Perrinia stellata (A. Adams, 1864)

Herbert, D. G., 2012, A revision of the Chilodontidae (Gastropoda: Vetigastropoda: Seguenzioidea) of southern Africa and the south-western Indian Ocean, African Invertebrates 53 (2), pp. 381-381 : 474-478

Perrinia stellata (A. Adams, 1864)

Figs 4O , 58–60

Turcica stellata: A. Adams 1864 a: 508 ; Pilsbry 1890 in 1889–90: 418, pl. 67, fig. 77; Yen 1942: 177, pl. 11, fig. 11 (holotype); Mastaller 1979: 31; Smythe 1979: 64; idem 1882: 39; Glayzer et al. 1984: 318. Type loc.: China Seas (Cuming) [erroneous, here emended to the Gulf of Suez].

Tectaria armata: Issel 1869: 192 , 289, pl. 2, fig. 7; Moazzo 1939: 183. Type loc.: Gulf of Suez, Red Sea.

Euchelus (Perrinia) stellata: MacAndrew 1870: 443 .

Turcica (Perrinia) stellata: Melvill & Standen 1901: 351 ; Tomlin 1927: 298 [= Tectaria armata Issel, 1869 ]; Melvill 1928: 98; Lamy 1938: 82, fig. 9; Biggs 1973: 350; Kilburn 1977: 176.

Calliostoma stellatum: Hidalgo 1904 –5: 255.

Tectarius armatus: Sturany 1903: 263 , 278.

Turcica (Turcica) stellata: Bisacchi 1931: 182 .

Perrinia stellata: Kendall & Skipwith 1969: 855 ; Bosch et al. 1995: 33, fig. 28; Hoenselaar & Dekker 1998: 199; Rusmore-Villaume 2008: 20; Zuschin et al. 2009: 99, pl. 9, figs 5–7; Bandel 2010: 470, fig. 15d–f.

Description:

Shell: Elevated-trochiform to turriculate (L/D=1.10–1.65); apical angle 42–63°; teleoconch of up to 8 whorls; whorls flat-sided and periphery angular, marked by strong, stellate, keel-like spiral cord, below which is a distinct supra-sutural sulcus. First teleoconch whorl rounded and sculptured only with close-set, curved, axial pliculae (± 35); weak spiral cords develop toward end of second whorl; supra-sutural cord rapidly strengthening during third and subsequent whorls, and developing characteristic squamose, stellate projections; projections becoming fewer and larger with growth (± 15 on last adult whorl); uppermost cord also strengthens, but to a lesser extent and becomes coronated by apically orientated, scale-like granules; these 1.5–2 times as numerous as peripheral projections; interval between peripheral cord/keel and abapical suture progressively deeper and more channelled with growth; development of remaining spirals between adapical suture and periphery variable, sometimes distinct, sometimes obsolete; axial sculpture becoming less obvious with growth; apical whorls (not first) somewhat cancellate, becoming more foveolate with elongate D-shaped pits on later whorls; pliculae in supra-sutural sulcus usually stronger and less close-set than those above peripheral keel. Base with 4 well-defined spiral cords and a fifth adjacent to columella; outermost cord strongest and frequently set with scale-like granules, in large specimens the other basal cords may also be somewhat granular; umbilicus closed. Peristome oblique; aperture D-shaped; columella more or less straight, a single weak tooth or rounded bulge present at its base in mature specimens; outer lip strongly notched at ends of peripheral and basal cords, particularly in subadults; interior of outer lip weakly thickened with in-running ridges at maturity, but most local material somewhat subadult in this respect; interior of aperture nacreous, angled beneath peripheral cord.

Microsculpture ( Fig. 59B, C ): Initial whorls somewhat worn in all available material, but evidently lacking vermiform spiral microsculpture; later whorls with distinct scratch-like microsculpture.

Protoconch ( Fig. 59A, C ): Apex missing or heavily encrusted in most specimens; protoconch remaining only in some juveniles and rather worn even in these; translucent white; diameter ca 260 µm; moderately exsert; terminal lip roundly angled between mid-whorl and apical suture; superficial sculpture eroded in all available material.

