Dadagulella conoidea ( Verdcourt, 1996 ) 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 : 32-34

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.3815777
persistent identifier	https://treatment.plazi.org/id/4511E41D-D83B-FFE6-FE7B-FCBAF724F80C
treatment provided by	Carolina
scientific name	Dadagulella conoidea ( Verdcourt, 1996 )
status	comb. nov.

Treatment

Dadagulella conoidea ( Verdcourt, 1996) View in CoL comb. nov.

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

Gulella conoidea Verdcourt, 1996: 135-137 View in CoL , fig. 1.

Gulella conoidea View in CoL – Tattersfield 1998b: 37. — Verdcourt 2006: 48.

Type material examined

TANZANIA: Holotype RMNH.MOL.57150 : 1 ad., East Usambara foothills, Kwamgumi/Segoma Reserve , about 4.57°- 4.58°S, 38.43° - 38.45°E, near Muzi R./Sigi R. junction, leg. Frontier Tanzania (examined digital photograph only). GoogleMaps

Other material examined

None.

Description

SHELL ( Fig. 42 View Figs 41-42 ). Large (5.5 mm high x 2.80 mm wide), of 8.0 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 48°). Apex sharply pointed. Embryonic whorls “probably smooth but worn” ( Verdcourt 1996). Later whorls with relatively weak ribs (about 11 per mm on penultimate whorl). Sutures relatively shallow. Umbilicus narrowly open. Peristome incomplete parietally, or nearly so. Dentition 3-fold (although could be interpreted as 4-fold), consisting of: one lamella-like parietal tooth, with a swelling above it that recalls that in D. rondoensis comb. nov.; one strongly bifid palatal tooth (or pair of teeth), not forming a parieto-palatal sinus; and a shallow columellar tooth or denticle. Shells and anatomy of juveniles unknown.

Range and habitat

Altitude and habitat not stated but probably in lowland forest at approximately 200 m at the type locality, northeastern Tanzania. Another species ( D. radius comb. nov.) also occurs at Kwamgumi.

Remarks

See D. rondoensis comb. nov. above.

Key to species and subspecies (adult shells)

1. Dentition simple, 2-fold to 4-fold ( Figs 35 View Figs 27-35 , 38 View Figs 36-40 , 41, 42 View Figs 41-42 , 51, 56, 62 View Figs 51-64 ), never including a parietal denticle to the left of parietal tooth ............................................................................................................... 2

– Dentition complex, 5-fold to 8-fold ( Figs 52-55, 57-61, 63, 64 View Figs 51-64 ) (if in doubt key from here) ......... 8

2. Basal denticle absent ........................................................................................................................ 3

– Basal denticle present (may be partly or wholly hidden behind palatal tooth, e.g. Fig. 56 View Figs 51-64 , so if alternative fails return here) ............................................................................................................. 6

3. Shell small (up to 3.1 mm high) with very fine, very numerous ribs (about 27 per mm on penultimate whorl) ( Fig. 37 View Figs 36-40 ) ...................................................... D. meredithae (van Bruggen, 2000) View in CoL comb. nov.

– Shell large (4.1 - 5.5 mm high) and with 13 or fewer ribs per mm on penultimate whorl ( Figs 35 View Figs 27-35 , 41- 42 View Figs 41-42 ) .................................................................................................................................................... 4

4. Shell ovate-acuminate (maximum width approximately at middle of shell); spire broadly acuminate (spire angle 56° or more); ribs sinuous ( Fig. 35 View Figs 27-35 ) ..................................................... D. delta View in CoL sp. nov.

– Shell subconical (maximum width in bottom third of shell); spire narrowly acuminate (spire angle 52° or less); ribs not sinuous ( Figs 41-42 View Figs 41-42 ) ....................................................................................... 5

5. One palatal tooth, columellar dentition weak or absent; 4.10 mm high ( Fig. 41 View Figs 41-42 ) .............................. ...................................................................................... D. rondoensis ( Verdcourt, 1994) View in CoL comb. nov.

