Exiligada montejinni, 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 : 706-707

EXILIGADA MONTEJINNI SP. NOV.

( FIGS 6A , 17A–C , 18 )

Holotype: AUSTRALIA, NT, VRD, 15.5 km westsouth-west of Montejinni Stn H /S, 16°42 ′ 22 ′′ S, 131°37 ′ 28 ′′ E (coll. V. Kessner, M. Braby, T. Parkin, 29.vii.2010) ( AM C.475769).

Paratypes: AUSTRALIA, NT, VRD, same data as for holotype, 20 dry, two wet ( AM C.469982) .

Etymology: In reference to the type locality, Montejinni Station; noun in apposition.

Description: Shell ( Figs 6A , 17A–C ). Moderately large, moderately elevated, thin; protoconch and teleoconch whorls with fine radial growth lines, micropustulations present. Shell background colour entirely yellowish horn and fading to whitish towards the base, sometimes with a darker subsutural area, never resembling a band.

Genitalia ( Fig. 18 ). Epiphallus as long as penis. Vas deferens entering penial sheath from one third up. Penis four times longer than wide, not coiled inside sheath, with inner wall supporting few longitudinal pilasters, some of which merging anteriorly into a single structure, some others running independently along wall. Vagina slightly shorter than penis and free oviduct, bursa copulatrix with short, rounded, well-differentiated end.

Remarks: Teleoconch microsculpture differing from that of E. monochroma by presence of micropustulations. Together with E. unistriata widest umbilicus of genus. Spiral bands always absent; readily distinguished from E. monochroma by its lighter yellowish horn shell background colour. Penis length relative to width (pl/pw) smaller than average and E. monochroma ; epiphallus length relative to penis (el/pl) average. Inner penial wall sculpture similar to that of E. montejinni but with less organized pattern. Vagina length relative to penis (vl/pl) larger than average and smaller than E. monochroma ; vagina length relative to free oviduct (vl/ol) smaller than average and two times smaller than in E. monochroma .

Figures

Figure 6. Shells of Exiligada species. A, E. montejinni sp. nov. (paratype AM C.469982). B, E. nodulicauda sp. nov. (paratype WAM S49160). C, E. pallida sp. nov. (paratype WAM S49215). D, E. punctata sp. nov. (paratype WAM S49221). E, E. qualis Iredale, 1939 (holotype AM C.64866). F, E. rivifontis sp. nov. (WAM S49225). G, E. unistriata sp. nov. (paratype AM C.470460). Scale bar = 2 mm. Note that foot produces from some shells.

Figure 17. SEM micrographs of Exiligada shells. A-C, E. montejinni sp. nov. (paratype AM C.469982). 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. nodulicauda sp. nov. (paratype WAM S49160). A, Apical view showing protoconch and first whorl. B, Close-up from above of sculpture across entire shell. C, Microsculpture on teleoconch whorl. Scale bars: A-B, D-E = 1 mm, C, F = 0.5 mm.

Figure 18. Penial anatomy of E. montejinni sp. nov. (holotype C.475769). A. External anatomy of penial complex, penial sheath removed. B. Anatomy of inner penial wall and detail of epiphallus–penis junction. Scale bar = 5 mm; a = 1 mm.