Phos ganii, 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 : 150-153

Phos ganii sp. nov.

urn:lsid:zoobank.org:act:CADD5662-D4B1-4160-B2DE-ED8D470BF685

Figs 2 , 8

Etymology

Phos ganii sp. nov. is named to honour the late Gani Satar for his contributions to malacology, as he was one of the very first people who collected Mozambican shells. Gani passed away on April 19, 1998 in Mozambique.

Material examined

Holotype

MOZAMBIQUE • dd (27.2 mm); Mozambique Channel , Maputo transect, near Maputo, MAINBAZA stn CP3143; 23°32′ S, 35°46′ E; 264–277 m; Apr. 2009; MAINBAZA exped.; MNHN IM-2015-485 ( Figs 2 A–D, 8).

Paratypes

MADAGASCAR • 3 dd; Mozambique Channel, off Majenga; on Xenophora pallidula (Reeve, 1842) , trawled in deep water; 2000; local fishermen leg.; paratypes 11–13; KF 2556 ( Fig. 2 K ) • 2 dd; same locality as for preceding; on Xenophora pallidula ; 2000; local fishermen leg.; paratypes 14–15; KF 5236 • 1 dd; from old collection; paratype 16; KF 7702 .

MOZAMBIQUE • 1 dd; same collection data as for holotype; paratype 1; MNHN IM-2000-35085 ( Fig. 2 E–G) • 2 dd; S Mozambique, off Maputo; on Xenophora pallidula ; depth 150–350 m; local fishermen leg.; trawl; paratypes 2–3; KF 5419 • 1 dd; S Mozambique, off Massinga ; 23°32′ S, 35°47′ E; 270–320 m; Nov. 2005; J. Rosado leg.; trawl; paratype 4; JR .

TANZANIA • 3 lv; S Tanzania, off North Rovuma River ; 7°24′ S, 39°51′ E; depth 330–360; Nov. 2005; Portuguese fishery vessel; trawl; paratypes 5–7; JR (paratype 5, Fig. 2H ; paratype 6, Fig. 2 I–J) • 3 dd; same collection data as for preceding; on Xenophora pallidula ; paratypes 8–10; JR .

Other material

MOZAMBIQUE • 1 fragment; off Maputo; on Xenophora pallidula ; depth 150–350 m; local fishermen leg.; lot also contains paratypes 2–3; trawl; KF 5419 .

Description (holotype)

GENERAL. Shell rather small for the genus, 27.2 mm in length. Shape broadly fusiform with moderately high spire, base stretched, giving a biconical appearance. Suture rather deep, accentuated by narrow, flattened shoulder of subsequent whorl. Sculpture cancellate, forming knobs where fine spiral sculpture crosses broader axial ribs. Colour white or yellowish to pale brown, spiral cords often brown ( Fig. 2 A–C).

PROTOCONCH ( Fig. 2D ). Multispiral, tip chipped, with 3 remaining whorls, total of about 3¾ whorls by estimation, 1.0 mm high, diameter 1.0 mm; white with spiral cords of same colour, with 1 spiral cord initially concealed under suture with subsequent whorl, appearing on last half; second whorl with fine but sharp spiral cord, suprasuturally situated; this spiral cord more adapically situated along third whorl, with a second spiral cord appearing from below suture with subsequent whorl; last whorl with 3 such spiral cords, its last ¼ part with a few fine, opisthocline axial riblets adapically of those spiral cords. Transition to teleoconch marked by fine line and start of teleoconch sculpture.

TELEOCONCH. Consisting of 6½ weakly convex whorls. First teleoconch whorl starting with 6 fine spiral cords of which subsutural one weaker, their strength gradually increasing, with 1 fine secondary spiral thread appearing in interspaces. Second whorl with 6 such spiral cords, interspaces with 3 fine secondary spiral cords. Third whorl with 6 strong primary spiral cords, interspaces starting with 3 (in abapical interspaces) to 5 (in adapical interspaces) secondary spiral cords. Primary spiral cords gradually more pronounced along spire, but their number remaining constant. Penultimate whorl with 6 moderately large primary spiral cords; interspaces broad, with 3 (in abapical interspaces) to 5 (in adapical interspaces) secondary spiral cords (these cords quite difficult to count with precision). Body whorl with 15 spiral cords, 6 abapical ones moderately large with broad interspaces, on base only slightly weaker, with narrower interspaces with 1–3 fine secondary spiral cords.

APERTURE. Large, semi-oval but rather narrow for genus, adapically weakly pinched. Columella with 2 strong columellar folds. Parietal part straight. Adapical border of aperture broad, formed by shoulder of body whorl. Outer lip thick, with 13 or 14 thin but moderately sharp internal lirae, extending far into aperture; edge sharp. Aperture with siphonal canal more than 2 / 5 of total shell length. Siphonal canal rather long for genus, broad, open, covered by fine spiral cords on outside.

