Dadagulella browni subsp. browni browni (van Bruggen 1969, comb. 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 browni (van bruggen, 1969)

description: Dadagulella browni browni (van Bruggen, 1969) comb. nov.
Figs 23-26, 47-48, 71, 74, 82, 84; Table 1
Gulella browni van Bruggen, 1969: 69-71, figs 25-26.
Gulella browni – van Bruggen & Appleton 1977: 31-32. — Aiken 1981: 321-323, fig. 5. — Richardson 1988: 60. — Verdcourt 1990: 349. — van Bruggen & Van Goethem 1999: 40. — van Bruggen 2000: 233-234. — Herbert & Kilburn 2004: 212. — Rowson & Lange 2007: 31. — Muratov 2010: 277.
“a closely related species from Zululand” – Verdcourt 1985: 119.
Gulella cf. radius – Tattersfield et al. 2006: 52, 54, 58.
Type material examined
SOUTH AFRICA: holotype RMNH.MOL.54894: 1 ad., Lake Sibayi (approx. 27.34°S, 32.71°E), KwaZulu-Natal, dune forest on the east shore, leg. D.S. Brown, 12 Jun. 1966 (examined digital photograph only).
Other material examined
TANZANIA: NMW.Z.2003.001.00008: 6 ads, 5 juvs, Mt. Mwanihana Forest Reserve (7.82°S, 36.83°E), Udzungwa Mts National Park, Kilombero District, lowland forest at approx. 600-900 m alt., leg. BR, PT, MBS & CFN, 29 Jan. 2003. NMW.Z.2003.001.00009: 4 ads, data as previous but 700 m alt. NMW.Z.1997.007.00003: 5 ads, 2 juvs, Mzelezi Forest Reserve (8.79°S, 36.72°E), Mahenge Mts, Ulanga District, forest on limestone, approx. 645 m alt., leg. PT, MBS & CFN, 6 Feb. 1997. NMW.Z.1997.007.00004: 1 ad., data as previous. NMW.Z.1997.007.00005: 2 ads, 6 juvs, data as previous.
MOZAMBIQUE: NMW.Z.2012.040.00001: 2 ads, Pomene Bay, Inhambane Province, near lighthouse S of old hotel (22.9417°S, 35.5913°E), degraded dune forest, in leaf-litter, leg. D. Herbert, Oct. 2002 (ex NMSA.L5797). NMSA.L5797: 2 ads, data as previous.
SOUTH AFRICA: NMW.Z. 2012.040.00002: 3 ads, Kosi Bay mouth, KwaZulu-Natal (26.89°S, 32.88°E), dune forest, in sandy leaf-litter, leg. D. Herbert & L. Davis, “11-41”, 13 Oct. 2011 (ex NMSA. W8517). NHMUK.20110173: 2 ads, Lake Sibaya area of Tongaland (approx. 27.35°S, 32.67°E), Zululand, S. Africa, leg. C.C. Appleton, Dec. 1972 - Nov. 1973.
Description
SHELL (Figs 23-26, 47-48). Small (2.60 - 3.20 mm high x 1.60 - 1.90 mm wide), of 5.5 - 6.0 whorls. Ovateacuminate, spire broadly acuminate (spire angle 66 - 76°). Apex pointed. Embryonic whorls smoothly granulate. Later whorls with relatively coarse ribs (11 - 15 per mm on penultimate whorl). Sutures relatively shallow. Umbilicus closed or narrowly open. Peristome incomplete parietally. Outer palatal surface of aperture with a depression corresponding to the palatal tooth and another much weaker one corresponding to the basal tooth. Dentition 7-fold to 8-fold, consisting of: one lamella-like parietal tooth and (almost always) one additional parietal denticle; one slab-like palatal tooth, forming a narrow parieto-palatal sinus; two basal denticles; a deep-set columellar baffle, sometimes folded, and one or two shallower columellar denticles. Dentition of 8-fold individuals alternatively recognisable as 7-fold, depending on the interpretation of the columellar and parietal denticles (van Bruggen 1969). Juvenile shells of D. browni comb. nov. were not known to van Bruggen (1969, 2000). Herbert & Kilburn (2004) describe them simply as dentate, but with dentition different from that of the adult. Juveniles from southern Tanzania (Figs 47-48) have dentition similar to, but weaker than, juveniles of D. r. radius comb. nov. (Figs 43-45).
CEPHALOPODIUM. Pale cream, with pink-orange tentacle retractors and a few purple-brown speckles in the mantle.
SALIVARY GLANDS (Fig. 71). United, soft, not tumid, elongate, bilobed; each duct leaving at the whitened apex of the lobe and evenly thick throughout.
RADULA. Described and figured by Aiken (1981) as having a unicuspid, ‘heart-shaped’ central tooth and nine laterals in each half-row, of which at least the inner six are tricuspid, diminishing gradually in size laterally. The outer cusps of most teeth are smaller than the inner cusp. According to Aiken (1981) the teeth are flexible when pressed by a cover slip and there are 47 rows.
GENITALIA (Figs 74, 82). Upper parts of spermoviduct not recovered. Vas deferens appearing thickened prior to insertion on penis but actually with a very short, broad parallel diverticulum. Penial sheath absent. Interior of penis with weak radial pilasters. Apical, muscular part of penis with a single large hook, associated with a spatulate “scoop” with microscopically serrated tip. Elsewhere in penis, a single longitudinal row of short, simple hooks.
Range and habitat
Coast of north-eastern South Africa: dune forest, coastal forest and bush; also central Mozambique: high forest in Chiluvo [Xiluvo] hills (19.24°S, 34.06°E) at 700 ft (approx. 213 m) elevation (van Bruggen 1969; van Bruggen & Appleton 1977; Herbert & Kilburn 2004). Also in lowland forest, up to 900 m, in southern Tanzania, as far north as 7.8°S.
Remarks
We agree with van Bruggen (1969) that the complex dentition of D. browni comb. nov. s.l. separates it from D. radius comb. nov. s.l., which never seems to have 8-fold dentition, in particular the extra parietal and basal denticles. The shells of D. browni comb. nov. s.l. are also much smaller, less elongate (i.e. have a lower height/width ratio), and have a much narrower and more horizontal parieto-palatal sinus than is usual for D. radius comb. nov. s.l. Although some specimens of D. r. radius comb. nov. approach D. browni comb. nov. s.l. in one or more of these respects (e.g. Figs 10, 14, 17) all can be readily assigned to one or the other and the type specimens are morphologically quite different (Figs 1-5, 11, 52 vs. Fig. 26). Material intermediate between D. browni comb. nov. and D. radius comb. nov. might be expected in the intervening area of southern Tanzania or northern Mozambique. However, all the relevant southern Tanzanian material here (e.g. from Mafia and Mahenge) is closer to D. browni comb. nov. s.l. in dentition and other aspects. A recent survey in northern Mozambique (Muratov 2010) encountered only D. delgada comb. 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 pages 11-13, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/3806770