Herpetopoma, : Pilsbry, 1890

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 : 429-433

Herpetopoma (s.s.) instrictum (Gould, 1849)

Figs 4G , 23–25

Trochus (Monodonta) instrictus: Gould 1849 in 1846–50: 107; 1852: 190, pl. 13, fig. 225a–c; 1862: 59; Johnson 1964: 92. Type loc.: Pacific Islands.

Monodonta alveolata: A. Adams 1853: 176 . Type loc.: ‘ Guidulman, island of Bohol, rocky ground, 60 fathoms [- 110 m]; Baclayon, island of Bohol, under stones, low water; island of Capul , on the reefs at low water’.

Monodonta bourcierei: Crosse 1863: 178 , pl. 4, fig. 6; Pilsbry 1890 in 1889–90 [= Trochus instrictus Gould, 1849 ]. Type loc.: New Caledonia.

Turcica instricta: A. Adams 1864 b: 143 .

Trochus (Euchelus) alveolatus : Smith 1876: 559.

Trochus bourcierei: Fischer 1878 in 1875–80: 249, pl. 84, fig. 3.

Euchelus alveolatus: Melvill & Sykes 1897: 172 ; Kaicher 1990: No 5706, syntype.

Euchelus instrictus: Pilsbry 1890 in 1889–90: 440, pl. 67, figs 62, 63; Hedley 1899: 405; Hidalgo 1904 –5: 256; Shirley 1911: 96; Cernohorsky 1978b: 33, pl. 8, fig. 6 [= Monodonta alveolata Adams, 1853 ]; Kaicher 1990: No 5705, holotype; Wells & Slack-Smith 1986: 44; Jansen 1996: 7, No 21 [doubtful]; Kosuge & Chino 1998: 78, pl. 25, fig. 3 [doubtful]; Chang 2003: 4, figs C–F.

Monodonta bourcieri [sic]: Smith 1897: 232.

Euchelus intricatus [sic]: Schepman 1908: 71.

Euchelus (Euchelus) alveolatus: Solem 1953: 218 .

Euchelus (Euchelus) instrictus: Hirase & Taki 1954 : pl. 70, fig. 6; Solem 1958: 217.

Euchelus instricta: Habe 1964: 10 , pl. 4, fig. 14.

Euchelus (Herpetopoma) instrictus: Ladd 1966: 33 , pl. 3. figs 11–13; Springsteen & Leobrera 1986: 36, pl. 5, fig. 10.

Euchelus bourcieri [sic]: Kaicher 1990: No 5707, type.

Euchelus (Vaceuchelus) instrictus: Fukuda 1993: 24 , pl. 6, fig. 70.

Herpetopoma instricta: Wilson 1993: 68 ; Higo et al. 1999: 52, No G280; Sasaki 2000: 57, No 18; Vilvens & Héros 2003: fig. 5; Taylor & Glover 2004: 264; Héros et al. 2007: 209.

Herpetopoma instrictum: Poppe et al. 2006: 37 , pl. 10, fig. 4; Poppe & Tagaro 2008: 174, pl. 32, figs 2, 6. not Euchelus cf. instrictus: Orr Maes 1967: 103 , pl. 3, fig. E.

Description:

