Dadagulella browni semulikiensis, 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: 14

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Dadagulella browni semulikiensis

subsp. nov

Dadagulella browni semulikiensis   subsp. nov

Figs 22 View Figs 6-26 , 55 View Figs 51-64 , 84 View Fig ; Table 1 View Table 1


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. GoogleMaps   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.


SHELL ( Figs 22 View Figs 6-26 , 55 View Figs 51-64 ). 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.


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.


Naturhistorisches Museum, Wien


Universität Zürich