Parglogenia sp. nov. 'Croker Island'

Koehler, Frank & Shea, Michael, 2022, A new cryptic species of land snail from the Northern Territory, Australia (Stylommatophora, Camaenidae, Parglogenia), Zoosystematics and Evolution 98 (2), pp. 427-433 : 427

Parglogenia sp. nov. 'Croker Island'

Material examined.

AUSTRALIA · 1 preserved specimen, 4 dried shells; Northern Territory, Croker Island, near airstrip; 11°10'0"S, 132°29'6"E; leg. 28 Mar 1980; AM C.121141 (Fig. 2B ). 1 dried shell; Croker Island ; 11°7'S, 132°33'E; leg. 28 Mar 1980; AM C.582514 .

Description.

Shell (Fig. 2B ). Moderately large (D = 27.6-34.2 mm, H = 21.5-24.8 mm; n = 5), globose-conical with low domed spire, comprising 5 to 5.5 rounded whorls, moderately to rapidly increasing in diameter, separated by moderately to strongly incised suture. Teleoconch with microsculpture of widely to moderately spaced rounded pustules, in juveniles with short periostracal setae that are only retained along suture lines in adult specimens. Protoconch with microsculpture of elongate pustules arranged in oblique spirals. Umbilicus narrowly open. Outer lip moderately developed, outwardly reflected, without sulcus behind outer lip. Shell colour light brown, out lip pale pinkish to white (Fig. 2B ).

Reproductive anatomy (Fig. 3G, H ). Bursa copulatrix about a quarter to half of length of oviduct, with broad head, base broad above uterus junction, narrowing before spermathecal head. Epiphallus broad, narrowing at apex, length equivalent to about one fifth to one tenth of length of penis; retractor muscle attached to apex of epiphallus; vas deferens attached at apex of epiphallus, next to penial retractor; with small bi-lobed caecum at about one quarter of its length. Penis slightly kinked to bent above terminal end, cylindrical, about as long to twice as long as vagina. Penial walls very thick and muscular. Inner penial wall sculpture comprising lattice work of filaments below epiphallus, giving rise to longitudinal rows of interconnected thread-like filaments to corrugated pilasters toward genital pore; with one or two narrow, wrinkled longitudinal pilasters forming at around mid penis. Penial sheath absent (Fig. 3G, H ).

Comparative remarks.

Shell effectively indistinguishable from P. pelodes and P. cobourgensis . The few available specimens are at the larger end of the size distribution in this genus, but this might be a sampling artifact. Differs from P. pelodes most conspicuously in having a completely different penial wall sculpture that resembles P. cobourgensis . From P. cobourgensis , the Croker Island specimen differs in having a shorter bursa copulatrix, a broad spermathecal head, and a slightly longer epiphallus (one fifth of penis vs. one sixth to one tenth of penis length), inner penial wall has several longitudinal pilasters instead of only two.

Just a single historical specimen was available for dissection and not suitable for DNA extraction. For the paucity of suitable material, we refrain from a formal description of the Croker Island species.

Distribution.

Presumably endemic to Croker Island.

Figures

Figure 2. Shells. A. Parglogenia cobourgensis holotype AM C. 594396; B. Parglogenia sp. ' Croker Island' AM; C. 121141. Scale bar: 10 mm.

Figure 3. Anatomy of Parglogenia species. A-D. Parglogenia cobourgensis holotype AM C. 594396; A. Mantle roof; B. Head wart; C. Reproductive anatomy; D. Penial anatomy; E, F. Parglogenia cobourgensis paratype AM C. 460961; E. Reproductive anatomy; F. Penial anatomy; G, H. Parglogenia sp. ' Croker Island' AM C. 121141; G. Reproductive anatomy; H. Penial anatomy. Abbreviations: ag, albumen gland; at, atrium; bc, bursa copulatrix; ca, caecum; ep, epiphallus; epv, efferent pulmonary vessel; hd, hermaphroditic duct; ipw, inner penial wall; me, mantle edge; mr, mantle roof; ne, nephridium; p, penis; re, rectum; so, spermoviduct; ue, ureter; va, vagina; vd, vas deferens; vt, ventricle. Scale bars: 10 mm (A, D, F, G); 2 mm (B).