Phos pulchritudus, 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 : 160-163

Phos pulchritudus sp. nov.

urn:lsid:zoobank.org:act:2ECFAD36-9EB6-4BEC-A92C-3EF529AE9990

Figs 5 A–F, 9

Etymology

The specific epithet of Phos pulchritudus sp. nov. is derived from the Latin ʻ pulchritudo ʼ, meaning ʻbeautyʼ, ʻattractiveʼ, for the remarkable beauty of this shell.

Material examined

Holotype

MADAGASCAR • dd (28.6 mm long); off S Madagascar, ATIMO VATAE stn CP3622; 25°43.0′ S, 45°59.4′ E; depth 84–88 m; May 2010; ATIMO VATAE exped.; MNHN IM-2015-486 ( Figs 5 A–D, 9).

Paratypes

MADAGASCAR • 2 lv; S Madagascar, ATIMO VATAE CP3560 ; 25°37′ S, 46°10′ E; depth 102–106 m; May 2010; ATIMO VATAE exped.; paratypes 1–2; MNHN IM-2000-35088 • 1 dd; S Madagascar, off Narendry Bay , MIRIKY stn DW3237; 14°31′ S, 47°25′ E; depth 50–107 m; Jun. 2009; MIRIKY exped.; paratype 3; MNHN IM-2000-35089 .

MOZAMBIQUE • 1 lv; S Mozambique, S of Ponta Mucombo ; 26º18′ S, 33º00′ E; depth 87–90 m; Jan. 2018; J. Rosado leg.; dredge; paratype 4; JR • 1; S Mozambique, Ponta Abril ; 26º08′ S, 33º01′ E; depth 78–86 m; J. Rosado leg.; dredge; paratype 5; JR • 1; S Mozambique, S Quissico ; 25º08′ S, 34º43′ E; depth 105–135 m; J. Rosado leg.; trap; paratype 6; JR • 1 dd; S Mozambique, S of Inhambane, ex-pisces; depth 90–145 m; J. Rosado leg.; paratype 7; LR • 1 dd; S Mozambique, Zavora Point ; 24°36.7′ S, 35°22.0′ E, ex-pisces; depth 85–120 m; May 2009; J. Rosado leg.; paratype 8; JR • 2 dd; S Mozambique, NE Inhaca Island ; 25°49′ S, 33°07′ E; depth 87–94 m; Jan. 2016; J. Rosado leg.; dredge; paratypes 9–10; JR ( Fig. 5 E–F, paratype 10) • 1 d; S Mozambique, NE Inhaca Island ; 25°49′ S, 33°07′ E; depth 87–94 m; Nov. 2015; J. Rosado leg.; dredge; paratype 11; SG • 1 dd; S Mozambique, NE Inhaca Island ; 25°49′ S, 33°07′ E; depth 87–94 m; Nov. 2015; J. Rosado leg.; dredge; paratype 12 ; AS • 2; S Mozambique, Ponta Abril ; 26º08′ S, 33º01′ E; depth 78–86 m; J. Rosado leg.; dredge; paratypes 13–14; KF 8045 • 2; S Mozambique, NE Inhaca Island ; 25°49′ S, 33°07′ E; depth 92–96 m; J. Rosado leg.; dredge; paratypes 15–16; KF 7981 .

Description (holotype)

GENERAL. Shell of medium size, 28.6 mm in length, thin but solid ( Fig. 5 A–D). Shape fusiform with high spire; whorls rather convex; suture conspicious, accentuated by small notch formed where axial sculpture suddenly stops; base stretched. Colour and pattern rather bright. First 2 teleoconch whorls pinkish; last 4 teleoconch whorls pale yellowish, with 3 broad spiral bands. Subsutural spiral band pale brownish, darker on abapertural slope towards axial rib, paler or white on adapertural slope behind axial rib, but white when crossing a varix. Middle band pale, inconspicious, along penultimate whorl darker when crossing a varix. Suprasutural band along spire partly concealed under suture of subsequent whorl, along body whorl rather broad, occasionally interrupted, usually darker when crossing axial ribs or a varix. Those 3 spiral bands with some pink tinges in between. Spiral sculpture situated on those 3 spiral bands ornamented with interrupted lines of small brown specks, spiral sculpture situated in pale interspaces pale. Apertural varix with pink dots where those 3 spiral bands stop, adjacent anal notch and siphonal canal pink; inside aperture white to yellowish, with some pink tinges.

PROTOCONCH ( Fig. 5D ). Multispiral, tip chipped, with 3 remaining whorls, total of about 3½ whorls by estimation, 1.5 mm high, diameter 1.4 mm; colour usually pale yellowish with spiral cords of same colour. First remaining whorl well convex, smooth, glossy, with 1 spiral cord partly concealed under suture with subsequent whorl; this spiral cord becoming situated more adapically, thus above suture on second whorl; one additional sharp spiral cord appearing along second whorl; third whorl with 2 spiral cords, last 1 / 8 whorl with a few fine, opisthocline axial riblets adapically of those spiral cords. Transition to teleoconch marked by fine line followed by start of teleoconch sculpture.

