Nitor circumcincta ( Cox, 1868 )

Hyman, Isabel T. & Ponder, Winston F., 2010, A morphological phylogenetic analysis and generic revision of Australian Helicarionidae (Gastropoda: Pulmonata: Stylommatophora), and an assessment of the relationships of the family 2462, Zootaxa 2462 (1), pp. 1-148 : 59-61

Nitor circumcincta ( Cox, 1868)

Figures 10D , 11D , 16B, F , 17J–L , 18E , 19E , 20D , 21E , 22A

Helix marmorata Cox, 1864: 20 [not Helix marmorata of Férussac, 1821].

Helix (Xesta) circumcincta Cox, 1868: 3 , pl. 5, figs 6a–b [nom. nov. for Helix marmorata Cox, 1864 ].

Nanina (subg. Xesta, sect. Macrochlamys ) marmorata: Tryon, 1885: 105 , pl. 35, figs 39–40.

Nanina marmorata: Hedley, 1888: 50 .

Microcystis circumcincta: Gabriel, 1930: 85–86 .

Melocystis circumcincta: Iredale, 1937c: 5 ; Smith, 1992: 238.

Material examined. New South Wales, Australia: Possible syntype: AM C104161 (one shell measured, photographed), Kiama (34º40' S, 150º51' E), pre 1864, G. Masters .

Other material: AM C365822 (one specimen dissected; juvenile), bottom of Macquarie Pass , ca. 300 m along walking track (34º34.37' S, 150º40.6' E), in leaf litter from subtropical rainforest, 6 Jul. 1999, L. Brincat ; AM C356607 (two specimens dissected; one radula examined), NW of Kiama, near Jamberoo , Jamberoo Mt., (34º39' S, 150º42' E), in leaf litter in rainforest, 8 Nov. 1987, G. Hunt & party .

Description. External morphology: Shell ( Figures 16B, F , 19E , 20D , 21E ) 4.3 whorls, golden brown with a broad peripheral colourless band; shell shape and sculpture as for genus; whorl profile flattened above and below sub-angular periphery; umbilicus open, very narrow U-shape. Animal cream and grey. Mantle laps moderately small, as for genus; mantle lobes as for genus. Caudal horn moderately small; caudal foss diamond-shaped slit in tail.

Mantle cavity ( Figure 10D ): As for genus. Mantle with faintly visible minor blood vessels, pigmentation of black and white spots, mantle gland absent.

Digestive system: As for genus.

Genital system ( Figures 18E , 22A ): As for genus. Bursa copulatrix internally with longitudinal pilasters. Penis long; epiphallus enters penis through two fleshy lips; penis internally smooth, four to five longitudinal penis pilasters present, penial diverticulum absent. Penial sheath present, enclosing only base of penis. Epiphallus longer than penis, internally with longitudinal pilasters. Spermatophore as for genus.

Radula (17J–L): As for genus. Radular formula (~58.10.1.10.~58) × at least 80 rows.

Range and habitat. Nitor circumcincta is found from Moruya in southeastern New South Wales to the Royal National Park, south of Sydney, usually in rainforest and vine thickets but sometimes in wet sclerophyll forest. There is also a single specimen known from south of Eden, close to the New South Wales-Victoria bor- der. Specimens are usually found under rocks or in leaf litter.

Remarks. Nitor circumcincta is synonymised here with Helix marmorata ( Cox 1864) . However, the species referred to as Microcystis marmorata by Odhner (1917) was probably Nitor subrugata ( Iredale 1941) .

Nitor circumcincta has previously been included in the genus Melocystis . However, Iredale (1941) grouped Melocystis (then containing only circumcincta ) with Nitor in the family Nitoridae . In the current study, N. circumcincta did not group with the other Nitor species in the phylogenetic analysis ( Figure 4 ). Despite this, the strong anatomical similarities between N. circumcincta , N. wiangariensis and N. subrugata (flagellum type, epiphallic caecum and attachment of penis retractor muscle, vagina length, internal structure of the penis, spermatophore sculpture) suggest that this is the best current placement of this species. Nitor circumcincta lacks the peripheral keel present on the shells of N. wiangariensis and N. subrugata ; however, it shares the flattened whorl profile seen in both species and has a slightly angulate periphery.

