Nundalia secreta, 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 : 56-58

Nundalia secreta n. sp.

Material examined. Holotype: New South Wales, South Head Creek , on track 500 m SW from road between Snowball Road and Nundle Forest Way, Nundle SF, 31° 26' 53" S, 151° 16' 34" E, on weeds and clumps of saturated moss, W.F. Ponder, 23 Feb 1988, C.479959 . Paratypes: Same data, C. 200900, 20+. Other material examined: New South Wales, E of Nundle, Nundle S.F, Ponderosa Forest Park , Hanging Rock State Forest , Four Mile Creek tributary, ca. 200 m E of forestry camp, 31° 28' 03" S, 151° 15' 27" E, small slow-flowing clear stream, in moss and liverworts on rocks, W.F. Ponder, 23 Feb 1988 , C.400874, 1; C.410644, 8.

Shell ( Fig. 28A, B ). Ovate-conic, spire outline slightly convex, normally coiled, opaque. Length 1.7–2.0 mm (mean 1.8 mm), width 1.1–1.4 mm (mean 1.3 mm). Protoconch of about 1.5 whorls, with irregular transverse folds and scattered rather irregular pits on first half whorl, no folds and weaker on last whorl. Teleoconch whorls moderately convex, evenly rounded, total number 3.6–3.9 (mean 3.8). Umbilicus represented by chink only. Aperture pyriform, inner lip narrow, medium, firmly attached to parietal wall or slightly separated along its whole length, outer lip medium. Periostracum moderately developed, white or pale brown or yellow-brown.

Operculum ( Fig. 28C, D ). Transparent, pale yellow, slightly concave; with 2–3 small, white pegs on inner side.

Head-foot and external body. Unpigmented.

Mantle cavity. Ctenidium reduced, filaments 12–15, broadly triangular, apex right edge. Osphradium narrowly oval, towards posterior end of ctenidium, length relative to gill 0.21–0.28. Hypobranchial gland not distinguishable (absent). Rectum with U-shaped bend, faecal pellets longitudinally orientated, anus at or very near mantle collar or behind it. Kidney half or more in roof of mantle cavity. Renal gland transverse. Pericardium half or more in roof of mantle cavity, with short separation from posterior end of ctenidium.

Radula ( Fig. 29 ). Central teeth with cusp formula 3–6+1+3–6, basal cusps 2+2; median cusp sharp, about quarter to twice as long as adjacent cusps. Lateral teeth with cusp formula 4–5+1+5–6, main cusp narrow, little longer than adjacent cusps. Inner marginal teeth with about 21–24 cusps. Outer marginal teeth with approximately 22 cusps.

Female reproductive system ( Fig. 30B, C ). Ovary simple sac. Renal oviduct with short, anteriorly orientated U-shaped arch. Seminal receptacle near anterior edge of bursa, elongate, duct intermediate. Bursa copulatrix behind albumen gland, elongately-oval or triangular, shorter than albumen gland, bursal duct enters bursa anteroventrally, bursal duct joins coiled oviduct well behind 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, long.

Male reproductive system ( Fig. 30A ). Prostate gland mostly in mantle roof, oval, medium in cross section. Posterior pallial vas deferens straight or slightly undulating, anteriorly slightly undulating. Penis towards middle of head, intermediate, distal end tapering or narrow, blunt, terminal papilla absent or small. Etymology. Secretus—Latin, isolated.

Distribution and habitat. This tiny species is known from only two localities in the Great Dividing Range near Nundle ( Fig. 1 ) in the upper tributaries of the east-flowing Manning River. It is probably more widely distributed in that area than present sampling suggests. It is also possible that other similar species exist in this general area.

Remarks. This species differs from other Eastern Australian Tateidae in the characters given above under the genus.

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 28. Shell and operculum of Nundalia secreta n. gen. and n. sp. A. Shell of holotype (C. 479959). B. Protoconch (C.200900). C, D. Operculum, outer (C), and inner (D) sides (C.200900).

FIGURE 29. Radula of Nundalia secreta n. gen. and n. sp. (C.200900). A. Half row of radula. B. Detail of central teeth. Scale bar 10 µm.

FIGURE 30. Male and female reproductive anatomy of Nundalia secreta n. gen. and n. sp. (C.200900). A. Penis, showing penial duct and vas deferens. B. Female system from left side. C. Bursa copulatrix and seminal receptacle. Abbreviations: agalbumen gland; bc—bursa copulatrix; cg—capsule gland; o—opening of oviduct; p—papilla; pd—penial duct; pw—posterior wall of mantle cavity; ro—renal oviduct; sr—seminal receptacle; v—vestibule; vc—ventral channel. Scale bar 200 µm.