TELEOCONCH. Consisting of about 6½ weakly convex whorls. First teleoconch whorl with 8 spiral cords of which 2 subsutural ones weak. Second whorl with 9 such spiral cords, third whorl with 12. An obscure secondary spiral thread, visible under magnificantion only, appearing in middle of some of those interspaces along third whorl. Spiral cords becoming weaker along fourth whorl. Penultimate whorl with up to 20 smooth spiral cords, adapical ones alternating fine and finer, abapical ones flattened, interspaces broad. Body whorl with about 37 such spiral cords, subsutural ones fine but somewhat more accentuated when crossing axial rib; along midwhorl flat, broad or absent; along base fine; near siphonal canal more accentuated to strong. Interspaces with an unequal amount of obscure secondary spiral threads, usually 1 or 3 in interspaces along subsutural slope and base, 5 in interspaces at midwhorl. First teleoconch whorl with 13 fine but sharp axial ribs including a few slightly stronger ones, interspaces of equal size. Second whorl with 15, third whorl with 17 similar axial ribs including up to 2 varices, interspaces growing slightly broader. Penultimate whorl with 19 axial ribs, including 1 varix. Body whorl with 19 axial ribs, including 1 varix and broad prelabral varix.

APERTURE. Columella concave, gently curved, with 2 columellar folds forming a moderately sharp angulation at transition to siphonal canal, parietal denticle small. Columellar callus thin, glossy, white but bright pink around anal notch and adjacent outer lip. Outer lip with about 38 thin but moderately sharp internal lirae, extending far into aperture, adapical ones alternating fine and finer. Outer lip thick, edge blunt, with strong notch along siphonal canal, colour white but with 3 bright pink dots according to pattern at outer surface, brightest at anal notch and at notch of siphonal canal. Aperture with siphonal canal slightly more than ⅓ of total shell length. Siphonal canal short, broad, open, on outside covered by fine spiral cords, colour white but with bright pink tip.

Distribution and habitat

Known from off the southern point of Madagascar in the south to Zavora (southern Mozambique) in the north ( Fig. 9 ).

Live collected specimens were taken at between 86 and 102 m, off Mozambique in a sponge reef area between 86 and 105 m, ex-pisces in the stomach of ʻCachucho fishʼ ( Polysteganus coeruleopunctatus (Klunzinger,1870)) and ʻMarreco fishʼ ( Chrysoblephus puniceus (Gilchrist & Thompson,1908)) fished at depths between 85 and 120 m.

Remarks

Phos pulchritudus sp. nov. is characterized by its rather slender shell with a slightly stretched base, weak sculpture and glossy surface, and the three broad darker bands and fine interrupted spiral lines; typical specimens show peculiar pink dots at the aperture and siphonal canal.

The harmonious combination of these features makes the shells of this species an outstanding piece of visual beauty.

Variability is moderately high. The shell is usually between 22 and 25 mm in length but occasionally up to 28.6 mm (holotype). Paratype 3, for example, is smaller than the holotype and differs in its lower number of teleoconch whorls (5½ instead of 6½). This specimen is not as slender as the holotype and on the first teleoconch whorl the abapical spiral cord (the 6 th cord) is still concealed under the suture of the subsequent whorl, while on the second whorl the same happens with the 7 th spiral cord; this is in combination with only a single fine spiral cord being present along the subsutural slope (instead of 2). This makes the number of spiral cords quite different. This specimen is also smoother than the holotype, with an obscure spiral sculpture, resulting in a number of spiral cords along the teleoconch and body whorl that is difficult to count. The internal lirae within the upper part of the outer lip (adapical) may be alternating fine and finer (see holotype) or of equal strength (paratype 1).

A number of similar looking shells, but with a white aperture including a white outer lip, lack the typical pink dots ( Fig. 5 G–H). It is still uncertain whether this morph is conspecific with the new species and we therefore record it tentatively as Phos cf. pulchritudus sp. nov.

Phos idyllium ( Fraussen & Poppe, 2005) from the Philippines has a very similar sculpture and pattern, especially the pink tip of the siphonal canal. It differs, however, from P. pulchritudus sp. nov in its larger protoconch (diameter up to 1.7 mm), the surface of the shell, which is even more glossy, the suture, which is accentuated (by a small notch formed where the axial sculpture suddenly stops) along the last part of the body whorl only and at the prelabral varix, the higher number of axial ribs (up to 17 on the first teleoconch whorl, 18–20 on the second and 20–25 on the penultimate and body whorls) and the usually paler protoconch.

Figures

Fig. 5. Phos pulchritudus sp. nov. A–C. Holotype, S Madagascar, ATIMO VATAE stn CP3622, 25°43.0′ E, 45°59.4′ E, depth 84–88 m, 28.6 mm long (MNHN IM-2015-486). D. Apex of holotype. E–F. Paratype 10, S Mozambique, NE Inhaca Island, 25°49′ S, 33°07′ E, dredged at 87–94 m, 25.3 mm long (JR). G–H. Phos cf. pulchritudus, Mozambique, off Zafora, 24 mm long (JR). Scale bars: A–C, E–H = 5.0 mm; D = 0.1 mm.

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