Kora arnaldoi, Pena, 2024

Pena, Meire Silva, 2024, Notes on Kora and description of a new species from Minas Gerais, Southeast Brazil (Mollusca: Gastropoda: Stylommatophora), Zoologia (e 23059) 41, pp. 1-11 : 6-8

Kora arnaldoi sp. nov.

Figs 5–6

https://zoobank.org/ 7B6783CA-E50C-4EB5-9C8D-31912E0805DE

Holotype: MNRJ 23623 , 1 specimen, H = 43mm, W = 18mm.

Type locality: BRAZIL, Minas Gerais, Itacarambi, Cavernas do Peruaçu National Park, Vale dos Sonhos, between crevices of the calcareous stones.

Diagnosis: shell oval-elongate with mammillary apex; light brown; total height more than three times width. Pro - toconch core lightly recessed, smooth until ½ whorl when it becomes fine and broken; riblets axial; spire shorter than body whorl and body whorl not inflated. Peristome color brownish-rose. Radula teeth with narrow base and curved free end forming single blunt cusp with a short canalicular depression, central tooth not distinct from other teeth. Mandible with 16 narrow central plates flanked by approximately 7x wider plate at each end.

Description: shell ( Fig. 5A–B ) elongated-oval, solid, rigid; mammillary apex forming angle of 47° or less; umbilicate; light (Küppers N 40 A 50 M 40) to medium brown (Küppers N 60 A 30 M 40); striated axially; 6 ½ slightly convex whorls; total height more than three times width. Protoconch ( Fig. 5C ) with two whorls; smooth near core until ~½ whorl; with ensuite fine and broken axial riblets; spire shorter than height of elongated body whorl. Aperture vertical, ovate, broadly expanded; peristome color brownish-rose (Küppers N 50 A 40 M 30) with larger posterior projection on body whorl; outer lip rounded, elongated, upper region oblique; basal lip rounded, vertical columellar margin with strong callus, with pleat that varies in size, shape, and position. Columellar axis without lamellae. Dimensions (mm/39 shells): H = 26.30–44.00; W = 9.10–14.80; ah = 9.70–15.50; aw = 4.10–6.90; wn = 7 ¼.

Soft parts: cephalopedal mass dark gray (Küppers N 80 M 20 C 10) with light-brown lateral foot edge. Foot holopodal, light brown, without papillae or ridges. Genital pore split located below right ommatophore. Mantle edge ( Fig. 6B ) with wide outer lobe and narrow inner lobe with horizontal flap covering the pneumostome and narrower flap at opposite end. Pallial chamber roof ( Fig. 6A ) pigmented with well-dilated vessels near the pneumostome on both sides of pulmonary vein; splits into three or four branches. Kidney approximately triangular and more extensive than pericardium. Pericardium partially opaque, shorter than kidney lateral face and more bulging next to pulmonary vein. Digestive system: jaw ( Fig. 5D ) with transverse pleating forming 16 narrow central plates flanked by approximately 7x wider plate at each end. Radula ( Fig. 5E–G ) with numerous indistinct, tubular, and forwardly curved teeth; tooth base slightly wider than free end, forming blunt cusp with a canalicular depression. Digestive tube ( Fig. 6C ) with buccal bulb possessing homogeneously distributed intrinsic muscles, muscle bundles not easily individualized; radular sac with round end, slightly prominent relative to buccal bulb retractor muscles; pharynx narrow, originating at top of buccal bulb. Salivary glands latero-basal with dark ducts that penetrate short pharynx dorso-laterally and located distally to esophageal crop. Anterior intestine narrow for initial third, extending to twice its initial thickness near the C-shaped stomach; C-shaped stomach with delicate, transparent walls and a typhlosole towards the hindgut. Reproductive System ( Fig. 6 D–F ): ovariotestis with single cluster of follicles and slender hermaphrodite duct; coiled in its middle portion; albumen gland developed, translucent near junction with ovispermoduct; fertilization complex ( Fig. 6F ) tubular, elongated at end proximal to the hermaphrodite duct and bent upon itself in the mid-region, which is thicker and lengthened again at its terminal end. Ovispermoduct well developed, translucent, with clear visualization of prostate; vas deferens ( Fig. 6E ) emerging from prostate above the point of bifurcation of the bursa copulatrix duct, extends superficially along the penial complex to the epiphallus region, later detaching from the surface penetrating the phallus wall. Bursa copulatrix duct tubular with decreasing thickness towards the bursa and starting down the exterior of the vas deferens; bursa copulatrix globular. Penial complex tubular, with short muscular sheath, without differentiation of external areas; flagellum short, terminally attached to phallus retractor muscle.

Type material: Holotype: Brazil, Minas Gerais, Itacarambi, Cavernas do Peruaçu National Park , Vale dos Sonhos, between crevices of the calcareous stones, MNRJ 23623 , 1 specimen, H = 43mm, W = 18mm, December 2010, M.S. Pena, D.C. Souza, A. Suhett Cols . Paratypes: Same locality, MNRJ 23624 , 9 adults and 6 young preserved specimens, December 2010, M.S. Pena; D. Souza; A. Suhett Cols.; PARNA Cavernas do Peruaçu , Desenho’s Cave , MNRJ 23625 , 18 adults and 2 youngs, November 2010, M.S. Pena, C. Damasceno, D.C. Souza Cols.; PARNA Cavernas do Peruaçu, Rezar Cave, MCNRS 41956 , 41 adult shells, 2 young shells, February /2009, M.S. Pena, M. Carolina , L.Caldeira Cols .

Additional material examined: Brazil, Minas Gerais, Itacarambi , PARNA Cavernas do Peruaçu, Vale dos Sonhos , Col.Mol. MCNPUC 340, 21 shells, January 2022, M.S. Pena, A. Vasconcelos Cols .; PARNA Cavernas do Peruaçu, Bonita Cave , Col. Mol. MCNPUC 218, 25 shels, November 2010, M.S. Pena, C. Damasceno, D.C. Souza Cols .; PARNA Cavernas do Peruaçu, Vale dos Sonhos , Col.Mol. MCNPUC 540, 20 shells, January 2022, M.S. Pena; A. Vasconcelos, J. Silva Cols .; PARNA Cavernas do Peruaçu, Carlúcio’s Cave trail, Col. mol. MCNPUC 579, 3 adults specimens, December 2022, J.S. Silva, M.S. Pena, I.S. Silva Cols .

Etymology: the new species is named in tribute (in memoriam) to Dr. Arnaldo C. dos Santos Coelho, an eminent malacologist of Museu Nacional, Rio de Janeiro.

Figures

Figure 5. Kora arnaldoi sp. nov.: (A) shell frontal; (B) dorsal view; (C) protoconch; (D) jaw; (E–G) radula, including in detail the canalicular groove. Scale bars: A–B = 5mm, C = 1 mm, D = 200 µm, E–F = 50 µm, G = 20 µm.

Figure 6. Kora arnaldoi sp. nov.: (A) pallial roof; (B) mantle edge; (C) digestive system; (D) reproductive system; (E) detail showing the vas deferens; (F) detail showing the fertilization complex. (AG) Albumen gland, (BC) bursa copulatrix, (BD) bursa duct, (FC) fertilization complex, (HD) hermaphrodite duct, (IL) inner lobe, (Ki) Kidney, (OL) outer lobe, (OV) ovariotestis, (Ovd) oviduct, (Pe) pericardium, (Pn) pneumostome, (Pr) prostate, (PV) pulmonary vein, (RE) rectum, (RN) radular nucleus, (SG) salivary gland, (ST) stomach, (VD) vas deferens. Scale bars: 2 mm.