125,388 research outputs found
Dadagulella pembensis Rowson & Tattersfield 2013, sp. nov.
No full textDadagulella pembensis sp. nov. urn:lsid:zoobank.org:act: 4442210F-A097-400D-B34F-96 A 4 B 7677CE7 Figs 32, 46, 60, 66-68, 70, 75, 79-80, 84; Table 1 ““ Gulella ” radius (Preston, 1910) ” – Rowson et al. 2010 b: 9-10, 28-29, figs 60-61. Etymology From Pemba Island, with the final ‘a’ elided for euphony. Type material examined TANZANIA: holotype NMW.Z.2009.013.00227: 1 ad., Ngezi Forest Reserve (4.94°S, 39.69°E), Pemba I., Zanzibar, dry forest on dark, sandy soil on coral rag on Tondooni peninsula within reserve, leg. BR, B. H. Warren & CFN, 7 Feb. 2009; fig. 60 in Rowson et al. (2010 b). Paratypes NMW. Z.2009.013.00228: 2 ads, data as holotype. Paratypes MRAC. MT.803796-7: 2 ads, data as holotype. Paratypes NHMUK.20120261: 2 ads, data as holotype. Paratypes NMK: 2 ads, data as holotype. Paratypes NMT: 2 ads, data as holotype. Paratypes NMSA. L 8694/ T 3063: 2 ads, data as holotype. Paratypes RMNH. MOL.288090: 2 ads, data as holotype. Other material examined TANZANIA: NMW. Z.2009.013.00229: 15 juvs, data as holotype; one figured as fig. 61 in Rowson et al. (2010 b). NMW. Z.2009.013.00230: 3 ads, near Chwaka (5.39° S, 39.77° E), Pemba I., Zanzibar, clove and fruit tree woodland on dark, sandy soil, leg. BR, B. H. Warren & CFN, 15 Feb. 2009. NMW. Z.2009.013.00231: 3 ads, Msitu Mkuu Forest Reserve (5.00° S, 39.83° E), Pemba I., Zanzibar, moist forest on dark (not sandy) soil on coral rag in high forest in north of reserve, leg. BR, B. H. Warren & CFN, 10 Feb. 2009. NMW. Z.2009.013.00232: 3 ads, Ngezi Forest Reserve, Pemba I., Zanzibar, dry forest and thicket on dark, sandy soil on coral rag on coast of Tondooni peninsula within reserve, leg. BR, B. H. Warren & CFN, 8 Feb. 2009. NMW. Z.2009.013: Many additional ads and juvs from the type locality and other sites on Pemba I., Feb. 2009; see table 2 of Rowson et al. (2010 b). Description SHELL (Figs 32, 46, 60). Large (4.80 - 5.50 mm high x 2.00 - 2.50 mm wide), of 6.5 - 7.5 whorls. Ovateacuminate, spire narrowly to broadly acuminate (spire angle 51 - 65°). Apex sharply pointed. Embryonic whorls smoothly granulate. Later whorls with relatively coarse ribs (12 - 15 per mm on penultimate whorl). Sutures shallow, shell appearing relatively straight-sided. Umbilicus closed or nearly so. Peristome complete, or incomplete parietally. Outer palatal surface of aperture with a depression corresponding to the palatal tooth and often another corresponding to the basal tooth. Dentition 6-fold, consisting of: one lamella-like parietal tooth; one slab-like palatal tooth, forming a parieto-palatal sinus; one basal denticle; a deep-set columellar baffle, sometimes folded, sub-bifid or sub-trifid; and two shallower, broad columellar denticles. Juvenile shells (Fig. 46) with 3-fold dentition, similar to some forms of D. r. radius comb. nov.: one parietal lamella; one basal tooth; and one columellar thickening. Earlier basal teeth are retained in juveniles. CEPHALOPODIUM. Pale yellow, with apricot to orange tentacle retractors. SALIVARY GLANDS (Fig. 70). United, soft, not tumid, elongate, Y-shaped; each duct leaving at the apex of the lobe and evenly thick throughout. RADULA (Figs 66-68). With a unicuspid central tooth and around 15 laterals in each half-row, gradually diminishing in size laterally. All laterals bicuspid, tricuspid, or quadricuspid, with outer cusps much smaller than inner cusps. Teeth delicate, short and flake-like at the ventral end of the radular ribbon. GENITALIA (Figs 75, 79, 80). 