Obtusopyrgus farri Verhaegen & Haase 2021, sp. nov.

Obtusopyrgus farri sp. nov.

urn:lsid:zoobank.org:act: 2D7008F8-BB41-448D-94AF-969925CECDAB

Figs 4 I–J, 5 H–I, 6 F, 8 D, 11 D, 14; Tables 1 – 2

Diagnosis

In the new species, the central tooth of the radula has more cusps on the edge and less on the basis than in the only other known representative of the genus, Ob. alpinus. The bursa copulatrix is smaller and more elongate compared to the larger, more globular one in the latter. As a consequence, the seminal receptacle reaches far behind the bursa in Ob. farri sp. nov., whereas in Ob. alpinus it lies entirely against the bursa. These species differ at five diagnostic alignment positions of type 1.

Etymology

Obtusopyrgus farri sp. nov. is named after Gareth Farr, acclaimed New Zealand percussionist and composer integrating non-European music styles including Maori music into Western classical music resulting in the most fascinating and colorful synthesis of different musical expressions. His alter ego, the drag queen Lilith LaCroix, is also colorful.

Material examined

Holotype (Fig. 4I) NEW ZEALAND • Nelson Lakes National Park, Lake Rotoiti, small stream crossing Lakeside Track close to lake shore; 41°49ʹ30.7ʺ S, 172°49ʹ50.1ʺ E; 13 Mar. 2016; G. Verhaegen and M. Haase leg.; on leaves, stones, woody debris in small stream crossing track; NMNZ.M.330195.

Paratypes (Figs 4J; 5 H–I) NEW ZEALAND • 21 specs; same collection data as for holotype; NMNZ.M.330196.

Description

SHELL (Figs 4 I–J, 5H–I). Blunt-ovate to pupiform, about 1.7 times as high as than wide, light brown, translucent with brown periostracum; protoconch almost smooth, comprising up to 1 whorl (Fig. 6F); entire shell with 3.625 to 4.25 whorls, teleoconch initially with very fine longitudinal ridges, then without structure apart from growth lines; umbilicus narrow; aperture orthocline, as high as wide.

OPERCULUM. Yellow to light orange, paucispiral; nucleus submarginal, without peg.

EXTERNAL FEATURES (Figs 4 I–J). Epidermis with irregular, large pigment blotches; eyes well developed and entirely pigmented; tentacles without particular ciliation.

MANTLE CAVITY (n = 4). 8–11 ctenidial filaments; osphradium ovate-elongate, behind middle of gill.

DIGESTIVE SYSTEM. Radula has formula R 5 1 5/2–3 2-3, L 5–7 1 5–7, M1 23–28, M2 25–28 (Fig. 8D); stomach without caecum; rectal loop pointing left in roof of mantle cavity, in males more distinct than in females.

FEMALE GENITALIA (n = 4; Fig. 14). Ovary lobate sac starting> 1.5 whorls below apex, comprising ca 0.3 whorl and not reaching stomach; renal oviduct first coiling 180° clockwise, then 270° counterclockwise; one distal, large receptaculum seminis reaching far behind bursa copulatrix; bursa copulatrix an elongate sac lying behind albumen gland, bursal duct entering anteriorly; ovoviviparous, brooding at least three embryos in pallial oviduct, pallial oviduct as brood pouch, albumen gland has about third of length of capsule gland, the latter histologically uniform in CT scans.

MALE GENITALIA (n = 1). Testis lobate sac, starting ca 1 whorl below apex, comprising up to 1 whorl, reaching stomach; vesicula seminalis coils along anterior half of testis; proximal vas deferens inserts close to middle of kidney-shaped prostate, distal vas deferens leaving anteriorly; penis massive, broad, short, pointed tip, without appendages (Fig. 11D).

Remarks

The new species is slightly larger than Ob. alpinus (shell height: Mann-Whitney U-test: z = 2.869, p = 0.004), but in terms of shape, they cannot be distinguished (shell height/shell width: Mann-Whitney U-test: z = 0.764, p = 0.445). The genetic and phylogenetic distinction of both species of Obtusopyrgus was only based on 16S as sequencing of COI failed (Fig. 2). There were five diagnostic characters (Table 2). The well-developed eyes indicate that Ob. farri sp. nov. inhabits epigean waters.