Exiligada gregoriana, Criscione & Law & Köhler, 2012

Criscione, Francesco, Law, Margot Louisa & Köhler, Frank, 2012, Land snail diversity in the monsoon tropics of Northern Australia: revision of the genus Exiligada Iredale, 1939 (Mollusca: Pulmonata: Camaenidae), with description of 13 new species, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 166 (4), pp. 689-722 : 703

EXILIGADA GREGORIANA SP. NOV.

( FIGS 5E , 12A–C , 13 )

Holotype: AUSTRALIA, NT, VRD, Gregory NP, 41.5 km south-south-east of Bullita O /S, 16°28 ′ 47 ′′ S, 130°32 ′ 11 ′′ E (coll. V. Kessner, 14.vii.2008) ( AM C.475766).

Paratypes: AUSTRALIA, NT, VRD , same data as for holotype, 23 dry, one wet ( AM C.462768); 30 km south-south-west of Timber Creek , NT, 15°46 ′ 16 ′′ S, 130°13 ′ 41 ′′ E (coll. V. Kessner, S. Roberts, 12.vii.2008), four wet ( AM C.462820) .

Etymology: Name chosen for similarity with Adansonia gregorii , the baob tree under which snails were found, and the name of Gregory National Park, derived from ‘gregorianus’ (Latin), adjective of feminine gender.

Description: Shell ( Figs 5E , 12A–C ). Moderately large, moderately elevated, moderately thin; micropustulations absent; background colour brownish horn fading to whitish towards shell base, without band or with one conspicuous to faint, continuous, relatively wide, brown-reddish peripheral band; no maculations.

Genitalia ( Fig. 13 ). Epiphallus two times longer than penis. Vas deferens entering penial sheath within anterior third. Penis four times longer than wide, not coiled inside sheath, inner penial wall with highly complex sculpture formed by several crowded, irregularly shaped, corrugated longitudinal pilasters running along entire wall length, giving rise to padlike thickenings. Vagina one quarter shorter than penis and free oviduct, bursa copulatrix with short, rounded, well-differentiated end.

Remarks: Along with E. calciphila and E. rivifontis , largest number of shell whorls. Teleoconch microsculpture differing from that of E. calciphila by presence of micropustulations. Shell colour pattern very similar to E. floraevallis , E. calciphila , E. limbunya , E. rivifontis , and E. unistriata . Penis length relative to width (pl/pw) average and longer than in E. calciphila . Epiphallus length relative to penis (el/pl) two times the average and as long as in E. calciphila . Penial inner wall sculpture almost identical to E. calciphila , but having more pilasters with increased corrugation. Vagina length relative to penis (vl/pl) larger than average and E. calciphila . Vagina length relative to free oviduct (vl/ol) shorter than average and E. calciphila .

Figures

Figure 5. Shells of Exiligada species. A, E. negriensis (holotype AM C.64865). B, E. brabyi sp. nov. (paratype C.443279). C, E. calciphila sp. nov. (paratype C.462723). D, E. floraevallis sp. nov. (paratype WAM S49204). E, E. gregoriana sp. nov. (paratype AM C.462820). F, E. limbunya sp. nov. (paratype AM C.470205). G, E. longicauda sp. nov. (paratype WAM S49228). H, E. monochroma sp. nov. (paratype AM C.469772).

Figure 12. SEM micrographs of Exiligada shells. A-C, E. gregoriana sp. nov. (paratype AM C.462768). A, Apical view showing protoconch and first whorl. B, Close-up from above of sculpture across entire shell. C, Microsculpture on teleoconch whorl. D-F, E. limbunya sp. nov. (holotype C.475866). D, Apical view showing protoconch and first whorl. E, Close-up from above of sculpture across entire shell. F, Microsculpture on teleoconch whorl. Scale bars: A-B, D-E = 1 mm, C, F = 0.5 mm.

Figure 13. Penial anatomy of E. gregoriana sp. nov. (holotype AM C.475766). Scale bar = 5 mm.