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 wall of lower penis. Interior of penis with weak radial pilasters and small rhombic pads. Apical, muscular part of penis with a single large hook, associated with a spatulate “scoop” with microscopically serrated tip. Elsewhere in penis, one or two longitudinal rows of short, simple hooks mounted on rhombic pads. “Spermatophore” (see Discussion) present in penis of two Ngezi specimens; partially digested remains in bursa of another. Range and habitat Pemba Island, Tanzania, where widespread in forest and other vegetated habitats. Remarks This species was discussed by Rowson et al. (2010 b), who suggested a thorough revision of the group to establish whether the Pemba populations were part of a variable D. radius comb. nov. or a subspecies or species endemic to Pemba. This uncertainty was incorporated into their conclusions on endemism on the island (Rowson et al. 2010 b: 28-29, 32). We find here that there is little or no overlap with D. radius comb. nov. s.l. or other species, so conclude that this is an island endemic, which we here name D. pembensis sp. nov. Like specimens of D. r. radius comb. nov. on the opposite mainland at Amboni (e.g. Figs 15, 53), D. pembensis sp. nov. is large and has a complex pattern of 6-fold dentition. However it is distinguishable from them by its even larger size, shallower sutures, and having on average an extra 0.5 whorls. It differs from D. minuscula mahorana subsp. nov. which has similar dentition, in its larger size, shallower sutures, and stronger and more widely spaced ribs.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 on pages 20-22, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/380677
Revision of Dadagulella gen. nov., the “Gulella radius group” (Gastropoda: Streptaxidae) of the eastern Afrotropics, including six new species and three new subspecies
No full textThe genus Dadagulella gen. nov. is described to include 16 species of small, dentate, ovateacuminate Afrotropical snails. An identification key is provided and biogeography, anatomy and systematics are discussed. The type species is the Kenyan D. radius (Preston, 1910) comb. nov., whose name has informally been used for part of the group in the past. Substantial intraspecific variation occurs in three species: D. radius itself, D. browni (van Bruggen, 1969) comb. nov. and D. minuscula (Morelet, 1877) comb. nov. (= Ennea fi scheriana Morelet, 1881) (non Gulella minuscula Emberton & Pearce, 2000) . We recognise subspecies within each of these: D.radius radius (Preston, 1910) comb. nov., D. r. calva (Connolly, 1922) comb. et stat. nov., D. browni browni (van Bruggen, 1969) comb. nov., D. b. mafi ensis subsp. nov., D. b. semulikiensis subsp. nov., D. minuscula minuscula (Morelet, 1877) comb. nov., D. m. mahorana subsp. nov. Six new Tanzanian species are described: D. cresswelli sp. nov., D. delta sp. nov., D. ecclesiola sp. nov., D. frontierarum sp. nov., D. minareta sp. nov., and D. pembensis sp. nov. The genus includes seven other previously described species: D. cuspidata (Verdcourt, 1962) comb. nov.; D. rondoensis (Verdcourt, 1994) comb. nov.; D. conoidea (Verdcourt, 1996) comb. nov.; D. selene (van Bruggen & Van Goethem, 1999) comb. nov.; D. meredithae (van Bruggen, 2000) comb. nov.; D. nictitans (Rowson & Lange, 2007) comb. nov.; and D. delgada (Muratov, 2010) comb. nov
Dadagulella cuspidata Rowson & Tattersfield 2013, comb. nov.
