Dadagulella radius radius ( Preston, 1910 ) radius (Preston, 1910

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 : 6-9

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Dadagulella radius radius ( Preston, 1910 )

comb. nov.

Dadagulella radius radius ( Preston, 1910) comb. nov.

Figs 1-5 View Figs 1-5 , 9-20 View Figs 6-26 , 43-45 View Figs 43-50 , 52-53 View Figs 51-64 , 65 View Figs 65-68 , 69, 73 View Figs 69-76 , 77-78, 83-84 View Figs 77-83 View Fig ; Table 1 View Table 1

Ennea radius Preston, 1910: 529 , pl. VII, fig. 8.

Gulella radius – Verdcourt 1962: 13, 17,? not 22 (see D. radius calva below). — van Bruggen 1969: 71. — Verdcourt 1983: 234; 1985: 119, fig. 17; 1996: 136. — Tattersfield 1998a: 83; 1998b: 37. — Verdcourt 2000: 415. — van Bruggen 2000: 233. — Lange & Mwinzi 2003: 64-66. — Verdcourt 2006: 48. — Rowson 2007a: 441-442, fig. 56 (not fig. 54). — Rowson & Lange 2007: 31. — Muratov 2010: 277. — Rowson et al. 2010b: 28-29, in part. — Ndalila 2011: 24.

Ennea radius – Richardson 1988: 26.

Type material examined

KENYA: lectotype (here designated) MRAC. I17592 View Materials : 1 ad., “Shimbi Hills, British East Africa”, standing as “ radius ”, labelled “ex Putzeys-Musée, 1935”, “type” and apparently the shell figured in Preston (1910: pl. VII, fig. 8). Verdcourt (1985) wrote that a second shell from Shimbi in the NHMUK type collection could not be located at that time. We too failed to trace this specimen. Van Bruggen (1969) referred to two other NHMUK shells from Gazi as “ paratypes ”, presumably because they were labelled as such. However, Gazi (4.42°S, 39.50°E) is around 30 km from the type locality of Shimbi (Shimba) Hills (4.25 oS, 39.38 oE), and Preston (1910) distinguished between the two localities elsewhere in his paper. Thus it cannot be assumed that Gazi material has type status.

Other material examined

KENYA: NMW.1955.158.25050: 3 ads, 7 juvs, Gazi, standing as “ radius ”. RMNH.MOL.273272: 1 ad., Gazi, standing as “ radius ”. RMNH.MOL.273826: 1 ad., near Mombasa (approx. 4.04°S, 39.66°E), amongst river debris, Sep. 1987. NMW.Z.1990.067.00001: 1 ad., Arabuko-Sokoke Forest (3.32°S, 39.87°E), 20 km SW of Gedi, Brachystegia Benth. woodland on sandy soil with some leaf litter, leg. MBS, 12 Aug. 1989. NMW.Z.2012.042.00002: 2 ad., Diani Beach (4.27°S, 39.59°E), south of Mombasa, under deep mixed broadleaf litter, 18 m alt., leg. P. L. Cresswell, 24 Apr. 1997. NHMUK.1911.10.12.146-147: 2 ads, Gazi, standing as “ radius ”.

