Otitoma cyclophora ( Deshayes, 1863 ) Kilburn, 2004

Kilburn, Richard N., 2004, The identities of Otitoma and Antimitra (Mollusca: Gastropoda: Conidae and Buccinidae), African Invertebrates 45, pp. 263-270 : 265-269

Otitoma cyclophora ( Deshayes, 1863) , comb. n.

Figs 2–14

Pleurotoma cyclophora Deshayes, 1863: 111 , pl. 12, figs 19–21. Type locality: Réunion Is .

Hemidaphne cyclophora: Hedley 1922: 332 , pl. 54, fig. 168; Hasegawa, Okutani & Tsuchida 2000: 663, pl.

330, fig. 221.

Daphnella (Hemidaphne) cyclophora: Powell 1966: 124 ; Cernohorsky 1978: 160, pl. 57, fig. 4; Higo,

Calloman & Goto 1999: 328.

Daphnella crenulata Pease, 1868: 221 , pl. 15, fig. 20; Tryon 1884: 304, pl. 25, fig. 55; Johnston 1994: 11,

pl. 7, fig. 3 (lectotype). Syn. n. Type locality: Polynesia [ Howland Island, restricted Johnston

1994].

Antimitra crenulata: Powell 1966: 135 .

Otitoma ottitoma Jousseaume, 1898: 106 . Syn. n. Type locality: Aden [here restricted] and Djibouti.

Ottitoma ottitoma [sic]: Fulton 1922: 27.

Description (based on series from northern Mozambique, Figs 3–8 ): Shell fusiformcylindrical, breadth/length 0.26–0.35, aperture length/total length 0.38–0.48; spire somewhat cyrtoconoid, suture shallow, whorls weakly convex, last whorl subcylindrical, slightly asymmetrical (base inclined to right), aperture narrowly elliptical, slightly constricted at entrance to siphonal canal, latter short, terminally slightly expanded, somewhat obliquely truncate, very shallowly indented. Outer lip shallowly convex and opisthocline in side view, stromboid notch strong and bevelled, anal sinus deep and lacrimiform, opening strongly constricted by parietal pad; interior of outer lip smooth, columella microscopically rugose.

Sculptured by thin spiral ridges, subsutural cord ill­defined, somewhat impressed on later whorls, growth lines coarse, often rendering the spirals weakly granular, regularly finely plicate in intervals on latter part of last whorl, occasionally forming

2 3 4 5 6 7 8

9 10 11 12 13 14

irregular axial riblets elsewhere. Spiral ridges much narrower than their intervals (mostly approx. 0.2 their width, on base sometimes subequal to them), 5–6 relatively close spirals on teleoconch I, 6–9 on penultimate whorl (excluding subsutural cord), 22–25 on last whorl (15–18 on outside of terminal varix), the basal 7 sometimes higher, rounder and more sharply incised than the others, sometimes weak and angular; 1–2 ridges bordering subsutural cord are finer than the others. Sulcus illdefined; subsutural cord distinct; initially similar in strength to spiral ridges but separated by a minutely wider gap and forming a slight shoulder at suture, from second whorl subsutural cord is convex (but little stronger) and nodular; on last whorl the subsutural cord becomes flattened, with two thin, undulating spiral threads and lunulate growth lines. Intervals between spiral ridges with dense, microscopic spiral striae.

Colour uniform pale buff, protoconch white.

Protoconch bluntly papillose, of approx. 1.7 convex whorls, superficially smooth but under high magnification dense, somewhat spirally­aligned granules (see Fig. 8 ) are visible; suture deep; breadth 0.52–0.59 mm.

Operculum present, unguiform with terminal nucleus (neotype).

Dimensions NMSA (H376, largest and smallest examples): 10.9 x 3.5 mm, 7.7 x 2.1 mm.

Type material: Pleurotoma cyclophora : types evidently lost (not traced in MNHN nor UCBL).