No full textDadagulella cuspidata (Verdcourt, 1962) comb. nov. Figs 31, 59, 84; Table 1 Gulella cuspidata Verdcourt, 1962: 3, 27-28, pl. 3, fig. 2. “ Gulella sp. nov. ” – Verdcourt 1958: 94, 100, fig. 10. Gulella cuspidata – van Bruggen 1969: 71. — Verdcourt 1983: 232. — Richardson 1988: 72. — Verdcourt 1996: 136. — Tattersfield 1998 b: 37. — Tattersfield et al. 1998: 135. — van Bruggen 2000: 233. — Verdcourt 2006: 46. — Rowson & Lange 2007: 31. — Muratov 2010: 277. Type material examined TANZANIA: holotype MRAC.792352: 1 ad., Worlds View, Shume, West Usambara Mts (4.70°S, 38.20°E), in rather dry evergreen forest, leg. B. & L. Verdcourt, Dec. 1956. Other material examined None. Description SHELL (Figs 31, 59). Large (4.30 - 4.80 mm high x 1.80 x 2.50 mm wide), of 7.75 whorls. Ovate-acuminate, spire coeloconoid (spire angle 58°). Apex sharply pointed. Embryonic whorls appear smooth but with fine regular radial striae. Later whorls with relatively few, coarse ribs (about 8 per mm on penultimate whorl). Sutures of intermediate depth. Umbilicus narrowly open. Peristome incomplete parietally. Outer palatal surface of aperture with a furrow-like depression corresponding to the upper palatal tooth. Dentition 6-fold (alternatively recognisable as 5-fold), consisting of: one lamella-like parietal tooth; two palatal teeth, the upper much larger and forming a parieto-palatal sinus; one basal, in-running tooth; and a strong, squarish columellar tooth, running in to form a columellar baffle which is connected to it. Juvenile shells and anatomy unknown. Range and habitat Elevation not stated but probably between 1500-2000 m at the type locality in northeastern Tanzania. Remarks This species differs from D. minareta sp. nov. in having two palatal teeth, in having a basal tooth, in the shape of the parietal tooth, and in size.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 on page 20, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/380677
Dadagulella cresswelli Rowson & Tattersfield 2013, sp. nov.
No full textDadagulella cresswelli sp. nov. urn:lsid:zoobank.org:act: B 3362D6 F- 2118 -4D1 D- 8 B 25-098 E 25 B 0 C 3 B 2 Figs 29, 57, 84; Table 1 Etymology After Pete Cresswell, who collected the specimen. Type material examined TANZANIA: holotype NMW. Z.2012.042.00001: 1 ad., Ngorongoro Crater, Arusha Region, crater rim on southeastern side, heavy rainforest leaf litter, leg. P. L. Cresswell, 2 Jun.1996. Other material examined None. Description SHELL (Figs 29, 57). Medium-sized (3.70 mm high x 1.80 mm wide), of 7.0 whorls. Ovate-acuminate, spire coeloconoid (spire angle 52°). Apex sharply pointed. Embryonic whorls smoothly granulate. Later whorls with relatively fine ribs (13 per mm on penultimate whorl). Sutures shallow. Umbilicus narrowly open. Peristome complete. Outer palatal surface of aperture with a very deep, long, furrow-like depression corresponding to the palatal tooth. Dentition 5-fold, consisting of: one V-shaped parietal tooth; one bifid slab-like palatal tooth, forming a clear parieto-palatal sinus, with the upper cusp projecting into the sinus; a deep-set columellar baffle and two shallower columellar denticles. Shells and anatomy of juveniles unknown. Range and habitat Forest at the type locality in northern Tanzania. The vegetation is presumably of a montane type, since the crater floor is above 1700 m while the rim rises to over 2400 m or higher. Remarks This species is distinctive in its deep, long furrow on the outer palatal surface in combination with the coeloconoid spire and dentition. D. minerata sp. nov. shares these features, but differs in having weaker ribs and less complex dentition. It is the only Dadagulella gen. nov. species thus far collected in the volcanic (as opposed to block-faulted) highlands of Tanzania or Kenya.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 on page 18, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/380677
Gulella nictitans B & Rowson & C & N & Lange 2007, sp. n.
