Parachondria (Chondropomorus) petitianus Pfeiffer 1850
Creators: name: Watters, G. Thomas
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Pomatiidae
Parachondria
Parachondria petitianus

description: Parachondria (Chondropomorus) petitianus (Pfeiffer, 1850)
Figures 2 P–V, 5 A
Type material. NHMUK 42/10(3), syntypes. Label reads " Type set - probable type in tube (13mm), photo - photo sent to Bartsch 1938."
Type locality. “ in insula Haiti.” Restricted here to 13 km NE of Pizarrette, San Cristóbal Province, Dominican Republic.
Type figured. Pfeiffer, 1854, pl. 37, figs. 23 and 24 are probably the figured type.
Cresonymy. Cyclostoma petitianum Pfeiffer, 1850: 78 –79; Pfeiffer, 1854: 277–278, pl. 37, figs. 23, 24; Watters, 2006: 399.
Chondropoma petitianum (Pfeiffer, 1850). Pfeiffer, 1851: 173; Pfeiffer, 1852a: 291; Pfeiffer, 1852b: 45; Adams & Adams, 1858: 295; Hjalmarson & Pfeiffer, 1858: 142; Bland, 1861: 355; Reeve, 1863: pl. 5, fig. 34; Pfeiffer, 1865: 155; Pfeiffer, 1876: 196; Kobelt, 1880: 277; Weinland, 1880: 346; Crosse, 1891: 174.
Chondropoma (Chondropomorus) petitiana (Pfeiffer, 1850). Henderson & Bartsch, 1920: 61; Clench & Aguayo, 1937: 65 –66.
Chondropoma (Chondropomorus) petitianum (Pfeiffer, 1850). Pilsbry, 1933: 123 –124.
Chondropoma (Chondropomorus) petitianum petitianum (Pfeiffer, 1850). Bartsch, 1946: 18, 20, pl. 2, fig. 2.
Parachondria (Parachondria) petitianus petitianus (Pfeiffer, 1850). Watters, 2006: 46.
Chondropomorus petitianus petitianus (Pfeiffer, 1850). Watters, 2006: 399.
Distribution and habitat. Generally below 300 m on the southeastern edge of the Paralta Belt, a series of Eocene–Oligocene sedimentary sequences of the southeastern Cordillera Central. UF 216729 and UF 216729 refer to two localities in San Cristóbal Province that have not been located. However, two localities of the same name occur in Monte Plata Province. If the province name is actually Monte Plata then this species continues along the eastern edge of the Cordillera Central to the Cordillera Oriental but additional collections are needed to establish this extension. Found under leaf litter and talus, on limestone ridges in mesic, canopied canyons, forests, and in scrub thickets.
Material examined (32 specimens). Dominican Republic. UF 23219(2), 70 m, 13 km NE of Pizarrette, San Cristóbal Province; UF 216420(1), UF 216727(6), 110 m, 13 km NNW of Pizarrette, Peravia Province; UF 216724(1), 310 m, 3 km N of El Recodo, Peravia Province; UF 216563(1), UF 216564(3), 310 m, 3 km N of El Recodo, Peravia Province; UF 216729(1), 185 m, 10 km SW of Trinidad, Monte Plata Province; UF 216733(2), 220 m, 13 km NW of Sabana Grande de Boya, Monte Plata Province; UF 216747(4), 3 km E of El Majagual, San Cristóbal Province; UF 216740(11), 4 km E of El Majagual, San Cristóbal Province; UF 216748(1), 5 km E of El Majagual, San Cristóbal Province; UF 216746(1), 1 km W of El Majagual, San Cristóbal Province.
Redescription. Shell small for genus, solid, opaque, high-spired, elongate conic. Maximum adult size: 15.2 mm, decollate. Minimum adult size: 10.9 mm, decollate. Adult shell decollated, protoconch lost in examples seen; Bartsch (1946) gave 2+ whorls for protoconch. Teleoconch with 5 remaining whorls in decollated shells. Axial sculpture of final whorl of numerous (ca. 180) minute, very fine threads separated by same width as threads. Shell with regularly spaced growth stoppage marks, axial threads preceding marks often microscopic and densely packed. Spiral sculpture of final whorl outside of umbilicus obsolete, visible only as weak, axially elongated beads where they cross axial threads. Overall sculpture nearly microscopic, white axial beads give frosted appearance. Umbilicus bounded by 4–6 very weak cords, smooth within. Suture very narrow, not channeled. Tufts composed of 1–3 only slightly enlarged axial threads that are strongest just preceding each growth mark. Aperture oval, lip double. Inner lip weakly expanded, not exserted, fused to outer lip. Outer lip evenly expanded, narrower facing umbilicus, adnate to barely solute with previous whorl. Weak posterior auricle present. Color pattern complex and variable. Base color tan. Growth marks with axially aligned brown or tan zig-zags, spots, or diagonal marks. At least one more or less continuous brown band bounding umbilicus. Tufts and sculpture white. “Operculum paucispiral with the nucleus half-way between subcentral and marginal” fide Bartsch (1946: 18); lacking in all specimens examined here.
Variation in specimens. Specimens are remarkably uniform in all characteristics.
Comparison with other species. From the other high-spired species it has much finer sculpture than either P. trachydermus or P. silvaticus. From P. gnotus it differs in having better developed sutural tufts and in having even finer sculpture (ca. 120 axial threads in P. gnotus vs. ca. 180 axial threads in P. petitianus).
Remarks. Bartsch (1946) divided this species into five widely scattered subspecies: Chondropoma p. costatum Weinland, 1880, from Samaná Bay; C. p. dominicum Bartsch, 1946, from Puerto Plata (both = P. trachydermus Pilsbry, 1933), C. p. dessalinesi Bartsch, 1946, from Thomazeau, Haiti, “ C. p. hispaniolae Clench & Aguayo, 1937 ” (non Clench & Aguayo, 1937 = P. arcisensis), from Milot, Haiti; and the nominate subspecies C. p. petitianum (Pfeiffer, 1850) from “ in insula Haiti.” Based on their shell morphology, their isolation, and the narrow ranges of similar species, I believe these are distinct species.
Original description. Pfeiffer (1850: 78–79) (translated here from Latin). “Shell scarcely subperforate, oblong-turrited, truncate, spiral elevated lines about equally distant and crowded plications cross over that sculpture, a little shining, white, brown marbling and broken bands; suture separate and irregularly crenulated; 5– 5½ slightly convex whorls, slowly becoming larger, the last not solute; aperture subvertical, oval; peristome double, inner one short, outer one broadly expanded, brown-spotted, top subauriculate, cut off from previous whorl, left margin narrow.—Operculum membraneous, brown, paucispiral.”
Etymology. Sauveur Abel Aubert Petit de la Saussaye (1792–1870), French conchologist, editor of the Journal de Conchyliologie (1850–1853).
description: Published as part of Watters, G. Thomas, 2016, Review of the Hispaniolan Parachondria (Chondropomorus) complex (Gastropoda: Littorinoidea: Annulariidae), pp. 245-275 in Zootaxa 4127 (2) on pages 256-257, DOI: 10.11646/zootaxa.4127.2.2, http://zenodo.org/record/271772