Shell: Trochoid-turbiniform, moderately elevated (L/D=1.10–1.25); teleoconch of up to 6.5 whorls; spire whorls somewhat flat-sided; suture strongly indented, inserted at level of subperipheral cord and thus appearing somewhat channelled, descending slightly just prior to outer lip. First teleoconch whorls sculptured with curved axial pliculae; 2–3 spiral cords arise during second whorl, and additional ones with subsequent growth; penultimate whorl with approx. 5 well developed cords, a sixth level with suture; subsutural cord strongest, but becoming distinctly weaker just behind outer lip; cords equal to or narrower than their intervals. Axial pliculae of first whorl persist on later whorls producing a distinct cancellation and rendering spiral cords granular where they cross them; granules of subsutural cord usually largest, becoming smaller and more numerous toward periphery; interstices more or less square on spire whorls, becoming axially elongate on last adult whorl, particularly so just behind outer lip. Base similarly sculptured with approx. 6 spiral cords, the last of which forms umbilical margin; umbilicus remaining open at maturity (very occasionally almost occluded by reflected columella). Peristome oblique; aperture D-shaped, flattened parietally; columella thickened, bearing a low bulge in the mid region and a well-developed, peg-like tooth basally; a deep U-shaped notch separates basal columella tooth from first denticle of basal lip; parietal callus not extending far beyond aperture, bearing spiral ridges; margin of outer lip somewhat flaring, the edge finely and rather irregularly crenulate; interior of outer lip with a subterminal thickening which is set with relatively strong, in-running, ridge-like denticles, these become weaker toward lip margin and develop finer intermediaries (at maximal maturity); denticles not extending far into aperture, one nearest basal columella notch usually larger; 1 or 2 small rounded granules may be present on columella near bottom of basal columella notch; interior of aperture nacreous; exterior of outer lip sometimes with a broad low subterminal thickening, but lacking a rib-like varix.

Microsculpture ( Fig. 24A–C ): Juvenile shell with vermiform spiral threads; later whorls with close-set, scratch-like marks beneath intritacalx.

Protoconch ( Fig. 24A, C ): White, more or less level with first teleoconch whorl or at most weakly exsert, with a weak apical beak; diameter 220–240 μm; terminal lip distinctly convex; superficial sculpture well developed, arranged in irregular axial lines, with a weak spiral element.

Colour: White to yellowish white, later whorls with reddish to brown spots, blotches or axial flames; markings generally browner in fresh specimens; a white to dirty brown intritacalx is present in fresh specimens but this is worn off in most museum material. Shell surface often encrusted by other marine organisms.

Dimensions: Largest specimen seen, length 11.9 mm, diameter 10.0 mm (lectotype of Monodonta alveolata A. Adams, 1853 ).

Operculum ( Fig. 4G ): Initially tightly multispiral, but whorls broadening with growth and becoming more openly multispiral.

Radula and external anatomy: Unknown except for some brief comments on the external anatomy made by A. Adams (1864 b). A figure of a living specimen was also provided by Sasaki (2000: 56).

Type material: Holotype of Trochus instrictus Gould, 1849 , in USNM (5625) ( Fig. 23A, B see also Kaicher 1990), length 8.3 mm, diameter 7.5 mm (measured from photograph scale, dimensions given by Gould equate to 9.5× 7.6 mm); four syntypes of Monodonta alveolata A. Adams, 1853 in NHMUK (196872), the best of which is here figured and designated lectotype, length 11.9 mm, diameter 10.0 mm ( Fig. 23E, F ); holotype of Monodonta bourcierei Crosse, 1863 in NHMUK (96.12.1.13), length 8.6 mm, diameter 7.0 mm ( Fig. 23G, H ).

Regional material examined: KENYA: Kilifi (3.60236°S 39.81190°E), ca - 4 m, lagoon inshore of coral reef, sand from base of coral outcrops, D. Herbert, 20 xii.1991 (K8265); Shimoni , SE of Wasini Is. (4.65°S 39.39°E), J.D. Taylor ( NHMUK) ; Shimoni area, Shungalunzi (1.2 km east of Shimoni ) (4.67°S 39.41°E), J.D. Taylor ( NHMUK) . COMOROS: Mayotte (12.87°S 45.09°E), V.W. MacAndrew coll’n ( NHMUK) . MADAGASCAR: Ouest Cap Antsirabe (25.04167°S 46.99500°E), - 4–5 m, fond rocheux en limite de platier, Exped’n ATIMO VATAE, st’n TS12, 9.v.2010 ( MNHN) ; Pointe d’Ambero (25.11167°S 46.83167°E), intertidal substrat dur, mode battu, Exped’n ATIMO VATAE, st’n TM16, 08.v.2010 ( MNHN) ; Baie des Galions (25.1483°S: 46.7567°E), intertidal, platier rocheux et sable, Exped’n ATIMO VATAE, st’n TM21, 12.v.2010 ( MNHN) . MOZAMBIQUE: Pemba (12.937°S 40.521°E), J. Rosado, x.1993 ( NMSA L2055 ) ; ditto, living amongst dead coral in shallow subtidal, J. Rosado, xi.2010 ( NMSA L8398 ) ; ditto, Praia do Uimbe, amongst dead coral in shallow subtidal, J. Rosado, xi.2010 (J. Rosado coll’n); Conducia Bay (14.9128°S 40.7178°E), K.J. Grosch, purch. ix.1975 ( NMSA J4175 ) .