Colour: Shell milky-white, fresh specimens with a cream to dirty buff intritacalx deposit, often with broad, dark greyish axial bands, particularly in juveniles. Many specimens with heavy, whitish or pinkish coralline encrustation.

Dimensions: Largest specimen (holotype of Tectaria armata ), length 15.5 mm. South-east African specimens develop mature apertural features at a smaller size than those from the north-western Indian Ocean and Red Sea, and never attain such a large size (largest southern African specimen, length 9.6 mm) .

Operculum ( Fig. 4O ): Initially tightly multispiral, but whorls broadening with growth and becoming more openly multispiral, although somewhat less so than in P. angulifera and P. konos .

Radula: Unknown.

External anatomy: Like that of P. angulifera ; only small specimens available, but no clear differences are apparent.

Type material: Holotype of Turcica stellata A. Adams, 1864 ( Fig. 58A ), in NHMUK (1968214). Holotype of Tectaria armata Issel, 1869 ( Fig. 58F ), in MCSNG.

Regional material examined (all NMSA unless indicated otherwise): KENYA: Shimoni (4.6482°S 39.3814°E), dredge 1+2, J.D. Taylor ( NHMUK); ditto, dredge 6, J.D. Taylor ( NHMUK); ditto (4.6536°S 39.3799°E), dredged in channel between mainland and Wasini Is. , <12 fath. [- 22 m], coral sand, J.D. Taylor ( NHMUK); Kichangani , Shimoni , from broken fish traps, J.D.Taylor ( NHMUK). TANZANIA: Entrance to Dar-es-Salaam harbour, - 7.3 m, W. Rudman ( AMS). MADAGASCAR: Banc du Leven , NW of Madagascar (12.533°S 47.667°E), - 35–150 m, BENTHEDI Exped’n, st’n 5, dredged, 1977 ( MNHN). MOZAMBIQUE: Mozambique Is. (15.03°S 40.73°E), R. Kilburn, ix.1974 (G7930) ; Bazaruto Archipelago, 0.5 miles west of Santa Carolina Is. (21.619°S 35.332°E), 3 fath. [- 5.5 m], sand and shell debris, dredged, P. & E. Roscoe, 8.i.1976 (G7096) ; off Ponta da Barra lighthouse, ‘ Office Reef’ (23.7869°S 35.5410°E), - 24 m, dived, xi.2003 (D. Slater coll’n) ; off Lacerda Lighthouse (25.56167°S 32.84472°E), - 52–55 m, dredged, vi.2010 (J. Rosado coll’n) ; NE of Maputo, - 65 m, dredged J. Rosado, ii.2010 (D. Slater coll’n) ; off Ponta Techobanine (26.68132°S 32.95093°E), - 60 m, dredged J. Rosado, xii.2005 (D. Slater coll’n) . SOUTH AFRICA: KwaZulu-Natal: off Kosi Bay (26.905°S 32.925°E), living, - 45 m, sand, stones and large algae, dredged NMDP, RV Sardinops , st’n ZA49, 4.vi.1990 (S8937) ; Kosi Bay , main reef, 1–4 km south of estuary mouth (26.9210°S 32.8861°E), - 18 m, underwater pump, D. Herbert & K. Bloem, 6.v.1990 (S2260) ; ditto, living, - 20–22 m, underwater pump, D. Herbert & K. Bloem, 5.v.1990 (S1985) ; SE of Kosi River Mouth (26.9217°S 32.9183°E), living, - 50 m, algae, shells, dredged NMDP, RV Meiring Naude, st’n ZA20, 8.vi.1987 (E1364) ; off Boteler Point (27.0083°S 32.9117°E), - 50 m, dead coral rubble and lithothamnion, dredged NMDP, RV Meiring Naude, st’n ZB7, 6.vi.1987 (D7437) ; off Hully Point (27.3367°S 32.7700°E), - 30–40 m, fine muddy sand, dredged NMDP, RV Meiring Naude, st’n ZF7, 5.vi.1987 (E2904) ; off Sodwana Bay (27.553°S 32.686°E), - 50 m, shell and coral sand with foraminiferans, dredged CSIR Water Research (A5849); ditto, - 46 m, sediment at base of drop-off in canyon, dredged UND Marine Geoscience Unit, 7 xi.1992 (V2629) ; NE of Liefeldt’s Rocks (27.7167°S 32.6650°E), - 50 m, lithothamnion, medium sand, dead coral rubble, dredged NMDP, RV Meiring Naude, st’n ZJ6, 9.vi.1988 (E4264) ; SE of Mission Rocks (28.2917°S 32.5433°E), - 50 m, old coral rubble, lithothamnion, dredged NMDP, RV Meiring Naude, st’n ZN1, 10.vi.1988 (E7350) ; Aliwal Shoal, off Scottburgh (30.2833°S 30.8333°E), ca - 14 m, underwater pump, D. Herbert, 2.vi.1991 (S8689) ; Lander’s Reef, off Park Rynie (30.3333°S 30.8166°E), - 34 m, sand, D. Herbert, 2.vi.1991 (S6010).

