Exiligada brabyi, 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 : 700-701

EXILIGADA BRABYI SP. NOV.

( FIGS 5B , 7D–E )

Exiligada negriensis – Solem, 1984: 673, plate 57F; figure 175 (a–c) (in part).

Holotype: AUSTRALIA, NT, VRD, east of Duncan Hwy , 37.7 km north-west of Kirkimbie Station H /S, large, open, and very rugged limestone formation, in talus, under spinifex, 17°26 ′ 59 ′′ S, 129°03 ′ 20 ′′ E (coll. V. Kessner, R. Hokkanen 2.ix.2009), wet ( WA – 81/09, WAM S83168 ).

Paratypes: Same data as for holotype, 27 dry, two wet ( WAM S49159 ); Duncan Rd , old Ord River homestead, Forrest Creek (Ck), 70 km north of Nicholson homestead, under limestone rocks and concrete of old structures, 17°23 ′ 56 ′′ S, 128°52 ′ 01 ′′ E (coll. R. Crookshanks, 29.i.2005), four dry, two wet ( AM C.443279) .

Etymology: In honour of Michael Braby, for his most valuable help with fieldwork in the Victoria River District, noun in genitive case.

Description: Shell ( Figs 5B , 7D, E ). Moderately large, moderately elevated, moderately thick; micropustulations absent; background colour yellowish horn fading to whitish towards shell base, with one faint to conspicuous, continuous, brown-reddish peripheral band, and few regularly spaced, narrower spiral bands, more conspicuous on body whorl, absent on shell base; no maculations.

Genitalia. Epiphallus as long as penis. Vas deferens entering penial sheath within anterior third. Penis five times longer than wide, not coiled inside sheath, with thick wall, inner penial wall with thick, regularly shaped, sometimes interrupted main longitudinal pilaster restricted to posterior half, with several thin longitudinal folds anteriorly. Vagina half as long as penis, as long as free oviduct. Bursa copulatrix with no well-differentiated end ( Solem, 1984: fig. 175, ‘ E. negriensis ’).

Remarks: Shell colour pattern not readily distinguishable from that of E. qualis . Solem’s (1984: 676, fig. 175) description of genital anatomy of ‘ E. negriensis ’ is here attributed to E. brabyi . Penis length relative to width (pl/pw) average, epiphallus length relative to penis (el/pl) half of average. Inner penial wall sculpture very similar to that of E. qualis and Exiligada unistriata , from which it can be distinguished by the posteriorly situated, main longitudinal pilaster being interrupted and by a larger number of anterior folds. Vagina length relative to penis and free oviduct (vl/pl, vl/ol) shorter than average.

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 7. SEM micrographs of Exiligada shells. A-C, E. negriensis Iredale, 1939 (WAM S49152). 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. brabyi sp. nov. (paratype WAM S49159). 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.