No full textGulella nictitans sp. n. Figs 4–7, 14–19 Etymology: From Latin nictitans (winking); with reference to the parieto-palatal sinus that recalls a closed eye. Diagnosis: Shell small for the genus, distinctively ovate-biconical; sculptured with strong axial ribs; peristome complete, apertural dentition distinctive, arguably five-fold: a strong, palatally directed parietal lamella meeting a large palatal slab, the two almost meeting along a narrow parieto-palatal sinus, the other dentition consisting of three folds on the columella; embryonic shell finely granular; umbilicus closed. Description: Adult shell (Figs 4–7) small for the genus (height 3.6–3.9 mm, width 2.0– 2.2 mm), and ovate-biconical, of 5.5 whorls. Spire more conical than most other Gulella. Shell shape varies a little intraspecifically but other shell features almost constant. Penultimate whorl and body whorl together comprise about 67% of total shell height. Aperture (including peristome) comprises about 34% of total shell height. Peristome complete, thickened and reflected and flaring. Body whorl strongly constricted adjacent to the aperture, especially along the excision corresponding to the palatal slab, such that the palatal side of the body whorl is divided into two regions. Columella relatively straight but body whorl occludes any umbilicus, the visible suture being the junction of the body whorl and penultimate whorl. Apertural dentition well-developed, occluding much of the aperture, and consistently with five processes, although the three columellar processes are little more than folds on the columella and so the dentition could be considered less than five-fold.Apertural processes are as follows: (1) a large, thick, palatally directed and deeply entering parietal lamella projecting outwards a very short distance from the body whorl and corresponding to an outwardly and palatally directed V-shaped depression in the parietal callus; (2) a strong, slab-like palatal process, curved inwardly on the columellar side and nearly straight along its upper margin, and corresponding to a very long and deep excision on the palatal side of the body whorl; and (3–5) three slight, simple, and deeply set folds on the columella, the two upper folds being much smaller than the basal one. Resulting apertural dentition formula sensu Verdcourt (1962) can be given as 1; 1; 0; 3, or alternatively 1; 1; 0; 1(3). Parieto-palatal sinus narrow, tubular and directed palatally at an angle of 75–90° from the columella, almost closed in front by the near-meeting of the margins of the parietal lamella and palatal slab along a straight line, resulting in a conspicuous narrow slit. Parietal callus thick and clearly distinct from body whorl, being separated from it by a detectable groove. Outer columellar wall with a slight but long excision corresponding to the lowermost columellar fold. No sign of juvenile dentition in the single juvenile specimen (paratype 9) or inside the shells of dissected adults. Shell colourless and glassy, dirty white when corroded, with no obvious periostracum. Shell surface as follows: embryonic whorls smoothly, irregularly granular under a light microscope (60× magnification). Later whorls with major sculpture of strong, oblique, straight or slightly sinuous, regular axial ribs with sharply defined edges, interstices between ribs nearly smooth. On the holotype, ribs occur at a density of about 13 per mm (penultimate whorl) and about 12 per mm (body whorl). On palatal side of body whorl, ribs continue only as far as the long excision corresponding to the palatal slab, being replaced by much finer, irregular ribs beneath the excision. Finer, irregular ribs also replace the major axial ribs on the columellar side of the body whorl. Body colour: Alcohol-preserved specimens are unicolorous pale cream, without differently coloured tentacles, patterning on the mantle, etc. Salivary gland (Fig. 14): Single, 1.2 mm long, fragile, distinctively Y-shaped, with anterior portion of posterior half of gland produced anteriorly. Anterior duct exiting gland apically; posterior duct exiting from the apex of the posterior half of gland. Both salivary ducts evenly narrow throughout their length. Genitalia (Figs 15–19): Penis rather long (3.25 mm when straightened or 1.5 whorls when bent) without appendices. Apical part of vas deferens bound to penis by an extremely thin, transparent sheath