Parglogenia cobourgensis, Köhler & Shea, 2022

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 cobourgensis sp. nov.

Holotype.

AUSTRALIA · 1 preserved specimen; Northern Territory, Cobourg Peninsula, 3.4 km NE of Black Point Ranger Station; 11°08'27.6"S, 132°10'12.0"E; vine thicket; leg. Vince Kessner, 4 Feb 2007; AM C.594396 (Fig. 2A ).

Paratypes.

AUSTRALIA · 1 preserved specimen; same data as holotype; AM C460965. 2 preserved specimens; Northern Territory, Cobourg Peninsula, Black Point nr barge landing; 11°9'18"S, 132°8'44"E; leg. Vince Kessner, 2 Feb 2007; AM C.460961.

Type locality.

Australia, Northern Territory, Cobourg Peninsula, 3.4 km NE of Black Point Ranger Station (11°08'27.6"S, 132°10'12.0"E).

Etymology.

For Cobourg Peninsula, where this species occurs.

Additional, non-type material.

AUSTRALIA · 1 dry shell; Northern Territory, Port Essington; 11°16'S, 132°9'E; leg. 1900; AM C.64926.

Description.

Shell (Fig. 2A ). Moderately large (D = 24.4-29.9 mm, H = 19.2-23.1 mm; n = 7), 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, outer lip pale pinkish to white (Fig. 2A ; based on 2 specimens).

Reproductive anatomy (Fig. 3C-F ). Bursa copulatrix about a quarter to half of length of oviduct, with slightly enlarged to broad head, base broad above uterus junction becoming inflated and then narrowing before spermathecal head. Epiphallus broad and bulb-like or 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 straight to 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. 3C-F ; based on 2 specimens).

Head wart oval to trunk-shaped, about 2 × 3 to 3 × 5 mm in size (Fig. 3B ); mantle roof typically camaenid (Fig. 3A ).

Comparative remarks.

Shell effectively indistinguishable from Parglogenia pelodes . Fewer shells of P. cobourgensis were available for examination. These completely overlapped in size range with P. pelodes occupying a smaller size range overall. This species differs from P. pelodes most conspicuously in having a completely different penial wall sculpture ( P. pelodes has longitudinal corrugated ridges) and by having much shorter penis, epiphallus, vagina, and bursa copulatrix.

Distribution.

The distribution of Parglogenia cobourgensis is difficult to delineate due to the paucity of suitable material. Here, the known distribution of P. cobourgensis is restricted to the Cobourg Peninsula and coastal parts of west Arnhem Land excluding Croker Island (see below). Denser sampling is required to delimitate the distributions of P. pelodes and P. cobourgensis more accurately and to clarify the taxonomic status of the Croker Island population.

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).