Other material examined: ANDAMAN ISLANDS: Port Blair area, E.M. Man (NMSA F7170); same, Winckworth coll’n (NHMUK). PHILIPPINES:Matabugkay, 115 km SSW of Manila, short algae on reef flat, W. Ponder (AMS); Punta Engaño, Mactan Is., Cebu, deep-water shell grit, F.J. Springsteen (NMSA K2549); Palawan Is., Tadio Is., coral rubble washings, low tide patch-reef, W.Ponder (AMS); beach at Santa Cruz Is., off Zamboanga, Mindanao, A.J. Meagher (AMS C.71800); west of Zac Is., Pearl Bank, Sulu Archipelago, coarse sand (WAM). PAPUA-NEW GUINEA: Bougainville Straits, W. Burrows (AMS); East Cape, Papua, H.T. Williams (AMS); Kuia Is., Lusancay Islands, Trobriand group [Kiriwina], Ponder & Colman (AMS);

ditto, near Okaiboloma village , rubble and algae washings, living Ponder & Colman ( AMS) . AUSTRALIA: Western Australia: Kendrew Is., Dampier Archipelago, - 27–28 m ( WAM) ; ditto, in Caulerpa washings from reef flat ( WAM) ; ditto, transect 1, C.o.T. survey, - 67–68 m ( WAM) ; ditto, transect 2, C.o.T. survey, - 146–147 m ( WAM) ; ditto, under rocks ( WAM) ; Lighthouse Beach, NW Cape, shell sand, L. Figgis ( AMS C.304705); north of Tantabiddi , NW Cape, at base of outer reef slope ( WAM) ; Turtle Bay , NW Cape, J. Hewitt ( WAM) ; Quobba, Hewitt, Plant, Buick ( WAM) . Queensland: Bramble Cay, Torres Strait, C. Hedley ( AMS C.051290); Darnley Is., Torres Strait , under stones on shore, Chevert Exped’n ( AMS C.061508); Murray Is. , Torres Strait, C. Hedley ( AMS C.29253); Rocky Isle , off Cape Flattery, C. Hedley ( AMS C.041235). Great Barrier Reef : south end of Lizard Is. , - 15 m, on outer side of reef, W. Ponder ( AMS) ; Three Isles, north of Cooktown , Iredale ( AMS) ; Arlington Reef, intertidal, living, I. Loch ( AMS) ; Low Isles, living, British GBR Exped’n 1928 ( AMS C.304699); Low Isles, J. Hewitt ( WAM) ; Michaelmas Cay, GBR Boring Exped’n 1926 ( AMS C.304704); North West Is., Capricorn Group, J. Kerslake coll’n ( AMS C.304701). CORAL SEA: NE Herald Cays (16.95°S 149.17°E), D.F. McMichael & J.C. Yaldwyn, xi.1964 ( AMS C.304700). NEW CALEDONIA: Nouméa, R.C. Rossiter ( AMS C.003734). TUVALU: Funafuti Atoll, R. Soc. Coral Boring Exped’n 1896 ( AMS C.005838). FIJI: Nadi Bay, Viti Levu , - 9–35 m, J. Laseron ( AMS) .

