Phos ladoboides, Fraussen & Galindo & Rosado, 2020

Fraussen, Koen, Galindo, Lee Ann & Rosado, José, 2020, Deep-water Photinae (Gastropoda: Nassariidae) from eastern Africa, with descriptions of five new species, European Journal of Taxonomy 720, pp. 144-169 : 157-159

Phos ladoboides sp. nov.

urn:lsid:zoobank.org:act:D4C1306E-9F13-48A5-B45B-EB3840539538

Figs 4 , 9

Etymology

Phos ladoboides sp. nov. is named after the local dish, ‘ladob’, the contemporary desert version made from plantain (a kind of banana) and sweet potatoes with coconut milk, nutmeg and vanilla or sugar. The colour of the shell, often yellowish as a banana, often brownish-range as some sweet potatoes, with brown dots like nutmeg or with white bands or white axial ribs like coconut milk and vanilla or sugar, remind us of this dish.

Material examined

Holotype

SEYCHELLES • lv (22.4 mm long); REVES-2 stn 31; 04°36′ S, 54°20′ E; depth 38 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN IM-2015-482 ( Figs 4 A–C, 9).

Paratypes

SEYCHELLES • 8 lv; same collection data as for holotype; paratypes 1–8; MNHN IM-2000-28504 ( Fig. 4 D–E, paratype 1) • 1 lv; same collection data as for holotype; paratype 9; JR • 3 lv; off Mahé; deep water; 2010; crayfish trap; paratypes 10–12; KF 6126 ( Fig. 4 F–J) • 5 dd; Mahé; 1967; paratypes 13–17; KF 0455 .

Other material

MAURITIUS • 1 dd; St. Brandon, St. Brandon Shoal, in coral rubble; shallow water; 2014; F. Lorenz leg.; KF 7980 .

SEYCHELLES • 5 dd; off Mahé; 1967; old collection; KF 0455 • 3 lv; off Mahé; deep water; 2010; crayfish traps; KF 6126 . – REVES-2 Exped. • 5 lv, 1 dd; stn 5; 05°05′ S, 56°24′ E; depth 33 m; Aug.– Sep. 1980; REVES-2 exped.; MNHN • 1 lv (jv); stn 6; 04°59′ S, 56°13′ E; depth 40 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 1 lv; stn 13; 05°20′ S, 56°20′ E; depth 53 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 3 dd; stn 26; 04°57′ S, 55°11′ E; depth 63 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 1 dd; stn 29; 04°43′ S, 54°37′ E; depth 50 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 14 lv, 2 dd; stn 31; 04°36′ S, 54°20′ E; depth 38 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 5 dd (3 jv); stn 37; 04°35′ S, 55°12′ E; depth 65 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 1 lv; stn 39; 04°50′ S, 56°35′ E; depth 45 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 1 dd; stn 54; 03°53′ S, 55°10′ E; depth 50 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 1 dd; stn 58; 04°11′ S, 54°39′ E; depth 60 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 3 dd; stn 60; 04°10′ S, 55°12′ E; depth 46 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN • 1 lv; stn 62; 04°10′ S, 55°25′ E; depth 68 m; Aug.–Sep. 1980; REVES-2 exped.; MNHN .

Description (holotype)

GENERAL. Shell of medium size for the genus, 22.4 mm in length. Shape fusiform with moderately high spire. Colour yellowish brown, primary spiral cords off-white to white ( Fig. 4 A–C).

PROTOCONCH. Large, multispiral, consisting of 4 whorls; eroded, tip chipped, 3½ whorls remaining but number of whorls countable; diameter 1.6 mm, remaining whorls 1.7 mm in length, diameter 1.6 mm. First whorl convex, smooth, glossy. A single, fine but sharp spiral cord appearing along second whorl. A second spiral cord appearing along third whorl. Last ½ part of last protoconch whorl with 3 fine but sharp spiral cords and several strongly opisthocline axial ribs that become well pronounced. Transition to teleoconch marked by pronounced opisthocline rib followed by start of teleoconch sculpture.