TANZANIA: NMW.Z.2009.013.00226: 2 ads, Jozani Forest Reserve (6.23°S, 39.42°E), Unguja I., Zanzibar, leg. BR, B.H. Warren, & CFN, 5 Feb. 2009. NMW.Z.2004.014.00023: 10 ads, 1 juv., several in poor condition, Jozani Forest Reserve, Unguja I., Zanzibar, leg. PT, MBS, & CFN, 11-12 Mar. 2000. NMW.Z.2003.001.00006: 2 ads, Mkungwe Forest Reserve (6.90°S, 37.91°E), Uluguru Mts, Morogoro District, submontane forest, approx. 900 m alt., leg. BR & CFN, 7 Feb. 2003. NMW.Z.2003.001.00007: 1 ad., 1 juv., 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. NMW.Z.2007.012.00001: 1 ad., Pugu Hills Nature Reserve (6.89°S, 39.09°E), SE of Dar es Salaam, leg. CFN, Jan. 2007 (sequenced by Rowson et al. 2010a as “ Gulella radius ”). NMT.2000/0130: 6 ads, 6 juvs Mbudya I. (6.66°S, 39.25°E), Dar es Salaam, leg. CFN & NMT team, 14 May 1998. NMW.Z.1995.016.00005: 3 ads, Kiono Forest (6.15°S, 38.59°E), NW of Dar es Salaam (site III), leg. PT, 5 Mar. 1995. NMW.Z.1995.016.00006: 1 ad., Pugu, S of Dar es Salaam (site II), leg. PT, 6 Mar. 1995. NMW.Z.1995.016.00007: 2 ads, Pugu Forest, S of Dar es Salaam (site I), leg. PT, 6 Mar. 1995. NMW.Z.1995.016.00008: 1 ad., Amboni caves and Mkulumuzi Gorge (5.06°S, 39.05°E), near Tanga (site I), leg. PT, 3 Mar. 1995. NMW.Z.1995.016.00010: 3 ads, 2 juvs, Amboni, near Tanga (site I), leg. PT, 3 Mar. 1995. NMW.Z.1995.016.00009: 2 ads,Amboni, near Tanga (site III), leg. PT, 3 Mar. 1995. NMW.Z.1995.016.00011: 6 ads, Amboni, near Tanga (site II), leg. PT, 3 Mar. 1995. NMW.Z.2003.074.00005: 1 ad., Kwamgumi Forest Reserve (4.94°S, 38.75°E), East Usambara Mts, Muheza District, lowland forest at approx. 350 m alt., leg. Frontier Tanzania, 4 Dec. 1996. NMW.Z. 2003.074.00006: 1 ad. in poor condition, Mtai Forest Reserve (4.87°S, 38.77°E), East Usambara Mts, Muheza District (plot 73), riverine forest at 200 m alt., leg. Frontier Tanzania, 23 Jan. 1996.


SHELL ( Figs 1-5 View Figs 1-5 , 9-20 View Figs 6-26 , 43-50 View Figs 43-50 , 52-53 View Figs 51-64 ). Very variable in size, shape and dentition, small to large (2.80 - 4.60 mm high x 1.60 - 2.44 mm wide), of 6.0 - 7.0 whorls. Ovate-acuminate, spire narrowly to broadly acuminate (spire angle 55 - 70°). Apex pointed. Embryonic whorls smoothly granulate. Later whorls with relatively coarse and few ribs (7 - 16 per mm on penultimate whorl). Sutures relatively deep. Umbilicus closed or narrowly open. Peristome complete or (more often) incomplete parietally. Outer palatal surface of aperture with a depression corresponding to the palatal tooth and sometimes another one corresponding to the basal tooth. Dentition 5-fold to 7-fold, consisting of at least: one lamella-like parietal tooth; one slab-like palatal tooth, often bifid; one basal denticle; one shallow columellar denticle (very weak in some cases) and one deep-set columellar baffle, always visible. Parieto-palatal sinus, if present, broad, seldom narrow or parallel-sided. Neither the columellar baffle nor basal denticle were mentioned in Preston’s (1910) original description, although both are clearly visible on the lectotype which is apparently the originally figured specimen. We assume this to have been a lapsus. One or two additional columellar denticles may be present (e.g. Figs 12, 14, 15 View Figs 6-26 ). Juvenile shells ( Figs 43-45 View Figs 43-50 ) with 3-fold dentition: one parietal lamella; one bifid basal tooth; and one columellar tooth or thickening. Some earlier teeth are retained in some juveniles and even adults (e.g. some specimens from Jozani).

CEPHALOPODIUM. Pale cream or yellow, with apricot to orange tentacle retractors and often with brown speckles on the mantle.

SALIVARY GLANDS ( Fig. 69 View Figs 69-76 ). United, soft, not tumid, elongate, bilobed to nearly Y-shaped; each duct leaving at the whitened apex of the lobe and evenly thick throughout.

RADULA ( Fig. 65 View Figs 65-68 ). With a unicuspid central tooth and around 13 laterals in each half-row, diminishing gradually in size laterally. All laterals bicuspid or tricuspid, with outer cusps much smaller than inner cusps.

