Nanotrachia undetermined

Köhler, Frank & Criscione, Francesco, 2013, Small snails in a big place: a radiation in the semi-arid rangelands in northern Australia (Eupulmonata, Camaenidae, Nanotrachia gen. nov.), Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 169 (1), pp. 103-123 : 120

NANOTRACHIA CORONATA SP. NOV.

Holotype

Australia, WA, EK, Osmond Range , 17 km northeast of Palm Yard, narrow limestone and sandstone ridge, with steep open slopes, talus, and Spinifex , in litter under rocks, 17°12′13″S, 128°24′50″E (coll. V. Kessner, 29 August 2009); dissected specimen ( WAM S66301 ).

Paratypes

Same as holotype; one wet ( WAM S49181 ), 11 dry ( WAM S49086 ) .

Other material: Table 1.

Etymology

In reference to the crown-like appearance of the peripheral keel because of the axial ribs continuing onto it, derived from ‘coronatus’ (Latin = bearing a crown), adjective of feminine gender.

Description

Shell ( Figs 4C , 5C, D ): Large; periphery shouldered, strongly keeled; spire weakly elevated; umbilicus open, wide, not concealed by columellar reflection; protoconch and teleoconch with dense, pointed periostracal projections and fine axial growth lines; teleoconch with weak, blunt, widely spaced axial ribs, not interrupted on keel; apertural lip reflected, moderately expanded; yellowish brown.

Genitalia: Epiphallus very short, one-quarter of penial length; no muscle fibres connect epiphallus and penial apex. Vas deferens entering penial sheath almost halfway up. Penial wall thin, with two longi- tudinal pilasters, one wide, irregular, comprising half of penial wall, second pilaster thinner, irregularly shaped, winding, with regularly spaced, pointed corrugations; penial pore surrounded by subcircular ridge. Vagina slightly shorter than penis, half to twice as long as free oviduct (identical to N. carinata sp. nov.; Fig. 6C ).

Comparative remarks

Largest species of genus. Shell similar to N. carinata sp. nov., but axial ribs continuing on keel; N. levis sp. nov. differing by absence of keel; N. orientalis with stronger ribs, other congeners with weaker keel. Genitalia identical to N. carinata sp. nov.

Figures

Figure 4. Shells of Nanotrachia species studied herein. A, N. intermedia (Solem, 1984) (paratype AM C.146110); B, Nanotrachia carinata sp. nov. (paratype WAM S49100); C, N. coronata sp. nov. (paratype WAM S49086); D, N. costulata costulata sp. nov. (WAM S49088); E, N. levis sp. nov. (paratype WAM S49096); F, N. orientalis (Solem, 1984) (paratype AM C.146105); G, Mouldingia occidentalis (Solem, 1984) (paratype AM C.146107). Scale bar = 1 cm.

Figure 5. SEM micrographs of shells showing protoconch and teleoconch microsculpture. A–B, N. carinata sp. nov. (paratype WAM S49100); C–D, N. coronata sp. nov. (paratype WAM S49086); E–F, Nanotrachia costulata sp. nov. (WAM S49088); G–H, N. levis sp. nov. (paratype WAM S49096). Scale bars: A, C, E, G = 1 mm; B, D, F, H = 200 Mm.

Figure 6. Penial anatomy. A, Nanotrachia intermedia (Solem, 1984) (WAM S49195); B, N. intermedia (Solem, 1984) (WAM S49194); C, Nanotrachia carinata sp. nov. (holotype WAM S66300); D, N. levis sp. nov. (holotype WAM S6630). Insets showing schematic cross section of mid-penis. Scale bar = 2 mm.