Dadagulella browni subsp. semulikiensis Rowson & Tattersfield 2013, subsp. nov
Creators: name: Rowson, Ben
name: Tattersfield, Peter
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Streptaxidae
Dadagulella
Dadagulella browni
Dadagulella browni semulikiensis

description: Dadagulella browni semulikiensis subsp. nov
Figs 22, 55, 84; Table 1
Etymology
From Semuliki.
Type material examined
UGANDA: holotype NMW.Z.1997.009.00004: 1 ad., Semuliki National Park (00.82°N, 30.16°E), Bwamba County, Bundibugyo District, lowland Guineo-Congolian rainforest (site IIR), approx. 760 m alt., leg. PT & J.A. Allen, 14 Jul. 1996. Paratype NMW. Z. 1997.009.00005: 1 ad., data as holotype.
Other material examined
UGANDA: NMW. Z.1997.009.00006: 1 juv., data as holotype.
Description
SHELL (Figs 22, 55). Small (3.20 - 3.30 mm high x 1.90 mm wide), of 6.0 - 6.5 whorls. Ovate-acuminate, spire broadly acuminate (spire angle around 67°). Apex pointed. Embryonic whorls smoothly granulate. Later whorls with relatively coarse ribs (around 12 per mm on penultimate whorl). Sutures relatively shallow. Umbilicus closed. Peristome complete. Outer palatal surface of aperture with a depression corresponding to the palatal tooth, and another much weaker one corresponding to the basal tooth. Dentition 8-fold, consisting of: one lamella-like parietal tooth and one additional parietal denticle; one slab-like palatal tooth, forming a long, narrow parieto-palatal sinus; two basal denticles; a deepset columellar baffle and two shallower columellar denticles. Juvenile shell with 3-fold dentition: one parietal lamella; one bifid basal tooth; and one baso-columellar tooth. Anatomy unknown.
Range and habitat
Lowland Guineo-Congolian forest at the type locality in the valley of the Albertine Rift.
Remarks
This subspecies is very similar to D. b. browni comb. nov. and, if found together, the two might not at first glance be distinguished. However, D. b. semulikiensis subsp. nov. is approximately 10% taller and wider, has shallower sutures and a more complete peristome. Its parieto-palatal sinus is longer and narrower than that of D. b. browni comb. nov., and does not widen appreciably towards its inner end. The type localities of D. b. browni comb. nov. and D. b. semulikiensis subsp. nov. are over 3000 km apart, in very different biogeographic and climatic regions. Although several snail species are known to range between South and East Africa, most are either species of the coastal strip, or are widely distributed throughout the entire area. Dadagulella gen. nov. has not been recorded from much of the intervening area of East Africa and is represented in the Albertine Rift otherwise only by D. selene (van Bruggen & Van Goethem, 1999) comb. nov. It remains possible that the Semuliki population has descended from D. b. browni comb. nov., introduced by man from Tanzania or further to the south, and that the morphological differences are mainly ecophenotypic. However, in the light of these differences and the great geographic separation, we treat it as a subspecies of D. browni comb. nov. as we do with D. b. mafiensis subsp. nov.
description: Published as part of 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, pp. 1-46 in European Journal of Taxonomy 37 (37) on page 14, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/3806770