Dadagulella meredithae (van Bruggen, 2000 ) 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 : 26-27

Dadagulella meredithae (van Bruggen, 2000) comb. nov.

Figs 37 , 84 ; Table 1

Gulella meredithae van Bruggen, 2000: 226-232 , figs 1-7.

“…an as yet unidentified species from Malawi ” – van Bruggen & Meredith 1984: 165.

Gulella meredithae – Rowson & Lange 2007: 31.

Type material examined

MALAWI: holotype RMNH.59399 : 1 ad., Nyika National Park (approx. 10.6°S, 33.8°E), Rumphi District, Juniper Forest , approx. 2100 m alt., leg. H.M. Meredith, 16 Sep. 1983.

Other material examined

None.

Description

SHELL ( Fig. 37 ). Small (2.30 - 3.10 mm high x 1.40 - 1.60 mm wide), of 5.5 - “<6” whorls. Ovate-acuminate, although spire (spire angle 58 - 77°) less acuminate than in other Dadagulella gen. nov species. Apex rounded (in holotype) to weakly pointed. Embryonic whorls smoothly granulate. Later whorls with very fine, very numerous ribs (about 27 per mm on penultimate whorl). Sutures of intermediate depth. Umbilicus closed or nearly so. Peristome incomplete parietally. Outer palatal surface of aperture with a depression corresponding to the palatal tooth. Dentition 3-fold to 4-fold, consisting of at least: one lamella-like parietal tooth; one slab-like palatal tooth, not forming a parieto-palatal sinus; and a mammillate columellar baffle. Additional teeth limited to a shallow, weak columellar swelling. Juvenile shells with 2-fold to 3-fold dentition: one parietal tooth; one columellar tooth; and usually one basal tooth (termed labral by van Bruggen 2000). Van Bruggen (2000) showed that earlier sets of dentition are visible through the shells of some transparent juveniles, even in the preceding whorls, suggesting slow or no resorbtion. Anatomy unknown.

Range and habitat

Montane forest (above 1500 m to around 2450 m) in northern and central Malawi, and adjacent part of Zambia (Chowo Forest). Van Bruggen (2000) suspected it to range into parts of Tanzania adjoining northern Malawi.

Remarks

This species is distinctive in its small size, very fine, numerous ribs, and dentition. It differs from D. radius comb. nov. s.l. and D. browni comb. nov. s.l. in the lack of a basal tooth or denticle. The apex is rounded in the holotype but more conical in paratypes figured by van Bruggen (2000).

Figures

Figs 36-40. Adult shells of Dadagulella gen. nov. species. 36. D. selene (van Bruggen & Van Goethem, 1999) comb. nov., holotype, Virunga NP (after van Bruggen & Van Goethem 1999). 37. D. meredithae (van Bruggen, 2000), holotype, Nyika NP. 38. D. minuscula minuscula (Morelet, 1877), lectotype, Nzwani. 39. D. minuscula minuscula, paralectotype, Nzwani. 40. 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.