contiguous with wall of penis basally. Vas deferens substantially thickened distally, entering penis subapically, with penial retractor muscle attaching to apical part of penis and to vas deferens near the entry point and thus effectively bifid. Penial retractor originating from the free muscle system and not from the body wall. Interior surface of penis (Fig. 15) consisting of soft structures and chitinous hooks (some highly modified) as follows. Apical part of penis: slightly constricted, with a single large (about 0.35 mm long), spatulate yellow-brown modified hook, its base embedded in fibres of penial retractor and projecting beyond constriction into main lumen of penis, with a row of thin extensions at its tip. This is flanked by two large (about 0.25 mm long) bifid yellow-brown hooks attached by very narrow bases. Main part of penis: dominated by a single central longitudinal blade-like pilaster, flanked by incomplete transverse ridges or septae and a single row of low, irregularly shaped pads bearing simple yellow-brown triangular hooks that vary little in size and shape (about 0.05 mm long). Basal part of penis: longitudinal pilaster, pads and septae interrupted, resulting in a more irregular surface, structures becoming very indistinct towards atrium. Total number of hooks in penis: 31. Albumen gland moderately sized and with a uniform structure of small and indistinct vesicles or acini. Hermaphroditic duct diverticulum (talon) enlarged, simple and not convoluted, not hidden within albumen gland. Bursa copulatrix (= gametolytic sac or spermatheca) small, ovoid, apparently empty, and attending albumen gland. Acini of oviductal gland elongate, flattened, large and distinct. Acini of prostate very indistinct. Vagina and atrium short, little muscularised. Holotype: KENYA: Taita Hills, Macha Forest Reserve (3°27'S: 38°22'E), leaf litter in indigenous forest at 1550 m altitude (site IB), leg. C.N. Lange, 27.ix.1998 (NMK). TABLE 2 Data on types of G. nictitans sp. n. All specimens are live-collected adults except where noted. Abbreviations: Ht – holotype, Pt – paratype, Acc. no. – accession number including museum acronym, H – height, W – width. Paratypes: Collection data for all paratypes same as holotype; all specimens except paratype 5 and paratype 9 are live-collected adults (Table 2). Other material examined: 9 additional specimens, as follows: KENYA: Taita Hills: 1 adult, Macha Forest Reserve (3°27'S: 38°22'E), leaf litter in indigenous forest at 1550 m altitude, leg. C.N. Lange, 27.ix.1998; 1 adult, Ndiwenyi Forest Reserve (3°26'S: 38°21'E), leaf litter in indigenous forest at 1580 m altitude, leg. C.N. Lange, 26.ix.1998; 6 adults, Yale Forest Reserve (3°24'S: 38°18'E), leaf litter in indigenous forest at 1900 m altitude, leg. C.N. Lange, 29.ix.1998; 1 adult, Fururu Forest Reserve (3°24'S: 38°20'E), leaf litter in indigenous forest at 1400 m altitude, leg. C.N. Lange, 26.ix.1998 (NMK). Remarks: Comments made under G. ndiwenyiensis regarding generic placement also apply. Shell shape and dentition immediately suggest an affinity with certain other African Gulella, in particular G. radius (Preston, 1910) of the Shimba Hills and coastal Kenya and Tanzania. The Malawian G. meridithae van Bruggen, 2000, the Comoran G. miniuscula (Morelet, 1877) and the South African–Mozambican G. browni van Bruggen, 1969 share with G. nictitans the biconical shell shape and coarse pattern of apertural dentition and may prove to form a monophyletic group. The Tanzanian G. cuspidata Verdcourt, 1963 might also be referrable to this group, but has more complex dentition than the aforementioned species. Assuming the features shared by all these species are in some way indicative of phylogenetic relatedness, we consider G. nictitans to be a northerly, endemic representative of a group otherwise distributed widely from eastern to south-eastern Africa, and possibly also on Comoros. Certain other land snail groups or taxa, including some streptaxids, have comparable distributions (Herbert & Kilburn 2004; Rowson in press; Verdcourt 2000) but none has yet been reported from the Taita Hills.Published as part of B, Rowson, C, N & Lange, 2007, Two new species of Gulella (Mollusca Pulmonata: Streptaxidae) from the Taita Hills Kenya, pp. 21-32 in African Invertebrates 48 (2) on pages 27-30, DOI: 10.5281/zenodo.766804
Dadagulella ecclesiola Rowson & Tattersfield 2013, sp. nov.