Distribution and habitat ( Fig. 25 ): Indo-West Pacific; from southern Japan, SE Asia and the south-western Pacific to western Australia, the Andaman Islands and East Africa; in the western Indian Ocean extending south to southern Madagascar, but not yet recorded from central or southern Mozambique, or South Africa. Recorded from Quaternary deposits in the Marshall Islands ( Ladd 1966). Little information regarding the habitat of living animals is available. Adams (1864 b) reported a living specimen dredged at 55 fath. [- 100 m] off southern Japan, but most of the specimens available (live and dead collected) have come from near-shore reef systems with a coralline facies (AMS and WAM material). Wilson (1993) gave the bathymetric distribution as intertidal to - 140 m, but did not specify whether this concerned living or dead material. Sasaki (2000) cited the habitat as intertidal and upper subtidal, on coral rubble, and in northern Mozambique, J. Rosado has collected it alive amongst dead coral in the shallow subtidal.

Remarks:The synonymy of Trochus instrictus Gould, 1849 , Monodonta alveolata Adams, 1853 and M. bourcierei Crosse, 1863 has been noted previously on several occasions (e.g. Pilsbry 1890 in 1889–90; Cernohorsky 1978 b; Kaicher 1990). Other species with similar apertural dentition and umbilical form include H. crassilabrum (Sowerby, 1905) from Sri Lanka, H. exasperatum (A. Adams, 1853) from the Philippines, H. gemmatum (Gould, 1845) from Hawaii, and H. seychellarum (G. & H. Nevill, 1869). H. exasperatum ( Fig. 68E, F ) and H. seychellarum ( Fig. 29 ), however, are much less elevated, whilst H. gemmatum and H. crassilabrum ( Fig. 68C, D ) have more rounded whorls with relatively close-set and more obviously beaded spiral sculpture, the latter also has a more strongly developed upper columella denticle and a partially occluded umbilicus; all are smaller than H. instrictum . Amongst south-western Indian Ocean chilodontid taxa, only H. seychellarum retains a simple and deep umbilicus when mature, but that species is considerably smaller and more depressed.

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. 23. Herpetopoma instrictum (Gould, 1849): (A, B) holotype of Trochus instrictus Gould, 1849, length 8.3 mm, diameter7.5 mm (USNM 5625);(C, D) Conducia Bay, northern Mozambique,length 9.0mm, diameter 7.7 mm (NMSA J4175); (E, F) lectotype of Monodonta alveolata A. Adams, 1853, length 11.9 mm, diameter 10.0 mm (NHMUK 196872); (G, H) holotype of Monodonta bourcierei Crosse, 1863, length 8.6 mm, diameter 7.0 mm (NHMUK 96.12.1.13).

Fig.24.Herpetopoma instrictum(Gould, 1849), Low Isles, Great Barrier Reef,Queensland (AMSC.304699): (A) shell apex,bar = 250 µm; (B) adult microsculpture,bar = 200 µm; (C) protoconch, bar = 100µm.

Fig.25.Distribution of Herpetopoma instrictum in the south-westernIndian Ocean.Each triangle represents one or more records.

Fig.68.Ascetostomaand Herpetopoma species examined forcomparison:(A,B) Euchelus ringens Schepman, 1908, holotype, Sulu Archipelago, Indonesia, length 7.8 mm, diameter 7.5 mm [not length 7.5 mm, diameter 8.0 mm as given bySchepman] (ZMAN 3.08.092); (C, D)Clanculus crassilabrum Sowerby, 1905,one of three syntypes,specimen marked with an X, Sri Lanka, length 7.0 mm, diameter 6.4 mm (NHMUK 1905.10.23.41–43); (E, F) Monodonta exasperata A.Adams, 1853, one of four syntypes, Sibonga Is. [Cebu], Philippines, length 6.0 mm, diameter 6.5 mm (NMHUK 196875).

Fig. 29. Herpetopoma seychellarum (G. & H. Nevill, 1869): lectotype (here designated) of Euchelus seychellarum G. &H.Nevill, 1869,diameter 2.8 mm (Indian Museum,Kolkata,M13143/2; photographs courtesy of R. Kilburn).