Distribution and habitat

Known from deep water in Mozambique Channel ( Mozambique and Madagascar) in the south to southern Tanzania in the north ( Fig. 8 ).

Live-collected specimens were found at between 330 and 360 m in Tanzania and empty shells between about 264 and 800 m.

The species is found attached to Xenophora pallidula quite frequently and according to our observations more often than for other deep-water Nassariidae and Buccinidae . Besides being a useful secondary collecting method (Terryn 2008: 1–4) this also may throw some light on habitat characteristics.

Remarks

Phos ganii sp. nov. is characterized by its somewhat biconical shape and deep suture, the usually constant number of 6 primary spiral cords, the moderately large knobs, formed where spiral and axial sculptures cross, and by the rather narrow aperture with moderately long siphonal canal. The shape is reminiscent of that in the Carribean genus Antillophos ( Galindo et al. 2016) in outline and sculpture.

The colour is usually white or yellowish to pale brown (see holotype), while fresh specimens (paratypes 5, 7, 11–13, 16) may be slightly darker with 3 broad but only slightly darker spiral bands.

The number of fine secondary spiral cords on the base is usually 1–3, in some paratypes they occasionally grow up to 4.

Variability in sculpture is low while size may vary considerably; paratypes 5–7 (22.8–25.1 mm) have 6 to 6½ whorls, paratypes 11–13 (21.3–23.2 mm) are only slightly smaller but have about 5½ whorls.

Phos durianoides ( Fraussen & Poppe, 2005) looks similar but differs from P. ganii sp. nov. by its rather semi-oval shape, the strong knobs where spiral and axial sculptures cross and the broad secondary spiral cords with a fine groove as interspace.

Phos gemmulifer Kilburn, 2000 ( Fig. 1 D–E) differs from P. ganii sp. nov. by its broader shape, thicker shell, larger knobs and larger size.

Phos retecosus Hinds, 1844 (type locality: “ Ceylon ”) differs from P. ganii sp. nov. by its broader shape, the smoother subsutural area, the presence of brown lines on top of the spiral cords and some brownish bands on the body whorl and on the labral varix. The size is slightly larger.

Figures

Fig. 2. Phos ganii sp. nov. A–C. Holotype, Mozambique Channel, Maputo transect, MAINBAZA stn CP3143, 23°32′ S, 35°46′ E, depth 264–277 m, 27.2 mm long (MNHN IM-2015-485). D. Apex of holotype. E–F. Paratype 1, same collection data as for holotype, 29.3 mm long (MNHN IM-2000- 35085). G. Protoconch of paratype 1. H. Paratype 5, S Tanzania, off North Rovuma River, 7°24′ S, 39°51′ E, trawled by Portuguese fishery vessel, depth 330–360 m, 22.8 mm long (JR). I–J. Paratype 6, same collection data as for preceding, 23.4 mm long (JR). K. Paratypes 11–13, Madagascar, Mozambique Channel, off Majenga, trawled in deep water, on Xenophora pallidula (Reeve, 1842) (KF 2556). Scale bars: A–C, E–F, H–K = 5.0 mm; D, G = 1.0 mm.

Fig. 8. Distribution of Phos ganii sp. nov. and P. geminus sp. nov.

Fig. 1. A–C. Phos elegantissimus Hayashi & Habe, 1965. A–B. Specimen from Mozambique, off North Quissico, depth 95–135 m, in trap, 23.8 mm long (JR). C. Specimen from Mozambique, off Sofala Bank, ex-pisces, depth 120–140 m, 24.8 mm long (JR). — D–E. Phos gemmulifer Kilburn, 2000, NW Mayotte, Mozambique Channel, BIOMAGLO stn DW4848, 12°35′ S, 44°55′ E, depth 399–402 m, 28.1 mm long (MNHN 2013-69815). — F–I. Phos hirasei G.B. Sowerby III, 1913. F–G. Specimen from Mozambique, off Sofala Bank, 20°07′ S, 36°09′ E, ex-pisces, depth 120–130 m, 26.3 mm long (JR). H–I. Specimen from South Africa, off Transkei, Msikaba, dredged at 90–110 m, 25.7 mm long (KF 4692). — J–K. Phos laevis Kuroda & Habe, 1961, Madagascar, Campagne CREVETTIERE 1974 stn DC01, 12°39′ S, 48°16′ E, depth 240 m, 23.5 mm long (MNHN). Scale bars: 5.0 mm.