TELEOCONCH. Consists of about 5½ rather convex whorls. Sculpture rather reticulate, with fine spiral cords that form a sharp knob when crossing otherwise rather smooth axial ribs. First teleoconch whorl ornamented with 6 fine primary spiral cords, including 2 finer ones along subsutural slope; interspaces broad, starting with a single fine secondary thread but suddenly increasing to 3. Strength of primary spiral cords increasing along second whorl. Third whorl with 6 rather fine but sharp primary spiral cords; interspaces broad with 3 secondary spiral cords of which central one slightly stronger. Number of secondary spiral cords increasing to 5 in middle interspace only. Primary spiral cords slightly broader along penultimate whorl, occasionally slightly flatter. Body whorl with 13 moderately broad, slightly flattened spiral cords, including 2 slightly finer ones along subsutural slope; interspaces broad, with 3 fine secondary spiral cords (5 in middle interspace); subsutural interspaces narrow. First teleoconch whorl with about 12 sharp axial ribs, including 1 white varix. Number of axial ribs only slightly increasing up to 14 along other whorls, including 2 (on penultimate whorl) or 3 (on other whorls) varices. Body whorl with 14 axial ribs, including 1 varix; apertural varix large, broad.

APERTURE. Semi-ovate; white, outer lip occasionally with narrow brownish border according to pattern of outer surface. Outer lip with 12 fine but sharp internal lirae. Columella with 2 moderately strong columellar folds at transition to siphonal canal. Lip thin, edge sharp, without siphonal notch. Siphonal canal open, broad, short, typical of the genus.

Distribution and habitat

Known from deep water off the Seychelles Archipelago and a single specimen from St. Brandon ( Fig. 9 ).

Syntopic with P. geminus sp. nov. (REVES-2 stn 5, KF 7866).

Remarks

Phos ladoboides sp. nov. is characterized by its rather broad shape with a short spire, the sharp, reticulate sculpture, the rather large protoconch and the banded pattern. The shell is of medium size for the genus (up to 25.2 mm in length, usually between 19 and 23 mm).

The colour is highly variable, ranging from white ( Fig. 4H ), over yellowish and uniform orange-brown to dark brown with a pattern of broad bands. When patterned ( Fig. 4 F–G), then with a single broad, brown to dark brown spiral band along the spire whorls, this broad band often becoming much finer along the body whorl; body whorl usually with 3 brown to dark brown spiral bands, the band along the base being the broadest, occasionally with one of those bands missing; occasionally with a narrow brown subsutural spiral band which suddenly ends in a white dot before the prelabral varix.

The spiral sculpture shows little variation. The first teleoconch whorl is usually ornamented with 6 fine primary spiral cords (see the holotype), occasionally with 7 (see paratype 2). The third whorl has 6 (holotype) or 7 (paratypes 1–2) rather fine but sharp primary spiral cords. The interspaces are broad, with 3 secondary spiral cords of which the central one is slightly stronger. The interspace situated at the middle of the whorl usually has 5 instead of 3 such secondary spiral cords, an increase that may start along the 3 rd teleoconch whorl (see holotype) or along the penultimate whorl (see paratype 1). The number of axial ribs varies only slightly, from 13 (paratype 1) to 14 (holotype).

Phos geminus sp. nov. differs from P. ladoboides sp. nov. by its slender shape with a higher spire, the somewhat stretched base, the lower number of spiral cords in combination with a higher number of axial ribs, the usually more uniform colour and the usually larger adult size.

Phos verbinneni (Fraussen, 2009) from the Philippines looks identical in sculpture and pattern but differs from P. ladoboides sp. nov. by its slightly larger protoconch in combination with a lower number of teleoconch whorls (slightly more than 4½ instead of 5½–6 for shells of about the same size), the transition to the teleoconch that is marked by a straight rib (instead of a strongly opisthocline one), the slightly higher number of spiral cords along the penultimate whorl (8 instead of 6–7) and the slightly higher number of axial ribs. Only a single specimen of P. verbinneni is known at the present and therefore no information about variabity within that species is known.

Figures

Fig. 4. Phos ladoboides sp. nov. A–C. Holotype, Seychelles, REVES-2 stn 31, 04°36′ S, 54°20′ E, depth 38 m, 22.4 mm long (MNHN IM-2015-482). D–E. Paratype 1, same collection data as for holotype, 15.3 mm long (MNHN IM-2000-28504). F–G. Paratype 11, Seychelles, off Mahé, in crayfish trap, deep water, 24.0 mm long (KF 6126). H. Paratype 12, same collection data as for preceding, 25.2 mm long (KF 6126). I–J. Paratype 10, same collection data as for preceding, 23.5 mm long (KF 6126). Scale bars: 5.0 mm.

Fig. 9. Distribution of Phos ladoboides sp. nov., P. pulchritudus sp. nov. and P. testaceus sp. nov.