Other material examined: PERSIAN GULF: Khor-al-Bazm, Abu Dhabi, H.E.J. Biggs (NMSA G6968 and NHMUK); Dabai [Dubai] R. Winckworth (NHMUK). GULF OF OMAN: Jask, Iran, R. Winckworth (NHMUK). PAKISTAN: Mekran Coast, V.W. MacAndrew (NHMUK). RED SEA: Suez, J.J. Walker and R. MacAndrew (NHMUK); Suez Canal, living, Cambridge University Exped’n (NHMUK 1928.3.30.236); Great Bitter Lake, Suez, living, dredged at - 9 m, muddy sediment with coarse sand covered thickly by Sargassum, C. Beets (H. Dekker coll’n, large specimens); Nuweiba, Sinai, beach, J. Wise (AMS); Eilat, north beach, H. Kurutz & J. Wise (AMS); Gulf of Aqaba, Dahab, south side of Ras el Kura, sand beach, coral reef, reef flat (H. Dekker coll’n); Hurghada, Egypt, R. Kilburn (NMSA L376); 16 km S of Hurghada, Egypt, sandy beach stones, dead coral, coral reef (H. Dekker coll’n). GULF OF ADEN: Aden, H. Burnup coll’n (NMSA G4296).

Distribution and habitat ( Fig. 60 ): Persian Gulf, Gulf of Oman, Arabian Sea, Red Sea, Suez Canal and East Africa south to the KwaZulu-Natal south coast (Scottburgh area); living material collected from - 18–50 m in South Africa, but probably also occurring in shallower water in truly tropical areas; available data on habitat preferences is inconclusive. A record from Zambales in the Philippines ( Hidalgo 1904 –05) requires confirmation.

Remarks:A characteristic species though somewhat variable in size and shell proportions. The only local species with which it might be confused is P. konos , but that species is smaller, never has such strongly developed peripheral projections, has weaker basal cords and more widely spaced axial pliculae on the apical whorls. Turcica (Perrinia) morrisoni Ladd, 1966 from the Marshall Islands, is smaller, less elevated and has much more obvious dentition inside the outer lip.

Tomlin (1927) followed by Lamy (1938) synonymised Tectaria armata Issel, 1869 from the Red Sea, with the present species. The figure of the holotype here provided ( Fig. 58F ) indicates that this was fully justified. Tomlin (1927) also questioned the validity of the original Cumingian locality data, China Seas. This is a notoriously vague locality which should be rejected in view of the known inaccuracy of the provenance attached to much Cuming material. With the exception of one unconfirmed record from the Philippines ( Hidalgo 1904 –05), the species has been recorded subsequently only from the western Indian Ocean. I here emend the type locality to be the Gulf of Suez.

Genus Pholidotrope gen. n.

Etymology: From Greek pholidotos (scaly) and trope (a turn); in reference to the scale-like sculpture on the spiral cords. Gender feminine.

Type species: Pholidotrope gloriosa sp. n.

