Edgbastonia (Barcaldinia) corrugata umbilicata, Zhang, 2019

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, Zootaxa 4583 (1), pp. 1-67 : 28-31

Edgbastonia (Barcaldinia) corrugata umbilicata n. subsp.

Material examined. Holotype: Queensland, Myross Station , main spring, 22° 47' 06" S, 145° 26' 00" E, at spring edge, amongst grass and on mud, W.F. Ponder & A. Davis, 6 Oct 2002, C.479946 . Paratypes: Same data, C.415845, 20+; QM MO85774 , 5 . Other material examined: Queensland, Myross Station , main spring, 22° 47' 07" S, 145° 26' 05" E, W.F. Ponder, R. Fairfax & R. Fensham, 13 Sep 2006, C.458219, 20+; 22° 47' 42" S, 145° 26' 26" E, 1 Jul 2008, R.J. Fensham & R. Fairfax, C.462094, 10+; 22° 47' 27" S, 145° 26' 27" E, 1 Jul 2008, R.J. Fensham & R. Fairfax, C.462092, 20+. Other material from the same locality : C.483045 12; C.483114, 20+; C.483112, 20+; C.483107, 20+; C.483110, 5; C.483113, 20+; C.483111, 5; C.483044, 20+; C.483108, 20+; C.483109, 3, C.505944,20+; C.505941,1; C.505949, 20+; C.505945, 20+, C.505951, 20+, C.505943, 1; C.505950, 12; C.505948, 5; C.505942, 13; C.505946, 5.

Shell ( Fig. 13G ). Ovate, spire outline moderately convex, normally coiled, translucent. Length 2.2–2.6 mm (mean 2.4 mm), width 1.8–2.5 mm (mean 2.1 mm). Protoconch about 1.2–1.3 whorls, distinctly pitted. Teleoconch whorls weakly convex, evenly rounded, total number 3.2–4.3 (mean 3.8). Umbilicus moderately wide. Aperture ovate, inner lip narrow, thin or medium, in partial contact to slightly separated from parietal wall, outer lip thin or medium. Periostracum moderately developed, pale yellow or yellow-brown.

Operculum ( Fig. 14I, J ). Transparent, colourless, slightly concave. Inner side lacking white smear, simple.

Head-foot and external body. Snout, tentacles unpigmented or pigmented, neck, dorsal and lateral foot and opercular lobes unpigmented, mantle roof unpigmented or weakly pigmented, visceral coil weakly pigmented.

Mantle cavity. Ctenidium well-developed, filaments 24–28, broadly triangular, apex right edge. Osphradium narrowly oval, towards posterior end of ctenidium, length relative to gill 0.22–0.31. Hypobranchial gland moderately developed. Rectum with U-shaped bend, faecal pellets longitudinally orientated or orientated obliquely or sideways, anus at mantle collar or a little behind it. Kidney half or more in roof of mantle cavity. Renal gland transverse. Pericardium half or more in roof of mantle cavity, overlapping posterior end of ctenidium.

Radula ( Fig. 19C, D ). Central teeth with cusp formula 3–4+3–5, basal cusps 1+1+1; median cusp sharp, about twice as long as adjacent cusps. Lateral teeth with cusp formula 3–4+1+3–4; main cusp sharp, about twice as long as adjacent cusp on outer side, slightly longer than adjacent cusp on inner side. Inner marginal teeth with 15–19 cusps. Outer marginal teeth with 12–15 cusps.

Female reproductive system ( Fig. 16J, K ). Ovary weakly to strongly lobed. Renal oviduct with rather small, U-shaped arch. Seminal receptacle anterior to bursa, oval, duct intermediate; sometimes orientated sperm in renal oviduct and/or bursal duct. Bursa copulatrix overlapping albumen gland on left, round or triangular, shorter than albumen gland, bursal duct enters bursa antero-ventrally, bursal duct joins coiled oviduct little behind posterior mantle cavity wall. Albumen gland partly in mantle cavity. Capsule gland with two distinct glandular zones, thick in cross section, markedly indented by rectum. Anterior vestibule large, opening anterior to capsule gland, short, cowl and/or gutter associated with oviduct opening present.

Male reproductive system ( Figs. 17F , 18G ). Prostate gland less than half in mantle roof, bean-shaped, thick in cross section. Posterior pallial vas deferens coiled, anteriorly slightly undulating. Penis towards middle of head, intermediate, distal end tapering, terminal papilla absent, large non-glandular distal lobe present.