Figures

FIGURE 4. Australian Helicarionidae. Majority-rule consensus tree of 13,839 trees, length 99. Where two or more species from a genus are included, the genera are shaded. Groups A and B are referred to in text.

FIGURE 10. Mantle cavities. A. Helicarion cuvieri, AM C424333. B. Brevisentis jacksoniensis, AM C356645. C. Stanisicarion freycineti, AM C391188. D. Nitor circumcincta, AM C365822. E. Tarocystis responsivus, AM C425327. F. New Caledonian species NC3, MNHN no registration number. Scale bars 1 mm (D–E), 2 mm (A–C, F). Abbreviations: dg, digestive gland; i, intestine; k, kidney; mc, mantle collar; mlo, median mantle lobe; pc, pericardium; pn, pneumostome; pv, pulmonary vein; rla, right mantle lap; rlo, right mantle lobe; ur1, primary ureter; ur2, secondary ureter.

FIGURE 11. Nervous systems. Cerebral commissure cut (cut regions shaded with diagonal lines). A. Helicarion cuvieri, AM C424333. B. Brevisentis atratus, AM C205294. C. Stanisicarion freycineti, AM C391188. D. Nitor circumcincta, AM C365822. E. Tarocystis responsivus, AM C425327. F. New Caledonian species NC3, MNHN no registration number. G. Ctenophila caldwelli, AM C205301. H. Madagascan species MA1, AM C205304. I. Macrochlamys petrosa, AM C205305. J. Everettia sp., BMNH 20020188. K. Coneuplecta pampini, AM C438751. L. Lamprocystis guttula, FMNH 174940. M. Trochomorpha rubens, FMNH 175247. Scale bars 1 mm except for J (scale bar 2 mm). Abbreviations: ce, cerebral ganglion; pa, parietal ganglion; pe, pedal ganglion; pl, pleural ganglion; vg, visceral ganglion.

FIGURE 16. Microsculptures of the protoconch (A–E) and teleoconch (F–I). SEM. A. Mysticarion porrectus, AM C165048 (protoconch). B. Nitor circumcincta, AM C365822 (protoconch). C. Tarocystis responsivus, AM C425327 (protoconch). D. Coneuplecta calculosa, AM C377743 (protoconch). E. New genus C patescens, AM C120654 (protoconch). F. Nitor circumcincta, AM C365822 (teleoconch). G. Tarocystis responsivus, AM C425327 (teleoconch). H. Coneuplecta calculosa, AM C377743 (teleoconch). I. New genus C patescens, AM C120654 (teleoconch). Scale bars 100 mm (D, I), 200 mm (A–C, E–H).

FIGURE 17. Radulae. SEM. A–C. Fastosarion superba, AM C425248. D–F. Stanisicarion freycineti, AM C391188. G– I. Parmacochlea fischeri, AM C441743. J–L. Nitor circumcincta, AM C356607. M–O. Pravonitor kreffti, AM C425415. P–R. Expocystis rustica, AM C425540. Scale bars 20 mm (D–R), 50 mm (A–C).

FIGURE 18. Reproductive systems. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, QMMO19238. C. Eungarion mcdonaldi, AM C438760. D. Parmacochlea fischeri, AM C441743. E. Nitor circumcincta, AM C356607. F. Nitor subrugata, AM C334537. G. Pravonitor kreffti, AM C425415. H. Expocystis rustica, AM C425540. Scale bars 1 mm (E), 2 mm (A–D, G–H), 5 mm (F). Abbreviations: alb, albumen gland; bc, bursa copulatrix; c, caecum; ep, epiphallus; fl, flagellum; fov, free oviduct; her, hermaphrodite duct; m, muscle attaching penial sheath to epiphallus (only shown in A); ov, ovotestis; p, penis; pr, prostate; prm, penis retractor muscle; pt, penial sheath; ut, uterus; v, vagina; vd, vas deferens.