No full textDadagulella ecclesiola sp. nov. urn:lsid:zoobank.org:act: CCE 56537- B 647-4144- AB 07- FE 322 A 139087 Figs 28, 49, 56, 84; Table 1 Etymology From Latin ‘ ecclesiola ’, feminine, diminutive of ‘church’ (or ‘the church’); used arbitrarily to distinguish the species from D. minareta sp. nov. with which it occurs. Type material examined TANZANIA: holotype NMW. Z.2003.001.00015: 1 ad., 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. Paratypes NMW. Z.2003.001.00016: 8 ads, data as holotype. Paratype MRAC. MT.803794: 1 ad., data as holotype. Paratype NHMUK.20120259: 1 ad., data as holotype. Paratype NMK: 1 ad., data as holotype. Paratype NMT: 1 ad., data as holotype. Paratype NMSA. L 8692/ T 3061: 1 ad., data as holotype. Paratype RMNH. MOL.288089: 1 ad., data as holotype. Other material examined TANZANIA: NMW. Z.2003.001.00017: 1 ad., data as holotype, sequenced by Rowson et al. (2010 a) as “ Gulella cf. browni Uluguru ”. NMW. Z.2003.001.00018: 3 ads in poor condition, 3 juvs, data as holotype. Description SHELL (Figs 28, 49, 56). Small to medium-sized (3.20 - 3.70 mm high x 1.80 - 1.90 mm wide), of 5.5 - 7.0 whorls. Ovate-acuminate, spire narrowly accuminate (spire angle 53 - 65°). Apex pointed. Embryonic whorls smoothly granulate. Later whorls with relatively coarse, often sinuous ribs (8 - 14 per mm on penultimate whorl). Sutures deep. Umbilicus closed. Peristome complete. Outer palatal surface of aperture with a depression, often furrow-like, corresponding to the palatal tooth. Dentition 4-fold, consisting of: one strongly oblique parietal tooth, V-shaped when shell turned to the left; one large slablike palatal tooth, forming a narrow, horizontal parieto-palatal sinus; and a deep-set columellar baffle. A basal denticle is also present, presumably in all specimens, but is partly or completely hidden by the palatal tooth which occludes much of the aperture. The denticle is visible when the shell is turned to the right (Fig. 56). Juvenile shells not known with certainty: an individual from Kimboza (Fig. 49), with dentition like that of a juvenile D. r. radius comb. nov., might belong to this species. Anatomy unknown. Range and habitat In forest at the type locality in the eastern Tanzanian lowlands. Remarks This species has much simpler dentition than D. minareta sp. nov. (which also occurs at Kimboza), and is usually smaller, with straight rather than sinuous ribs. Its dentition is more like that of D. r. radius comb. nov. (which again also occurs at Kimboza; Fig. 16) and D. minuscula minuscula (Morelet, 1877) comb. nov. but D. ecclesiola sp. nov. lacks the shallow columellar tooth, has a hidden or partly hidden basal denticle, and has a much narrower parieto-palatal sinus. It further differs from D. minuscula minuscula comb. nov. in having stronger ribs.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 on page 16, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/380677
Dadagulella frontierarum Rowson & Tattersfield 2013, sp. nov.
No full textDadagulella frontierarum sp. nov. urn:lsid:zoobank.org:act: 9D028 B 17-9FCB-47 E 8-96 B 1-5901 B 8 E 3 EA 4 E Figs 34, 61, 84; Table 1 Etymology After Frontier Tanzania, the organisation which collected the specimens; given the ending ‘- arum ’ for a feminine noun in the genitive plural. Type material examined TANZANIA: holotype NMW. Z.2003.074.00001: 1 ad., Mtai Forest Reserve (4.87° S, 38.77° E), East Usambara Mts, Muheza District (plot 69/3), submontane forest at 970 m alt., leg. Frontier Tanzania, 8 Mar. 1997. Paratypes NMW. Z.2003.074.00002: 2 ads, data as holotype. Paratype NMW. Z.2003.074.00003: 1 ad., data as holotype. Paratype NMW. Z.2003.074.00004: 1 ad., data as holotype but 7 Mar. 1997. Paratypes NMT: 2 ads, data as holotype. Other material examined None. Description SHELL (Figs 34, 61). Medium-sized (3.15 - 3.40 mm high x 1.80 - 2.05 mm wide), of 4.5 - 5.0 whorls. Ovateacuminate, spire narrowly acuminate (spire angle 68 - 77°). Apex sharply pointed. Embryonic whorls smoothly granulate. Later whorls with few, widely-spaced, coarse ribs (5 - 7 per mm on penultimate whorl). Sutures