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

Watters, G. Thomas, 2016, Review of the Hispaniolan Parachondria (Chondropomorus) complex (Gastropoda: Littorinoidea: Annulariidae), Zootaxa 4127 (2), pp. 245-275 : 265

Parachondria (Chondropomorus) isabellinus new species

Figures 3 X–AD, 5 B

Type material. UF 216474, holotype, 14.6 mm; UF 216474, paratype 1, 18.5 mm; UF 216474, paratype 2, 17.6 mm; UF 216 474, paratype 3, 17.7 mm; UF 216474, paratype 4, 17.5 mm.

Type locality. 620 m elevation, 2 km NW of Los Pinos, Independencia Province, Dominican Republic.

Distribution and habitat. Upland slopes of mountain ranges facing Lago Enriquillo: Sierra Neiba to the north and Sierra de Baoruco to the south. Under talus, boulders, and leaf litter in karst, mesic terrain and sub-mesic open forests. Some of the range is now in coffee groves.

Material examined (101 specimens). Dominican Republic. UF 216526(2), 150 m, 6 km NW of Postrer Río, Independencia Province; UF 216475(9), 1090 m, 10 km NNW of Los Pinos, Independencia Province; UF 216483(1), 700 m, 4 km N of Los Pinos, Independencia Province; UF 216488(11), 600 m, 3 km W of Los Pinos, Independencia Province; UF 216474(8), 620 m, 2 km NW of Los Pinos, Independencia Province; UF 216621(46), 300 m, 9 km NE of La Descubierta, Independencia Province; UF 216617(24), 250 m, 6 km NE of La Descubierta, Independencia Province.

Description. Shell thin but opaque, high-spired conic. Maximum size: 19.8 mm, non-decollate. Minimum size: 13.9 mm, non-decollate. Adult shell usually not decollated, protoconch of 1.5 minute, smooth whorls, white or tan with dark brown suture at apex, demarcation between protoconch and teleoconch not well-defined. Teleoconch of 5–5.25 whorls. Axial sculpture of final whorl of numerous (140–150) 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 25–30 fine threads, of same width as axial threads. Intersections of axial and spiral sculpture form minutely fenestrated surface but polished aspect of sculpture lends a plastic look to shell. Spiral sculpture continues into umbilicus with ca. 15 threads or weak spiral cords, inside smooth. Suture narrow, channeled, deep. Tufts composed of 1–3 numerous, regularly spaced, slightly enlarged axial threads. Aperture oval, lip single. Inner lip absent. Outer lip expanded, much narrower facing umbilicus, solute from previous whorl. Posterior edge with narrow auricle; anteriorly somewhat auriculate as well. Color ranges from nearly unicolored to having pale complex pattern. Base color white, gray, or tan. Pale axial zig-zags or minute spots on growth marks, may have pale band bordering umbilicus. Some specimens have broad, brown band deep within umbilicus. Early teleoconch whorls may be dark brown or purplish. Sculpture including tufts white, polished. Operculum corneous, paucispiral, lacking calcification.

Variation in specimens. Shells vary in the degree of coloration but all are generally quite pale. The presence of a brown band in the umbilicus varies as well; this feature seems to occur only in the overall darker specimens. Other characteristics are rather constant.

Comparison with other species. See under P. daedalus .

Etymology. Isabelline, pale grey-yellow, pale cream-brown. “Isabella” is the name for a color. The derivation of name is unclear but with several intriguing possibilities that the reader may investigate.

Figures

FIGURE 3. A – G. Parachondria (Chondropomorus) daedalus new species. A, B. UF 216481, holotype, 15.6 mm. C. UF 216481, paratype 2, 16.4 mm. D. UF 23177, 17.5 mm, note web in umbilicus. E. UF 216481, paratype 1, 13.0 mm. F. UF 216481, holotype, detail of spire. G. UF 216481, holotype, detail of suture.