FIGURE 19. Shells, dorsal view. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, BMNH 197776 (S). C. Eungarion mcdonaldi, QMMO35628. D. Parmacochlea fischeri, AM C432179. E. Nitor circumcincta, AM C104161 (POS of Helix marmorata). F. Nitor subrugata, AM C333711. G.Nitor subrugata, AM C63479 (S of N. subrugata helmsianus). H. Pravonitor kreffti, BMNH no number (POS). I. Pravonitor kreffti, AM C29647 (H of P. kreffti insularum). J. Expocystis rustica, BMNH 1982243 (POH of Helix villaris). K. Malandena suturalis, AM C425087. Scale bars 3 mm (E, J), 5 mm (A–D, F–I, K). Photographs by H. Barlow (A, D, F, I), D. Beechey (E, G), I. Hyman (K), W. Ponder (B, H, J), copyright Australian Museum; photographer unknown, copyright Queensland Museum (C). Abbreviations: H, holotype; POH, possible holotype; POS, possible syntype; S, syntype.

FIGURE 20. Shells, lateral view. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, BMNH 197776 (S). C. Parmacochlea fischeri, AM C432179. D. Nitor circumcincta, AM C104161 (H). E. Nitor subrugata, AM C333711. F. Nitor subrugata, AM C63479 (S of N. subrugata helmsianus). G. Pravonitor kreffti, BMNH no number (POS). H. Pravonitor kreffti, AM C29647 (H of P. kreffti insularum). I. Expocystis rustica, BMNH 1982243 (POH of Helix villaris). J. Malandena suturalis, AM C425087. Scale bars 3 mm (A, D, I), 5 mm (B–C, E–H, J). Photographs by H. Barlow (A, C, E, H), D. Beechey (D, F), W. Ponder (B, G, I), I. Hyman (J). Abbreviations: H, holotype; POH, possible holotype; POS, possible syntype; S, syntype.

FIGURE 21. Shells, ventral view. A. Stanisicarion freycineti, AM C391188. B. Stanisicarion virens, BMNH 197776 (S). C. Eungarion mcdonaldi, QMMO35628 (H). D. Parmacochlea fischeri, AM C432179. E. Nitor circumcincta, AM C104161 (H). F. Nitor subrugata, AM C333711. G. Nitor subrugata, AM C63479 (S of N. subrugata helmsianus). H. Pravonitor kreffti, BMNH no number (POS). I. Pravonitor kreffti, AM C29647 (H of P. kreffti insularum). J. Expocystis rustica, BMNH1982243 (POH of Helix villaris). K. Malandena suturalis, AM C425087. Scale bars 3 mm (A, E, J), 5 mm (B–D, F–I, K). Photographs by H. Barlow (A, D, F, I), D. Beechey (E, G), I. Hyman (K), W. Ponder (B, H, J), copyright Australian Museum; photographer unknown, copyright Queensland Museum (C). Abbreviations: H, holotype; POH, possible holotype; POS, possible syntype; S, syntype.

FIGURE 22. Penis interiors. A. Nitor circumcincta, AM C356607. B. Nitor subrugata, AM C334537. C. Pravonitor kreffti, AM C425415. D. Expocystis rustica, AM C425540. E. Malandena suturalis, AM C425085. F. Echonitor cyrtochila, SAM D16557. G. Echonitor albumenoidea, SAM D16567. H. Periclocystis ardeni, SAM D16562. I. New Caledonian NC3, MNHN no registration number. J. New Caledonian NC5, MNHN no registration number. K. Caldwellia angularis, AM C205299. L. Caldwellia imperfecta, AM C205300. Scale bars 1 mm (A–L). Abbreviations: ep, epiphallus; pd, penial diverticulum; pp, penial pilaster; ppd, diamond-shaped, ridged pustules; prm, penis retractor muscle; ppu, penial pustules; pv, penial verge.