Leiorhagium aremuum, Haase, Martin & Zielske, Susan, 2015

Haase, Martin & Zielske, Susan, 2015, Five new cryptic freshwater gastropod species from New Caledonia (Caenogastropoda, Truncatelloidea, Tateidae), ZooKeys 523, pp. 63-87 : 68-70

Taxon classification Animalia Littorinimorpha Tateidae

Leiorhagium aremuum sp. n.

Type material.

Holotype MNHN IM 2000-27862; paratypes MNHN IM 2000-27863 (28), NHMW 110184 (10).

Type locality.

NeCa 33, Moindou: spring-fed stream close to road in Aremu valley, under shrub, 21°35'04.8"S, 165°39'07.5"E, 26 May 2012.

Etymology.

The new species is named after the Aremu valley, where it has been discovered.

Diagnosis.

Leiorhagium aremuum sp. n. is most similar to Leiorhagium ajie , which is, however, larger and slightly more slender, lacks the palatal denticle, and has a more massive penis. The prolonged capsule gland is unique among New Caledonian tateids. The COI sequences had a p-distance of 9.4%.

Shell.

Broadly pupiform, 1.62 times higher than wide, 3.75-4.25 whorls, without colour, transparent; protoconch faintly pitted with 0.75-0.9 whorls; palatal denticle a small droplet 1/8 whorl behind outer lip; aperture practically as high as wide (Figs 2C, 3E,F, 4E,F).

Operculum.

Elongate-ellipsoidal, paucisprial, nucleus submarginal, orange, two non-calcareous white pegs, eventually accompanied by a small third one (N=4) (Fig. 5E, F).

External features.

Epidermis without pigment, eyes black.

Mantle cavity.

Ctenidium with 15-16 (2 males) or 19-20 (2 females) filaments; osphradium elongate, slightly behind middle of ctenidium.

Digestive system.

Radula formula (N=3) (Fig. 6C): R: 4-5 1 4-5/2-3 2-3, L: 4-5 1 4-6, M1: 26-31, M2: 20-32; stomach without caecum; rectum close to pallial oviduct in females, with short loop left of prostate in males.

Female genitalia.

Ovary without lobes, proximal end 1.25-1.75 whorls below apex, comprising 0.25-0.5 whorls, reaching stomach; capsule gland with long and slender, opaque-white vestibulum, anterior capsule gland yellow-orange, toward posterior capsule gland covered with brown spots, posterior capsule gland opaque-white with a central milky section, albumen gland milky-white; proximal loop of renal oviduct bent forward, distal loop long; bursa copulatrix higher than long, reaching behind albumen gland; bursal duct long, entering anterior; no seminal receptacle (N=3) (Fig. 7C).

Male genitalia.

Proximal end of lobate testis 1 whorl below apex, comprising c. 0.75 whorls, covering proximal end of stomach; vesicula seminalis arising from distal third of testis; penis very long and slender (N=2) (Fig. 8D).

Remarks.

This is Leiorhagium sp. n. 3 of Zielske and Haase (2015). Leiorhagium aremuum sp. n. is only known from the type locality.