Pravonitor monteithi ( Stanisic, 2010 )

Hyman, Isabel T. & Köhler, Frank, 2022, Homoplasy in shells discombobulated the taxonomy: revision of the larger helicarionid land snails of northern Queensland, Australia (Stylommatophora: Helicarionidae), Journal of Natural History 56 (41 - 44), pp. 1727-1799 : 1784-1786

Pravonitor monteithi ( Stanisic, 2010)

( Figures 4 , 14 (g), 19)

Malandena monteithi Stanisic, 2010: 296–297 .

Holotype. QMMO48587, Isley Hills , north-eastern Qld, Australia (17°03ʹS, 145°42ʹE), rainforest, 1050 m, under logs, 30 November 1993, G. Monteith, H. Janetzki, D. Cook.

Paratypes. QMMO24798, QMMO48164, QMMO48203, QMMO48693, QMMO78927, AM C .425580.

Other material. See Table 1 .

Diagnosis

External morphology. Shell ( Figure 14 (g)) medium-sized (SW 11.9–13.5 mm), amber with a darker underside, 5.1–5.4 whorls, subdiscoidal with a low spire, whorl profile rounded; microsculpture of very fine to obsolete spirals on protoconch and teleoconch; umbilicus very narrow, partially covered by reflected lip. Body white with black eyestalks (in alcohol). Mantle lobes moderately small; shell lappets moderately large, narrow, tapering. Caudal horn large.

Genital anatomy. Genitalia ( Figure 19 ) with short vagina, internally with longitudinal pilasters; bursa copulatrix moderately short, duct broad at base, then narrowing, internally with distinct longitudinal pilasters; bursa elongate. Penis moderately small, bulging at base, tubular medially, swollen proximally with large blind tip; internally with 1–2 pustulose longitudinal pilasters, internal wall sculptured with fine pustules; basal bulge with thickened, folded region internally; basal bulge not enclosed in penial tunica. Epiphallus enters penis through a simple pore; epiphallus longer than penis; epiphallus 2 longer than epiphallus 1; moderately long epiphallic caecum present, with medial attachment of the penial retractor muscle; flagellum long, slender, without obvious internal cryptae. Spermatophore with soft capsule and smooth, elongate tail-pipe with no sculpture.

Remarks

Pravonitor monteithi was previously included in Malandena (now Elatonitor ) and bears a strong external similarity to Elatonitor suturalis and P. aquilonia . It can be distinguished by its smaller size, finer teleoconch sculpture and rounded whorl periphery. The presence of an epiphallic caecum with a medial attachment of the penial retractor muscle and an internally pustulose penis interior definitively places this species in Pravonitor . Only a single specimen could be sequenced,and this sequence diverged from within the clade P. aquilonia . It is possible that P. monteithi should be recognised as a synonym of P. aquilonia ; however, there are distinct morphological differences between the two and we believe there is insufficient information to synonymise the two species. Specimens identified in the current study as Pravonitor monteithi had a penis with a large, swollen blind tip, and a basal bulge containing a thickened, folded region, as well as 1–2 penial pilasters. In contrast, P. aquilonia is significantly larger, and has a penis that is narrowed proximally with no blind tip, no penial pilasters, and no thickened, folded region basally.Hence,the two species are retained as separate based on morphological differences despite the close relationship shown in the mitochondrial tree. It is possible that these species have diverged very recently and that the morphological differences are not yet reflected in the tree.

This species is recorded from rainforest in the Atherton Tablelands and adjacent coastal ranges ( Stanisic et al. 2010); however, in the current study only specimens from Lamb Range and from the adjacent northern parts of the Atherton Tableland (e.g. Tinaroo, Lake Eacham) could be confirmed as belonging to P. monteithi ( Figure 4 ). Other specimens from the Atherton Tableland preliminarily identified as P. monteithi were found to be either M. suturalis or P. aquilonia . Further collecting throughout this area to confirm the distribution of these three very similar species would be of great benefit.

Figures

Figure 4. Distribution map. Grey symbols: Geminitor. Blue symbols: Pravonitor. Red symbols: Elatonitor. Biogeographic barriers are marked in black; A = Normanby Basin, B = Black Mountain Corridor, and C = Atherton Tableland.

Figure 14. Shells of Pravonitor. a) Pravonitor insularum, AM C.170795 (paratype). b) Pravonitor annulus AM C.425415,Gabba Is. c) Pravonitor aquilonia, QM MO48285 (holotype). d) Pravonitor ferrugineus, QM MO12752 (holotype). e). Pravonitor kreffti, AM C.1352, Thursday Is. f) Pravonitor kreffti, AM C.425474, Simpson’s Bay, Utingu. g) Pravonitor monteithi, QM MO48587 (holotype). h) Pravonitor septentrionalis, AM C.425422. i) Pravonitor stuarti, QM MO80213 (paratype). Scale bar: 5 mm.

Figure 19. Genitalia of Pravonitor monteithi. a) QM MO48669, Isley Hills. Reproductive system. b-c) QM MO48203, Lamb’s Head. b) Spermatophore. c) Penis interior. Scale bars: 1 mm.