Dadagulella rondoensis ( Verdcourt, 1994 ) 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 : 30-31

publication ID

https://doi.org/ 10.5852/ejt.2013.37

publication LSID

lsid:zoobank.org:pub:ADF6394E-77B5-4309-87FE-4097FDE0A3FD

DOI

https://doi.org/10.5281/zenodo.3815779

persistent identifier

https://treatment.plazi.org/id/4511E41D-D839-FFD8-FE7E-FBF6F6ECFCF7

treatment provided by

Carolina

scientific name

Dadagulella rondoensis ( Verdcourt, 1994 )
status

comb. nov.

Dadagulella rondoensis ( Verdcourt, 1994) View in CoL comb. nov.

Figs 41 View Figs 41-42 , 84 View Fig ; Table 1 View Table 1

Gulella rondoensis Verdcourt, 1994: 137-139 View in CoL , fig. 1.

Gulella rondoensis View in CoL – Verdcourt 2006: 48.

Type material examined

TANZANIA: holotype SMF.310150 : 1 ad., Rondo Forest Reserve, Rondo Plateau, Lindi District (10.12°S, 39.22°E), evergreen forest with Milicia Sim , Albizia Durazz. , Dialium L. , etc. in small gully and amphitheatre around a well on escarpment, 650 m alt., leg. Bidgood, Abdallah & Vollesen , 10 Feb. 1991 (examined digital photograph only). GoogleMaps

Other material examined

None.

Description

SHELL ( Fig. 41 View Figs 41-42 ). Large (4.10 mm high x 2.20 mm wide), of 6.25 whorls. Subconical (maximum width being in bottom third of the shell, at body whorl). Spire narrowly acuminate, almost cyrtoconoid (convex) rather than coeloconoid (spire angle 52°). Apex sharply pointed. Embryonic whorls punctate or malleate, rather than merely granulate. Later whorls with relatively fine ribs (about 14 per mm on penultimate whorl). Sutures of intermediate depth. Umbilicus narrowly open. Peristome incomplete parietally. Dentition weak, 3-fold (although could be interpreted as 2-fold), consisting of: one lamellalike parietal tooth, with a swelling above it that recalls the one in D. conoidea ; one weak palatal tooth, not forming a parieto-palatal sinus; and one very weak, shallow columellar swelling. Further minute swellings just perceptible in the holotype ( Fig. 41 View Figs 41-42 ) were not noted by Verdcourt (1994) who interpreted the dentition as 2-fold. Shells and anatomy of juveniles unknown.

Range and habitat

Forest at the type locality, southeastern Tanzania.

Remarks

This species differs from D. conoidea comb. nov. in its weaker dentition, smaller size, and in having punctate apical whorls. Along with D. conoidea comb. nov. and D. delta sp. nov. it has weaker dentition than other Dadagulella gen. nov. However, both D. rondoensis comb. nov. and D. conoidea comb. nov. are distinctively more conical, i.e. less ovate than other Dadagulella gen. nov. These two are attributed to the genus somewhat speculatively, on the basis of their acuminate spire and pointed apex. These features mean they do not obviously fit into Gulella or any of its named subgenera, or indeed other plausible streptaxid genera. No anatomical or juvenile shell data are available for either species, both being known from single specimens. The punctuate apex of D. rondoensis comb. nov., unique in Dadagulella gen. nov., may not be significant in this respect (see Rowson 2007b for a discussion on the value of apical sculpture in distinguishing African streptaxid genera). The apex of D. conoidea comb. nov. is less obviously punctuate, although it may have been worn smooth ( Verdcourt 1996). In the description of D. rondoensis comb. nov., Verdcourt (1994) discussed a resemblance only to Gulella galactochila (Crosse, 1885) , a much larger and more broadly acuminate Tanzanian species that we consider to lack the characteristic features of Dadagulella gen. nov. Although G. galactochila has not been dissected, the anatomy of another species very similar to it ( G. udzungwensis van Bruggen, 2003 ) lacks the anatomical features of Dadagulella gen. nov. (Rowson unpublished). In his discussion of D. conoidea comb. nov., Verdcourt (1996) made no reference to either D. rondoensis comb. nov. or G. galactochila , but only to two species that we here treat in Dadagulella gen. nov. ( D. r. radius comb. nov. and D. cuspidata comb. nov.). We contend firstly that D. rondoensis comb. nov. and D. conoidea comb. nov. are more similar to one another than either is to G. galactochila , and secondly that the resemblance between D. conoidea comb. nov., D. r. radius comb. nov. and D. cuspidata comb. nov. extends also to D. rondoensis comb. nov.. Our attribution of them to Dadagulella gen. nov. reflects this point of view.

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Stylommatophora

Family

Streptaxidae

Genus

Dadagulella

Loc

Dadagulella rondoensis ( Verdcourt, 1994 )

Rowson, Ben & Tattersfield, Peter 2013
2013
Loc

Gulella rondoensis

Verdcourt B. 2006: 48
2006
Loc

Gulella rondoensis

Verdcourt B. 1994: 139
1994
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