Eulodrobia fenshami Zhang 2019, n. sp.
Creators: name: Zhang, - H.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Tateidae
Eulodrobia
Eulodrobia fenshami

description: Eulodrobia fenshami n. sp.
Material examined. Holotype: Queensland, spring W side of Paroo R, near Eulo township, 28° 09' 30" S, 145° 02' 10" E, small seeping mound amongst trees, snails in and on mud (some out of water), mostly under grasses in midsection of mound, W.F. Ponder, J.H. Waterhouse & A.C. Miller, 6 Apr 2002, C.479950. Paratypes: Same data, C.410721, 20+, C.431170, 20+; QM MO85761, 5.
Shell (Fig. 2A, 3A). Ovate, spire outline moderately convex, normally coiled, opaque. Length 1.7–2.5 mm (mean 2.1 mm), width 1.8–2.3 mm (mean 2.1 mm). Protoconch of 1.2 to 1.3 whorls, irregularly minutely pitted (Fig. 3A). Teleoconch whorls moderately convex, evenly rounded, total number 3.0–4.1 (mean 3.8). Umbilicus moderately wide. Sculpture of axial growth lines only. Aperture ovate, inner lip narrow, thick, slightly separated along whole length of parietal wall, outer lip medium. Periostracum moderately developed, yellow-brown or black or reddish-brown.
Operculum (Fig. 4A, B). Transparent, pale yellow or yellow-brown, slightly concave, nucleus acentric. Inner side lacking white smear, simple.
Head-foot and external body. Snout, tentacles, neck and opercular lobes pigmented, dorsal and lateral foot unpigmented, mantle roof weakly pigmented to black, visceral coil weakly to densely pigmented.
Mantle cavity. Ctenidium well-developed, filaments 17–19, broadly triangular, apex towards right. Osphradium narrowly oval, towards posterior end of ctenidium, length relative to gill 0.32–0.45. Hypobranchial gland thin (poorly developed). Rectum with U-shaped bend, faecal pellets orientated obliquely and longitudinally or orientated obliquely or sideways, anus behind mantle collar. Kidney extends for about quarter of length into mantle cavity roof. Renal gland transverse. Pericardium extends for about quarter of length into mantle cavity roof, abutting posterior end of ctenidium.
Radula (Fig. 5A, B). Central teeth with cusp formula 2–4+1+2–3, basal cusps 2+2; median cusp narrow, sharp, about twice as long as adjacent cusps. Lateral teeth with cusp formula 2–3+1+3, main cusp pointed, slightly curved, less than twice as long as adjacent cusps. Inner marginal teeth with 13–18 cusps. Outer marginal teeth with 22–28 cusps.
Female reproductive system (Fig. 6A, B). Ovary weakly lobed. Renal oviduct makes wide, open loop over bursa copulatrix. Seminal receptacle oval, duct very short; opens to renal oviduct opposite anterior end of bursa; orientated sperm also in renal oviduct. Bursa copulatrix behind albumen gland, pyriform, about same length as albumen gland, bursal duct enters bursa mid anteriorly, bursal duct joins coiled oviduct in front of posterior mantle cavity wall. Albumen gland partly in mantle cavity. Capsule gland with two distinct glandular zones, medium thickness in cross section, markedly indented by rectum. Anterior vestibule small, opening anterior to capsule gland, short.
Male reproductive system (Figs. 7A, 8A). Prostate gland less than half in mantle roof, bean-shaped, medium in cross section. Posterior and anterior pallial vas deferens slightly undulating. Penis towards middle of head, intermediate, distal end with non-glandular lobe, terminal papilla absent.
Etymology. Named for Dr. Rod Fensham, who originally discovered this species.
Distribution and habitat. Known from a single small muddy spring on the edge of the western side of the Paroo River (Paroo River Springs in Commonwealth of Australia 2014) in the town common near the township of Eulo, SW Queensland (Fig. 1). This small spring was vegetated with sedges and ‘grass’ and shaded by trees.
Remarks. This species is most similar to Eu. eulo from which it differs in its slightly more ovate shell (see Fig. 2A compared with 2B, C) and in the inner side of the operculum being simple. In addition, the female genital system differs in the posterior loop of the renal oviduct not extending to the posterior end of the bursa copulatrix and the bursal duct being markedly longer, joining the common duct some distance anterior to the seminal receptacle. The distal part of the penis has a double flange in Eu. eulo but only a single flange in Eu. fenshami. The molecular results also show these species as distinct, with Eu. fenshami clustering with species from the Yowah Creek Springs on a tributary of the Paroo River system (see below), which are about 35 km NW. The only spring in which Eu. fenshami is known to occur is on the main Paroo River, while the springs containing Eu. eulo and Eu cf. eulo are on tributaries to the west and separated from them by about 52 km and 42.5 km respectively. Snails were first noticed at this site by Dr R. Fensham. Regrettably, Dr Fensham has recently reported (pers. comm. to WFP in Oct. 2017) that in 2012, and confirmed in 2014, the spring appears to be extinct.
A discriminant function analysis using the shell measurements of E. eulo, E. cf. eulo and E. fenshami successfully classified 95% of E. eulo, 90% of E. cf. eulo and 100% of E. fenshami (Wilks’s Lambda 0.096, p<0.000) (Fig. 9).
description: Published as part of Zhang, - H., 2019, New taxa of Tateidae (Caenogastropoda, Truncatelloidea) from springs associated with the Great Artesian Basin and Einasleigh Uplands, Queensland, with the description of two related taxa from eastern coastal drainages, pp. 1-67 in Zootaxa 4583 (1) on pages 12-15, DOI: 10.11646/zootaxa.4583.1.1, http://zenodo.org/record/2637603