Daphnella crenulata : lectotype (des. Johnston 1994) ANSP 15694 , paralectotype MCZ 221177 .

Otitoma ottitoma : no types are extant amongst the Jousseaume collection in the MNHN. However, a specimen in the Melvill­Tomlin collection ( NMWC 1955.158.33.58) from Aden, identified as O. ottitoma , is accompanied by a label (in Hugh Fulton’s handwriting, teste Ms A. Trew, 6/iv/94) stating “named by Dr Jouss. 31/ 7/95 (not yet named)”. This shell might be interpreted as a syntype, but in order both to fix the identity of the genus and species and to avert any possible dispute, it is here designated as neotype. Although it lacks the early whorls (remaining dimensions 6.5 x 2.5 mm), the specimen can be matched closely among samples from northern Mozambique .

Material examined from Indian Ocean : SOUTH YEMEN: Aden, neotype. N. MOZAMBIQUE: Lunga Bay , under rock slabs, on muddy sand and Thalassodendron, NMSA H 376, K. Grosch; Nacala, NMSA K9329 , don. Mrs H. Boswell; Conducia Bay, NMSA J4124 , K. Grosch. MASCARENES: Réunion Is., M. Jay; Gris Gris Beach, Mauritius, NMSA K9329 , R. Kilburn, D. Herbert .

Distribution: South Yemen and southern Red Sea, south to northern Mozambique and Mascarene Islands, and east (published records) to southern Japan and Polynesia.

Remarks: It was initially believed that Otitoma ottitoma ( Figs 2–8 ) could be recognized as a species distinct from O. cyclophora , based on comparison between a topotypic series of the latter ( Figs 9–13 ) and Mozambican samples that agree with the neotype of O. ottitoma . Thus in typical O. cyclophora the last whorl is somewhat less asymmetrical, the subsutural cord is more convex and bears a row of stronger tubercles, which crenulate or finely plicate the suture; beneath the sulcus is a corresponding row of more elongate tubercles, each pair joined by an arcuate axial riblet (representing an early anal sinus scar), which is indented by the sulcus. Spiral ridges are usually somewhat fewer (9–10 on penultimate whorl, against 6–9 in form ottitoma ) and more strongly granular. However, these differences are not always clear­cut and appear to represent populationlevel or geographic variation. The subsutural plicules are never as strong as illustrated by Deshayes (1863, see Figs 9–10 ).

The lectotype of Daphnella crenulata Pease, 1868 ( Fig. 14 ) is a juvenile with a broken lip, but resembles topotypes of O. cyclophora in similar condition.

Figures

Figs 2–8. Otitoma cyclophora (Deshayes, 1863). 2. Neotype of Otitoma ottitoma Jousseaume, 1898 [here designated], NMWC 1955.158.33.58, Aden; 6.5 x 2.5 mm. 3. Conducia Bay, Northern Mozambique, NMSA J4124, K. Grosch; 11.0 x 3.4 mm. 4–5. Lunga Bay, Northern Mozambique, inshore, under rock slabs on muddy sand, NMSA H376, K. Grosch; 10.6 x 3.5 mm. 6–8. ESEM, Conducia Bay, Northern Mozambique, NMSA J4124. 6. ESEM of sutural region of previous. 7. ESEM of protoconch, scale line = 200 mm. 8. ESEM of microshagreen sculpture on protoconch, scale line = 50 mm.

Figs 9–14. Otitoma cyclophora (Deshayes, 1863). 9–10. Type figures of Pleurotoma cyclophora (after Deshayes, 1863: pl. 12, figs 19, 21), Réunion Is. 11–12. Topotypes from Réunion Is., M. Jay, 8.0 x 2.4 mm and 6.3 x 2.3 mm (ESEM). 13. Protoconch and early whorls, scale­line = 500 mm. 14. Lectotype of Daphnella crenulata (designated Johnston, 1994), ANSP 15694, Polynesia [Howland Island, fide Johnston]; length 6.5 mm.