Etymology. Umbilicus—Latin, navel. A term used in gastropods for a depression or perforation in the base of the shell.

Distribution and habitat. Known only from a large, shallow spring-fed pool on Myross Station ( Fig. 1 ). Abundant, living in fine silt on the bottom of the pool. It was not found in vegetated areas around the edge of the pool.

Remarks. This subspecies is very similar to Ed. (B.) corrugata corrugata but differs in having less welldeveloped axial sculpture, and the inner lip is in contact with the parietal wall or only slightly separated from it, instead of being widely separated. The female genital system is very similar to that of Ed. (B.) corrugata corrugata but differs in having a smaller, shorter bursa copulatrix with a narrower duct. The central teeth of the radula in the new subspecies are unusual in having only a single pair of basal cusps developed (cf., Ponder & Clark 1990, fig.8D, E), although a rudimentary second cusp is rarely seen.

A discriminant function analysis using five shell measurements of the four large globular species, Ed. corrugata corrugata , Ed. corrugata umbilicata , Ed. edgbastonensis and Ed. coreena , gave the following results (Wilks’s Lambda 0.236 p<0.000); overall 78% were correctly classified with Ed. coreena being the least correctly placed (42%) with specimens distributed between Ed. corrugata corrugata and Ed. edgbastonensis while Ed. corrugata corrugata was 77% correctly classified with some specimens being incorrectly classified as Ed. edgbastonensis and Ed. corrugata umbilicata . Ed. edgbastonensis was only 64% correctly classified with most of those going to Ed. corrugata corrugata . Ed. corrugata umbilicata was the most successfully classified (98%) with only one specimen being misclassified as Ed. corrugata corrugata ( Fig. 20A ).

The new subspecies is unusual in that the egg capsules are laid on the shell, a habit not observed in other taxa, including the typical subspecies, and this is presumably due to the lack of hard substrate and vegetation in the habitat it occupies.

Various water birds such as spoonbills ( Platalea sp., Threskiornithidae ) and several species of ducks were common in the pool and were feeding in the mud, suggesting that this rather abundant snail is probably utilised as a food item.

Figures

FIGURE 1. Map of the spring supergroups associated with the Great Artesian Basin (GAB) in Queensland, showing the main non-town locations mentioned in the text (squares) and some of the towns in the area (ovals). The pale grey shading is the discharge part of the GAB, the dark grey the recharge part. The inset map of Australia shows the area illustrated. The approximate location of Conondale is indicated by a triangle and Nundle by a star. The spring supergroups are outlined with dotted lines and are as follows: A, Mulligan River; B, Springvale; C, Flinders River; D, Hughenden; E, Barcaldine (see inset at upper right for details); F, Springsure; G, Eulo.

FIGURE 13. Shells of species of Edgbastonia (Barcaldonia) n. subgen. A. Edgbastonia (B.) hufferensis n. sp., holotype (C.479951). B. Edgbastonia (B.) cf. pallida (Ponder & Clark, 1990) (C. 479947). C, D. Edgbastonia (B.) routhensis n. sp., Routh Stn, C, holotype (C.479960). D. paratype (C.448850). E, Edgbastonia (B.) pagoda n. sp., holotype, Myross Stn (C.479948). F. Edgbastonia (B.) rugosa n. sp., holotype, Myross Stn (C.479949). G. Edgbastonia (B.) corrugata umbilicata n. sp., holotype, Myross Stn (C.479946). H. Edgbastonia? conjuboyensis, holotype, Conjuboy Stn (C.479956). I. Edgbastonia (B.) chillagoensis, holotype, Chillagoe Stn (C.479958). Scale bar 1 mm.

FIGURE 14. Opercula of species of Edgbastonia (Barcaldonia) n. subgen. A. Edgbastonia (B.) hufferensis n. sp., internal view (C.423238). B, C. Edgbastonia (B.) cf. pallida (Ponder & Clark, 1990). B. External view. C. Internal view (C. 457755). D, E. Edgbastonia (B.) routhensis n. sp. D. External view. E. Internal view (C438551). F, G. Edgbastonia (B.) pagoda n. sp. F. External view. G. Internal view (C.457756). H. Edgbastonia (B.) rugosa n. sp., internal view (C.457753). I, J. Edgbastonia (B.) corrugata umbilicata n. subsp. I. External view. J. Internal view (C.415845). K, L. Edgbastonia? conjuboyensis n. sp. K. External view. L. Internal view (C.445416). M, N. Edgbastonia (B.) chillagoensis n. sp. M. External view. N. Internal view (C.438557). Scale bar 200 µm.

