Pravonitor kreffti ( Cox, 1864 )

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 : 1782-1784

Pravonitor kreffti ( Cox, 1864)

( Figures 4 , 14 (e–f), 18)

Helix kreffti Cox, 1864: 21 .

Helix (Thalassia) kreffti: Brazier 1876: 118 .

Nanina (Subg. Xesta Sect. Macrochlamys) kreffti: Tryon 1886: 219 , pl. 63, figs 98–99.

Nanina (Macrochlamys) kreffti: Cox 1909: 6 .

Nitor (Pravonitor) kreffti: Iredale 1937: 3 .

Pravonitor kreffti: Smith, 1992: 241 ; Stanisic et al. 2010: 300–301 (in part).

Material examined

Holotype. Status unknown, whereabouts unknown presumed lost, Cape York , Far North Qld, Australia.

Neotype. QM MO86003 . Green Hill , Thursday Island , Torres Strait , Far North Qld, Australia (−10.58, 142.28), 11 April 1985, J. Stanisic, D. Potter.

Paraneotype. QM MO15572 (same data as neotype) .

Other material. See Table 1 .

Diagnosis

External morphology. Shell ( Figure 14 (e–f)) medium-sized (SW 12.5–13.7 mm), golden brown, 5.0–5.7 whorls, subdiscoidal to subglobose with a rounded whorl profile; shell microsculpture with very fine to obsolete spiral grooves; umbilicus very narrow, sealed with a mucous plug, partially covered by reflected lip. Body grey with a cream sole (in alcohol). Right and median mantle lobes moderately small, left lobe small; shell lappets moderately large, narrow, tapering, right lappet longer than left. Caudal horn moderately large.

Genital anatomy. Genitalia ( Figure 18 ) with short vagina, internally with broad longitudinal pilasters; bursa copulatrix moderately long, duct broad at base, then narrowing, internally with broad longitudinal pilasters; bursa elongate. Penis large, narrow at base and becoming broader proximally, with a large blind tip; internally with no pilasters or with one pustulose longitudinal pilaster, internal wall sculptured with fine pustules; approx. 50–75% enclosed in penial tunica; penis sometimes folded longitudinally inside tunica. Epiphallus enters penis through a simple pore; epiphallus similar in length to penis; epiphallus 2 longer than epiphallus 1; moderately short epiphallic caecum present, with medial or apical attachment of the penial retractor muscle; flagellum long, slender, without obvious internal cryptae.

Remarks

The correct identity of this species requires some clarification. It was first described by Cox (1864) based on a single specimen collected by MacGillivray, with no figure and with only a brief description (including the dimensions diam. maj. 0.57, min. 0.49, alt 0.31 (uncertain), 6 whorls), and a rather general type locality of simply ‘Cape York’. Shortly afterwards, Cox (1868) synonymised the species with P. villaris , and figured the specimen under this name, with dimensions (width 0.5 inches; height 0.25 inches, shell 5 whorls) matching the figure given at natural size. Here, Cox (1868) gives the locality as ‘Cape York (Cox); Rocky Isles, near Cape Flattery (MacGillivray)’; however, this second locality is probably referring to G. villaris , which was described from Lizard Island.

Subsequent authors including Brazier (1876), Tryon (1886) and Cox (1909) treated kreffti and villaris as separate species. Brazier (1876) stated that he believed Cox’s type shell to come from Darnley Island in the Torres Strait, given the close similarity of the kreffti type to the Darnley Island species,and recorded villaris from Cape York and Albany Island (this latter reference was probably actually P. septentrionalis , since G. villaris is found considerably farther south).

Among material from Cape York, there are two species represented: one is relatively small (shells of 5.0–5.5 whorls are 7.8–9.3 mm in width) and is referred to above as P . kreffti ‘Cape York’. The other is much larger (shells of 5.3–5.8 whorls are 12.9–15.3 mm in width) and is conspecific with a group found primarily on the Inner and Near Western Torres Strait Islands, referred to above as P . kreffti ‘Inner/ Western Islands’ ; only a single lot from Cape York is known ( AM C.425474 from Simpson’s Bay, Utingu, coll. 1912) . Cox’s description, dimensions and figure match the larger species and we accept this as P . kreffti. The holotype was recorded as lost by Smith (1992), and cannot be found in the collections of AM or NHMUK . To clarify the taxonomic status of P . kreffti, we designate QM MO86003 from Waiben Island as a neotype in accordance with Art . 75 of the International Code of Zoological Nomenclature ( ICZN 1999) . This specimen was dissected and sequenced and used as a basis for our taxonomic description. It matches the dimensions of the holotype, and among the available ethanol-preserved specimens, is geographically closest to the original type locality . In accordance with Art . 76 of the Code , Green Hill , Thursday (= Waiben) Island becomes the type locality of this species .

The distribution of Pravonitor kreffti was previously recorded from Weipa, east to Portland Roads and north to Bamaga on Cape York, and also the Torres Strait Islands ( Stanisic et al. 2010). It is now limited to the very tip of Cape York, and the Near Western and Inner Islands of the Torres Strait ( Figure 4 ), including Waiben, Muralug, Mua and Badu Islands, and probably numerous additional islands including Ngurupai (= Horn), Maururra (= Wednesday), Gealug (= Friday) and Kiriri (= Hammond) Islands. Populations from islands in the Central and Top Western groups and the southern coast of New Guinea are provisionally referred to P. annulus , and populations from the Eastern Islands (including Mer Island) are placed in P. insularum . Pravonitor kreffti can be distinguished from P. annulus by its slightly larger size, higher spire and rounded rather than subangulate whorl profile, and by the lack of a supraperipheral band.

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 18. Genitalia of Pravonitor kreffti, QM MO86003 (neotype), Thursday Island. a) Reproductive system. b) Penis interior. Scale bars: 1 mm.