Diagnosis: Shell small, profile conical with narrowly indented suture; suture level with subperipheral cord; sculpture coarsely cancellate with scale-like projections on spiral cords; columella with a single basal tooth; interior of outer lip thickened and set with ridge-like denticles, that nearest columella largest and separated from basal columella tooth by a U-shaped notch; denticles do not extend into aperture as in-running ridges; umbilical and parietal region covered by glossy inductural callus shield; aperture obliquely tangential to base of last adult whorl; outer lip with low subterminal external varix; protoconch exsert.

Remarks: Pholidotrope resembles Clypeostoma in possessing a well developed basal callus shield, but differs in being smaller, having a more conical profile, coarser sculpture, only one tooth on the columella and a subterminal external varix behind the outer lip. It also resembles Mirachelus Woodring, 1928 from the western Atlantic and eastern Pacific, but species of that genus lack an expanded basal callus and a subterminal external labral varix. Perrinia likewise lacks both these features, and in addition its aperture is spirally corded within and the dentition at the base of the columella is weaker.

Figures

Fig. 4. Operculum morphology in the Chilodontidae: (A) Littorina littorea (Linnaeus, 1758), Cancale, Brittany,France,max.diameter 10.2mm (NMSA G778);(B) Euchelus asper (Gmelin,1791),Bombay, India,max.diameter 9.0 mm (NMSA J8066);(C) Granata sulcifera, Mtwalume,KZN, max.diameter 3.58 mm (NMSA V3927); (D) Clypeostoma salpinx, off Whale Rock, Eastern Cape, max. diameter 2.59 mm (NMSA C9502); (E) Danilia textilis, max. diameter 2.97 mm (holotype, NMSA E7756/ T2595); (F) Ascetostoma providentiae, off Boteler Point, KZN, max. diameter 2.52mm (NMSA S4904); (G) Herpetopoma (s.s.) instrictum, Low Isles, GreatBarrier Reef, Queensland,max.diameter 3.17 mm (AMS C.304699); (H) H. (s.s.) scabriusculum, Bradleys Head, Sydney Harbour,Australia, max. diameter 1.78 mm (AMS C.30695); (I) H. (s.l.) helix, off Umzinto, KZN, max. diameter 1.01 mm (NMSA D5427); (J) Vaceuchelus cretaceus, SE of Kosi Bay, KZN, max. diameter 2.52 mm (paratype, NMSA S4006/T2638); (K) V. natalensis, off Umzinto, KZN, max. diameter 0.99mm (NMSA D5428); (L) V.semilugubris, Réunion, max. diameter 1.28 mm (M.Jay coll’n MNHN); (M) Perrinia angulifera, off Boteler Point, KZN, max. diameter 4.44 mm (NMSA D9209); (N) P.konos, off Port Grosvenor, Eastern Cape, max. diameter 1.23 mm (NMSA E177); (O) P.stellata, Kosi Bay main coral reef, KZN, max. diameter 1.14 mm (NMSA S1985).

Fig.58.Perrinia stellata (A.Adams, 1864):(A)holotype of TurcicastellataA.Adams,1864, length 10.9mm (NHMUK 1968214); (B) narrow specimen, NE of Liefeldt’s Rocks, KZN, length 9.6 mm (NMSA E4264);(C) subadult specimen,Mozambique Is., length 8.0 mm (NMSA G7930); (D) broadspecimen, Hurghada, Egypt, length 8.25 mm (NMSA L376); (E) small adult specimen, off Mission Rocks, KZN, length 6.9 mm (NMSA E7530); (F) holotype of Tectaria armata Issel, 1869, length 15.5 mm (MCSNG, photo courtesy of Maria Tavano).

Fig. 59. Perrinia stellata (A. Adams, 1864), off Mission Rocks, KZN (NMSA E7530): (A) juvenile shell whorls showing exsert protoconch and close-set axial pliculae on earliest teleoconch whorls, bar = 0.5 mm; (B) adult microsculpture, bar = 100 µm; (C) protoconch, bar = 100 µm.

Fig. 60. Distribution of Perrinia stellata in the south-western Indian Ocean. Each triangle represents one or more records.