Dadagulella minareta, Rowson & Tattersfield, 2013

Rowson, Ben & Tattersfield, Peter, 2013, Revision of Dadagulella gen. nov., the “ Gulella radius group ” (Gastropoda: Streptaxidae) of the eastern Afrotropics, including six new species and three new subspecies, European Journal of Taxonomy 37, pp. 1-46 : 18-19

Dadagulella minareta sp. nov.

urn:lsid:zoobank.org:act:6AF1E4AF-D1D2-4C5A-9FCA-AC5B15A07204

Figs 30 , 50 , 58 , 84 ; Table 1

Etymology

From English ‘minaret’, the tower of a mosque; Latinized by the addition of the feminine ending ‘- a ’; used as a noun in apposition.

Type material examined

TANZANIA: holotype NMW.Z.2003.001.00010 : 1 ad., Kimboza Forest Reserve (7.01°S, 37.78°E), Uluguru Mts, Morogoro District, lowland forest on limestone, approx. 300 m alt., leg. BR, PT, MBS & CFN, 5 Feb. 2003 . Paratype NMW. Z.2003.001.00011: 1 ad., data as holotype. Paratypes NMW. Z.2003.001.00012: 3 ads, data as holotype. Paratype NMW. Z.2003.001.00013: 1 ad., data as holotype. Paratype MRAC. MT.803795: 1 ad., data as holotype. Paratype NHMUK.20120260: 1 ad., data as holotype. Paratype NMK: 1 ad., data as holotype. Paratypes NMT: 2 ads, data as holotype. Paratype NMSA. L 863/ T 3062: 1 ad., data as holotype. Paratype RMNH.288088: 1 ad., data as holotype.

Other material examined

TANZANIA: NMW. Z.2003.001.00014: 1 juv., data as holotype. NMW. Z.2004.016.00008: 2 ads, Kanga Forest Reserve (6.01° S, 37.72° E), Nguru Mts, Mvomero District, lowland forest at approx. 450 m alt., leg. BR, PT & CFN, 26 Jun. 2004. NMW. Z.1995.016.00012: 4 ads, 1 juv. Pugu Forest (6.89° S, 39.09° E), S of Dar es Salaam (site I), leg. PT, 6 Mar. 1995. The juv. in the Pugu lot may not be conspecific.

Description

SHELL ( Figs 30 , 50 , 58 ). Medium-sized (3.40 - 4.00 mm high x 1.80 - 2.00 mm wide), of 6.0 - 7.0 whorls. Ovate-acuminate, spire acuminate to coeloconoid (spire angle 48 - 63°).Apex sharply pointed. Embryonic whorls with fine regular radial striae; smoothly granulate where worn. Later whorls with relatively coarse, usually sinuous ribs (10 - 13 per mm on penultimate whorl). Sutures deep. Umbilicus narrowly open. Peristome complete or incomplete parietally. Outer palatal surface of aperture with a furrow-like depression corresponding to the palatal tooth. Dentition 5-fold to 7-fold, consisting of: one V-shaped parietal tooth; one bifid, slab-like, deeply in-running palatal tooth, not usually forming a parieto-palatal sinus; and two columellar teeth. The upper of these is large and characteristically squarish, running in to form a columellar baffle which is connected to it; the lower columellar tooth is a small in-running denticle. Additional teeth include an extra parietal tooth and/or one or two shallow columellar denticles. Juvenile shell ( Fig. 50 ) with 3-fold to 4-fold dentition: one very short parietal lamella; two basal teeth (or one bifid tooth); and one columellar tooth. Earlier basal and columellar teeth are retained.

CEPHALOPODIUM. Pale yellow, with apricot tentacle retractors.

SALIVARY GLANDS. United, soft, not tumid, elongate, Y-shaped; each duct leaving at the apex of the lobe and evenly thick throughout.

RADULA. Not successfully prepared.

GENITALIA. Vas deferens thickened prior to insertion on penis but apparently without diverticulum. Penial sheath absent but with a thin sheath-like layer contiguous with wall of lower penis. Interior of penis with weak radial pilasters and small rhombic pads. Apical part of penis with a broad “scoop” with microscopically serrated tip, but without large hook. Elsewhere in penis a single longitudinal row of short, simple hooks mounted on rhombic pads.

Range and habitat

In forest at the type locality and in Pugu Hills Nature Reserve, both in the eastern Tanzanian lowlands, and in lowland forest on Mt. Kanga in the Nguru Mts.

Remarks

The dentition, most noticeably the squared-off shallow columellar tooth that runs in to connect with the baffle, readily distinguishes this species from D. ecclesiola sp. nov. (which also occurs at Kimboza) and D. r. radius comb. nov. (which also occurs at both Kimboza and Pugu). It also distinguishes it from D. cuspidata ( Verdcourt, 1962) comb. nov., with which it shares the strong upper columellar tooth and fine regular radial striae on the embryonic whorls. It differs from D. cresswelli sp. nov., with which it shares the furrow-like depression on the outer palatal surface, in dentition and in having stronger ribs.

Figures

Figs 27-35. Adult shells of Dadagulella gen. nov. species. 27. D. delgada (Muratov, 2010) comb. nov., syntype, Cabo Delgado (after Muratov 2010). 28. D. ecclesiola sp. nov., holotype, Kimboza. 29. D. cresswelli sp. nov., holotype, Ngorongoro. 30. D. minareta sp. nov., holotype, Kimboza. 31. D. cuspidata (Verdcourt, 1962) comb. nov., holotype, Shume. 32. D. pembensis sp. nov., holotype, Ngezi. 33. D. nictitans (Rowson & Lange, 2007) comb. nov., holotype, Macha. 34. D. frontierarum sp. nov., holotype, Mtai. 35. D. delta sp. nov., holotype, Mwanihana.

Figs 43-50. Juvenile shells of Dadagulella gen. nov. species, with dentition emphasized in basal view including earlier dentition visible through the shell. 43-45. D. radius radius, Mbudya I. 46. D. pembensis sp. nov., Ngezi. 47-48. D. browni browni, Mwanihana. 49.? D. ecclesiola sp. nov., Kimboza. 50. D. minareta sp. nov., Kimboza.

Figs 51-64. Apertures of adult shells of Dadagulella gen. nov. species (not to scale). 51. D. radius calva, lectotype, Taru Desert. 52. D. radius radius, lectotype, Shimba Hills. 53. D. radius radius, Amboni. 54. D. browni mafiensis subsp. nov., holotype, Mlula. 55. D. browni semulikiensis subsp. nov., holotype, Semuliki NP. 56. D. ecclesiola sp. nov., holotype, Kimboza (two views of shell showing basal tooth only visible when shell angled). 57. D. cresswelli sp. nov., holotype, Ngorongoro. 58. D. minareta sp. nov., holotype, Kimboza. 59. D. cuspidata comb. nov., holotype, Shume (note shell angled slightly differently to that in Fig. 31). 60. D. pembensis sp. nov., holotype, Ngezi. 61. D. frontierarum sp. nov., holotype, Mtai. 62. D. minuscula minuscula, lectotype, Nzwani. 63. D. minuscula minuscula, paralectotype, Nzwani. 64. D. minuscula mahorana subsp. nov., holotype, Mayotte.

Fig. 84. Distribution of Dadagulella gen. nov. species, based on published records and material examined here (for additional records of D. meredithae comb. nov. in northern Malawi see van Bruggen 2000). The inset on the left corresponds to the map on the right.