very deep. Umbilicus narrowly open. Peristome complete, almost detached. Outer palatal surface of aperture with a depression corresponding to the lower palatal teeth. Dentition 6-fold, consisting of: one complex, V-shaped and flaring parietal tooth; three palatal teeth, the lower two larger and set low down on the palatal surface, not forming a parieto-palatal sinus; one basal, in-running denticle; and one shallow but strong, in-running columellar tooth. Shells and anatomy of juveniles unknown. Range and habitat Submontane forest (970 m elevation) in the East Usambara Mountains, northeastern Tanzania. Remarks The complex dentition and detached peristome of D. frontierarum sp. nov. are unlike that of any other Dadagulella gen. nov. species. It is also characteristic for its few whorls, few ribs and sharply pointed apex. Biogeographically a close relationship with other species in and around the East Usambaras would seem likely but there is no strong resemblance.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 on page 23, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/380677
Pupa menkeana Pfeiffer, 1853, type species of the speciose land snail genus Gulella Pfeiffer, 1856: correction of longstanding PLVLGHQWL¿FDWLRQ DQG GHVLJQDWLRQ RI QHRW\SH (Mollusca: Eupulmonata: Streptaxidae)
No full textHerbert, D. G., Rowson, B. (2011): Pupa menkeana Pfeiffer, 1853, type species of the speciose land snail genus Gulella Pfeiffer, 1856: correction of longstanding PLVLGHQWL¿FDWLRQ DQG GHVLJQDWLRQ RI QHRW\SH (Mollusca: Eupulmonata: Streptaxidae). African Invertebrates 52 (2): 233, DOI: 10.5733/afin.052.0201, URL: http://www.bioone.org/doi/abs/10.5733/afin.052.020
Dadagulella browni subsp. mafiensis Rowson & Tattersfield 2013, subsp. nov.
No full textDadagulella browni mafiensis subsp. nov. Figs 21, 54, 84; Table 1 Etymology From Mafia Island, with the final ‘a’ elided for euphony. Type material examined NHMUK.20110174: 1 ad., Mlula, Mafia I. (approx. 7.87° S, 39.76° E), evergreen coastal thicket on clay loam coral rag, leg. Frontier Tanzania, Oct.- Nov. 1990, labelled “ Gulella radius aggreg.” by B. Verdcourt. Other material examined None. Description SHELL (Figs 21, 54). Small (3.30 mm high x 1.80 mm wide), of 6.0 whorls. Ovate-acuminate, spire broadly acuminate (spire angle 65°). Apex conical. Embryonic whorls smoothly granulate. Later whorls with relatively coarse ribs (12 per mm on penultimate whorl). Sutures relatively shallow. Umbilicus narrowly open. Peristome incomplete parietally. Outer palatal surface of aperture with a depression corresponding to the palatal tooth. Dentition 5-fold, consisting of: one lamella-like parietal tooth and one additional parietal denticle; one slab-like palatal tooth, forming a narrow parieto-palatal sinus; one basal denticle; and a deep-set, folded columellar baffle, but no shallower columellar denticles. Shells and anatomy of juveniles unknown. Range and habitat Evergreen coastal thicket at the type locality. Remarks This taxon is in some respects intermediate between the type specimens of D. r. radius comb. nov. and D. b. browni comb. nov., and thus distinct from either, yet difficult to place. It is larger and not as squat as other D. browni comb. nov. s.l., and lacks the additional basal denticle and shallower columellar dentition. Conversely, it has a parietal denticle not seen in D. radius comb. nov. s.l, is smaller and squatter than most D. radius comb. nov. s.l., and has a longer and narrower parieto-palatal sinus than any D. radius comb. nov. s.l. Mafia Island, from which no other Dadagulella gen. nov. are yet known, lies at almost the same latitude (7.8° S) as the apparent northernmost limit of D. b. browni comb. nov. in mainland Tanzania. Given the morphology of this specimen, its latitude and its isolation as an island population, we treat it as a subspecies of D. browni comb. nov.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 on pages 13-14, DOI: 10.5852/ejt.2013.37, http://zenodo.org/record/380677
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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