Maximum size: 15.3 mm, non-decollate. Minimum size: 11.0 mm, non-decollate. Adult shell usually not decollated, protoconch of 1.5 minute, smooth whorls, white with dark brown suture at apex, demarcation between protoconch and teleoconch not well-defined. Teleoconch of 5–5.5 whorls.

Axial sculpture of final whorl of numerous (120–130) very fine, flattened threads separated by spaces equal to or less than width of threads. Shell with regularly spaced growth stoppage marks, axial threads preceding marks microscopic and densely packed. Spiral sculpture of final whorl outside of umbilicus of 30–40 fine threads, the same width as axial threads. Intersections of axial and spiral sculpture form minutely fenestrated surface. Umbilicus with ca. 3–4 weak spiral cords, inside smooth. Suture narrow, deep. Tufts composed of 1–4 enlarged, irregularly spaced, almost blade-like axial threads. Aperture oval, lip single. Inner lip absent. Outer lip very narrowly expanded, slightly narrower facing umbilicus, solute with or just touching previous whorl. Posterior edge with wide angle but lacking auricle. Color pattern complex and variable. Base color white or tan. Between suture and umbilicus are 4–5 spiral rows of small brown spots aligned axially on white background along growth marks, anterior-most series forming almost continuous band. Two additional broken bands bound umbilicus. All of these bands are rarely smudged into larger spots. Both sides of outer lip with dark brown markings. Interior of peristome tan or pale yellowish. Tufts white. Operculum corneous, paucispiral, lacking calcification.

FIGURE 5. A–B. Distribution maps. All maps Google TM Earth Pro. Image Landsat. © 2016 Google. Data: SIO, NOAA, US Navy, NGA, GEBCO. A. P. anatolensis (orange); P. arcisensis (purple); P. caricae (yellow); P. coroni (red); P. gnotus (green); P. m uc h ai (blue); P. petitianus (white). B. P. daedalus (white); P. hispaniolae (green); P. isabellinus (red); P. silvaticus (blue); P. trachydermus (yellow); P. olssoni (purple).

FIGURE 6. A–B. Distribution maps. All maps Google TM Earth Pro. Image Landsat. © 2016 Google. Data: SIO, NOAA, US Navy, NGA, GEBCO. A. P. dessalinesi (green); P. heatheraikenae (blue); P. trachydermus (yellow); P. samanicolus (yellow); P. pilsbryi (purple); P. salleanus (white); P. stigmosus (red). B. Approximate locations of Bartsch’s (1946) locality records.

Variation in specimens. This species greatly varies in the degree of coloration, from pale, sparsely spotted specimens (common) to those in which the spots coalesce into much larger blotches (rare). Nevertheless, overall the shells are consistently low-spired and solid with well-developed sutural tufts.

Comparison with other species. Parachondria muchai most closely resembles this species although the two occur on different mountain ranges. Parachondria muchai has fewer spiral threads on the final whorl outside of the umbilicus (20–25) than does P. stigmosus (30–40). The tufts of P. muchai are more regularly distributed and are usually composed of a single node (rarely 2); the tufts of P. stigmosus are irregularly placed and usually composed of 1–4 fused tufts.

Remarks. The single-lipped taxa P. stigmosus , P. salleanus , and P. muchai are very similar and may form a distinct genus-level taxon apart from the remainder of the group covered here.

Etymology. L. stigmosus , spotted, full of marks.

Figures

FIGURE 4. A – H. Parachondria (Chondropomorus) olssoni (Pilsbry, 1933). A, B. ANSP 160978 a, holotype, 14.5 mm. C, D. UF 119142, 14.4 mm. E. UF 158947, 14.7 mm. F. GTW 6834 a, 15.5 mm. G. GTW 6834 a, detail of spire. H. GTW 6834 a, detail of suture.