GENITALIA ( Figs 73 View Figs 69-76 , 77, 83 View Figs 77-83 ). Vas deferens appearing thickened prior to insertion on penis but actually with a short, broad parallel diverticulum. Penial sheath absent but with a thin sheath-like layer contiguous with walls of lower penis. Interior of penis with weak radial pilasters and small rhombic pads, sometimes with a longitudinal pilaster or short, rounded and weakly chitinized lobe. Apical, muscular part of penis with a single large hook, associated with a “scoop” with microscopically serrated tip. Elsewhere in penis, a single longitudinal row of short, simple hooks mounted on rhombic pads. “Spermatophore” (see Discussion) present in penis and vagina of one Amboni specimen; “spermatophore” tail, apparently attached to penis wall, present in penis of one Pugu specimen.

Range and habitat

Eastern Kenya and eastern Tanzania, including Unguja ( Zanzibar) island. Apparently replaced by other Dadagulella gen. nov. species on Pemba island and in some lowland areas and montane forests, and by D. browni comb. nov. s.l. in Tanzania from around 7.8°S southwards. Dadagulella r. radius comb. nov. is sympatric with other Dadagulella gen. nov. species at Kwamgumi, Pugu and Kimboza [it has also been recorded from Kimboza by Verdcourt (2006: 48)]. The records are mainly from forest and other wellvegetated habitats; Verdcourt (2000) suggested the habitat was “woodland/forest”. Lange & Mwinzi (2003) found D. radius comb. nov. across several forest types at Arabuko-Sokoke, but Ndalila (2011) found only three specimens in the Shimba Hills, all in scrub and grassland rather than forest.


This appears to be the most widespread and variable species of Dadagulella gen. nov. In this we concur with van Bruggen (1969) and Verdcourt (1985) that D. radius comb. nov. is a species variable enough to include shells as different as the lectotype ( Figs 1-5 View Figs 1-5 , 11 View Figs 6-26 ) and those from Diani Beach ( Fig. 14 View Figs 6-26 ). We retain one such extreme form, subsequently described by Connolly (1922) as Gulella calva Connolly, 1922 , as a subspecies of D. radius comb. nov. (see below) but we refrain from describing additional subspecies since these forms are not obviously geographically isolated (e.g. at Amboni, Fig. 15 View Figs 6-26 ) and occur throughout the geographical range of the species. The variation between them often appears continuous rather than discrete (e.g. compare Figs 17-20 View Figs 6-26 , each from a similar latitude and arranged in order from W to E). Furthermore, some variability is often present at a single locality, e.g. at Gazi (compare Figs 12 and 13 View Figs 6-26 ). Despite this, D. radius comb. nov. s.l. differs from other similar, lowland species as follows. It differs from D. browni comb. nov. s.l. in never having either an additional parietal denticle or two basal denticles, and in normally having a broader (or no) parieto-palatal sinus. It differs from D. delgada ( Muratov, 2010) comb. nov. in lacking the flaring, lamella-like ribs and nearly always having a more broadly acuminate spire. It differs from D. ecclesiola sp. nov. in not having the basal denticle hidden behind the palatal tooth, in having at least one shallow columellar tooth, and in having a broader (or no) parieto-palatal sinus. The distinction between D. radius comb. nov. s.l. and D. minuscula comb. nov. of the Comoros, with which it was compared by Preston (1910), is discussed under the latter species.


Musée Royal de l’Afrique Centrale


Natural History Museum, London


Naturhistorisches Museum, Wien


National Museum of Natural History, Naturalis


Manchester Banksian Society


Embrapa Agrobiology Diazothrophic Microbial Culture Collection


Clifton College














Dadagulella radius radius ( Preston, 1910 )

Rowson, Ben & Tattersfield, Peter 2013

Ennea radius

Richardson C. L. 1988: 26

Gulella radius

Ndalila M. 2011: 24
Muratov I. V. 2010: 277
Rowson B. & Warren B. H. & Ngereza C. F. 2010: 28
Rowson B. 2007: 441
Rowson B. & Lange C. N. 2007: 31
Verdcourt B. 2006: 48
Lange C. N. & Mwinzi M. 2003: 64
Verdcourt B. 2000: 415
Bruggen A. C. van 2000: 233
Tattersfield P. 1998: 83
Tattersfield P. 1998: 37
Verdcourt B. 1985: 119
Verdcourt B. 1983: 234
Bruggen A. C. van 1969: 71
Verdcourt B. 1962: 13

Ennea radius

Preston H. B. 1910: 529