Favartia (Pygmaepterys) lifouensis, Houart & Héros, 2012

Houart, Roland & Héros, Virginie, 2012, New species of Muricidae (Gastropoda) and additional or noteworthy records from the western Pacific, Zoosystema 34 (1), pp. 21-37 : 23-24

Favartia (Pygmaepterys) lifouensis n. sp. ( Fig. 1 A-D, K, L)

TYPE MATERIAL. — Holotype (dd) MNHN 24174 ; 5 paratypes (dd) MNHN 24175-24177 ; 1 paratype (dd) coll. RH.

MATERIAL EXAMINED. — New Caledonia. ATELIER LIFOU 2000: stn 1423, Loyalty Islands, Lifou, Baie du Santal, off Peng, 20°54’S, 167°07’E, 12 m, 1 dd, paratype MNHN 24175. — Stn 1442, Lifou, Baie du Santal, Aimé Martin Cape, 20°46’S, 167°02’E, 47 m, 1 dd, paratype coll. RH. — Stn 1445, Lifou, east of Baie du Santal, 20°51’S, 167°10’E, 10-12 m, 1 dd, paratype MNHN 24176. — Stn 1461, Lifou, Baie du Santal, Shelter Reef, 20°54’S, 167°02’E, 100-120 m, 1 dd, holotype MNHN 24174. — BATHUS 1: stn DW692, east coast, 20°35’S, 164°59’E, 140-150 m, 3 dd, paratypes MNHN 24177. Solomon Islands. SALOMONBOA 3: stn DW2840, W San Cristobal, 10°25’S, 161°22’E, 121-180 m, 1 dd, MNHN. — Stn DW2841, 10°26’S, 161°23’E, 142- 160 m, 1 dd, MNHN.

TYPE LOCALITY. — Loyalty Islands, Lifou, Baie du Santal, Récif Shelter, 20°54’S, 167°02’E, 100-120 m [ ATELIER LIFOU 2000: stn 1461].

DISTRIBUTION. — Currently known from New Caledonia, probably living in 10-47 m and from W San Cristobal, Solomon Islands, dredged dead in 12- 142 m.

DESCRIPTION

Shell large for the subgenus, height up to 11.5 mm at maturity,height/width ratio1.7-2.0.Slender,biconical, broadly-ovate, squamous. Subsutural ramp narrow, weakly sloping, weakly concave. Shell white or light tan, occasionally darker coloured P5 or from P5 to tip of siphonal canal, with light brown blotches on subsutural area and above anal notch.Aperture white. Spire high with 1.5 protoconch whorls ( Fig.1K, L) and up to five broadly convex, weakly angulate, shouldered whorls. Suture of teleoconch whorls adpressed.Protoconch large, broad, whorls rounded. Diameter of protoconch (holotype) 700 µm. Terminal lip thin, weakly raised, almost straight.

Axial sculpture of teleoconch whorls consisting of moderately high, narrow, webbed varices. First whorl with 6 or 7 varices, second to penultimate with 5 or 6, last whorl with 5 varices. Other axial sculpture of numerous, low, obvious growth lamellae. Spiral sculpture of low, broad, squamous primary cords and narrow, squamous, occasionally shallow secondary cords and threads. First teleoconch whorl with visible P1 and P2, P1 weaker; 2nd whorl with P1, s1, P2; 3rd with adis, IP, abis, P1, s1, P2, (P3), s1 similar in strength to P1; 4th whorl of subadult paratypes with adis, IP, abis, P1, s1, P2, P3, P4, (s4), P5, (s5), P6, s6, ADP, MP, ABP; last whorl of holotype with adis, IP, abis, P1, s1, P2, P3, P4, P5, P6, ADP, MP, ABP, ads and two or three additional abapical threads; s1 broader than P1, P2-P4 broadest, P5 and next cords decreasing in strength abapically. Presence of several narrow, squamous threads between and on spiral cords. Spiral cords extending on axial varices, forming webbed varices.

Aperture moderately large, narrow, ovate.Columellar lip narrow, with 2 or 3 small denticles abapically; abapical two denticles closely spaced. Rim partially weakly erect, adherent at adapical extremity, with weak or obsolete, low parietal tooth at adapical extremity. Anal notch deep, narrow. Outer lip weakly erect, crenulated, with strong, broad denticles within: ID, D1 (occasionally split), D2-D5. Siphonal canal medium sized, broad, weakly dorsally recurved, open.

Operculum and radula unknown.

REMARKS

There are 14 species of Pygmaepterys in the tropical Indo-West Pacific. Three of them have only three axial varices on the last teleoconch whorl, two other species are very small and are geographically restricted to South Africa, while another three species live in the vicinity of the Gulf of Aden and Oman. These eight species do not need to be discussed further here because of their very different shell morphology.

Favartia funafutiensis (Hedley, 1899) has a different protoconch morphology, in that it is conical with 2+ whorls, and weakly and narrowly keeled abapically.

The five remaining species are F. avatea Houart & Tröndlé, 2008 , F. bellini (D’Attilio & Myers, 1985) , F. isabelae Houart & Rosado, 2008 , F. kurodai Nakamigawa & Habe, 1961 and F. philcloveri (Houart, 1984) .

Favartia lifouensis n. sp. differs from F. avatea ( Fig. 1E, F) in having a more strongly shouldered shell with a more weakly sloping subsutural area, a higher and narrower spire, a comparatively broader protoconch, an adpressed suture instead of the impressed one in F. avatea , fewer axial varices, 5 on the last whorl and 6 or 7 on previous whorls in P. lifouensis vs 6 on the last whorl and 7-9 on previous whorls in F. avatea , and weaker, more numerous apertural denticles.

It differs from F. bellini ( Fig. 1G, H) in having a less shouldered and more ovate shell, narrower, more conspicuous and higher spiral cords and a comparatively broader aperture with smaller denticles.

Favartia isabelae , F. kurodai and F. philcloveri also differ in many ways, including shell height and width, and protoconch, spiral sculpture and aperture morphology.