FIGURE 16. Female reproductive system of species of Edgbastonia (Barcaldonia) n. subgen., shown from left side. A, B. Edgbastonia (B.) hufferensis n. sp. (C.423238). C, F. Edgbastonia (B.) cf. pallida (Ponder & Clark, 1990) (C.457755). D, E. Edgbastonia (B.) routhensis n. sp. (C.438551). G, H, Edgbastonia (B.) pagoda n. sp. (C.457756). I, L. Edgbastonia (B.) rugosa n. sp. (C.457753). J, K. Edgbastonia (B.) corrugata umbilicata n. subsp., (C.415845). M, N. Edgbastonia? conjuboyensis n. sp. (C.445416). O, P. Edgbastonia (B.) chillagoensis n. sp. (C.438557). Abbreviations: ag—albumen gland; bc—bursa copulatrix; cg—capsule gland; o—opening of oviduct; pw—posterior wall of mantle cavity; ro—renal oviduct; sr—seminal receptacle; vc—ventral channel. Scale bars 200 µm.

FIGURE 17. Prostate and vas deferens of species of Edgbastonia (Barcaldonia) n. subgen. A. Edgbastonia (B.) hufferensis n. sp. (C.423238). B. Edgbastonia (B.) cf. pallida (Ponder & Clark, 1990) (C.457755). C. Edgbastonia (B.) routhensis n. sp. (C.438551). D. Edgbastonia (B.) pagoda n. sp. (C.457756). E. Edgbastonia (B.) rugosa n. sp. (C.457753). F. Edgbastonia (B.) corrugata umbilicata n. subsp. (C.415845). G. Edgbastonia? conjuboyensis n. sp. (C. 445416). H. Edgbastonia (B.) chillagoensis n. sp. (C.438557). Abbreviations: avd—anterior vas deferens; pg—prostate gland; pvd—posterior vas deferens; pw—position of posterior wall of pallial cavity. Scale bars 200 µm.

FIGURE 18. Penis and vas deferens of species of Edgbastonia (Barcaldonia) n. subgen. A. Edgbastonia (B.) hufferensis n. sp. (C.423238). B, C. Edgbastonia (B.) cf. pallida (Ponder & Clark, 1990) (C.457755). D, Edgbastonia (B.) routhensis n. sp. (C.438551). E. Edgbastonia (B.) pagoda n. sp. (C.457756). F. Edgbastonia (B.) rugosa n. sp. (C.457753). G. Edgbastonia (B.) corrugata umbilicata n. subsp. H, I. Edgbastonia? conjuboyensis n. sp. (C.445416). J, K. Edgbastonia (B.) chilagoensis n. sp. (C.438557). Abbreviations: avd—anterior vas deferens; ngl—non-glandular lobe; p—papilla; pd—penial duct. Scale bars 200 µm.

FIGURE 19. Radulae of species of Edgbastonia (Barcaldonia) n. subgen. A, B. Edgbastonia (B.) rugosa n. sp. A. Half row. B. Lateral teeth (C.457753). C, D. Edgbastonia (B.) corrugata umbilicata n. subsp. C. Half row. D. Lateral and marginal teeth (C.415845). E, F. Edgbastonia? conjuboyensis n. sp. E. Half row. F. Marginal teeth (C.445416). G, H, I. Edgbastonia (B.) chillagoensis n. sp. G. Half row. H. Lateral and marginal teeth. I. Outer marginal teeth (C.438557). Scale bars 10 µm.

FIGURE 20. Canonical scores plot of five shell measurements of species of Edgbastonia (Barcaldonia) n. subgen. A. Members of the Ed. (B.) edgbastonensis-corrugata species-group: Ed. (B.) corrugata corrugata (x), Ed. (B.) coreena (Ǫ), Ed. (B.) edgbastonensis (+), and Ed. (B.) corrugata umbilicata (D). B. Members of the Ed. (B.) colmani-pallida species-group: Ed. (B.) colmani (x), Ed. (B.) pallida (Ǫ) and Ed. (B.) cf. pallida (+). C. Members of the Ed. (B.) jesswiseae- zeidlerorum speciesgroup: Ed. (B.) jesswiseae (x), Ed. (B.) acuminata (Ǫ), Ed. (B.) carinata (+), Ed. (B.) zeidlerorum (s) and Ed. (B.) rugosa (D). Ellipse p: 0.6827.