– Two palatal teeth; one strong shallow columellar tooth; 5.5 mm high ( Fig. 42 View Figs 41-42 ) ................................ ......................................................................................... D. conoidea ( Verdcourt, 1996) View in CoL comb. nov.

6. Deep-set columellar baffle clearly visible through aperture (if not so clearly visible, then apex pointed and not rounded) (e.g. Figs 51-57, 62-64 View Figs 51-64 ) .......................................................................... 7

– Columellar baffle barely visible through aperture; apex rounded (Taita Hills, Kenya) ( Fig. 33 View Figs 27-35 ) ...... ............................................................................. D. nictitans ( Rowson & Lange, 2007) View in CoL comb. nov.

7. No columellar dentition other than deep-set baffle; basal denticle present, either completely hidden by a slab-like palatal tooth or visible only when shell is turned (Kimboza, Uluguru Mts, Tanzania) ( Figs 28 View Figs 27-35 , 56 View Figs 51-64 ) ..................................................................................................... D. ecclesiola View in CoL sp. nov.

– Usually with shallow columellar dentition as well as deep-set baffle; basal denticle clearly visible in normal apertural view .................................................................................................................... 19

8. Parietal tooth strongly V-shaped, flaring, directed outwards; three palatal teeth; shell of 5.0 or fewer whorls ( Figs 34 View Figs 27-35 , 61 View Figs 51-64 ) .................................................................................... D. frontierarum View in CoL sp. nov.

– Shell without this combination of characters ................................................................................... 9

9. Upper shallow columellar tooth strong, squarish, projecting into aperture as far or further than any deeper columellar baffle ( Figs 30-31 View Figs 27-35 , 36 View Figs 36-40 , 58-59 View Figs 51-64 ) .......................................................................... 10

– Shallow columellar dentition projecting less far into aperture than any deeper columellar baffle ( Figs 51-57, 60-64 View Figs 51-64 ) ................................................................................................................................. 12

10. Apex rounded; spire broadly acuminate, spire angle 70°; ribs weak, almost disappearing in the middle of the whorl (Virunga NP, DR Congo) ( Fig. 36 View Figs 36-40 ) .................................................................... .............................................................. D. selene (van Bruggen & Van Goethem, 1999) View in CoL comb. nov.

– Apex sharply pointed; spire acuminate or coeloconoid, spire angle 65° or less; ribs prominent, running from suture to suture; apex finely radially striate in fresh specimens ( Figs 30-31 View Figs 27-35 ) .......... 11

11. Shell more than 4.0 mm high; parietal tooth simple, lamella-like; two palatal teeth (W. Usambara Mts, Tanzania) ( Figs 31 View Figs 27-35 , 59 View Figs 51-64 ) .......................................... D. cuspidata ( Verdcourt, 1962) View in CoL comb. nov.

– Shell up to 4.0 mm high; parietal tooth V-shaped; one palatal tooth (elsewhere in Tanzania) ( Figs 30 View Figs 27-35 , 58 View Figs 51-64 ) ..................................................................................................................... D. minareta View in CoL sp. nov.

12. Outer palatal surface of aperture with very deep, long, furrow-like depression; basal denticle absent or not visible in apertural view ( Figs 29, 33 View Figs 27-35 , 57 View Figs 51-64 ) ........................................................................... 13

– Outer palatal surface of aperture with shallow, not furrow-like depression; basal denticle clearly visible in apertural view ................................................................................................................. 14

13. Apex sharply pointed; spire coeloconoid (Ngorongoro, Tanzania) ( Figs 29 View Figs 27-35 , 57 View Figs 51-64 ) .. D. cresswelli View in CoL sp. nov.

– Apex rounded (Taita Hills, Kenya) ( Fig. 33 View Figs 27-35 ) ...... D. nictitans ( Rowson & Lange, 2007) View in CoL comb. nov.

14. Sculpture of widely-spaced, flaring, subtriangular, lamella-like ribs; spire narrowly acuminate (spire angle <50°) (Cabo Delgado, Mozambique) ( Fig. 27 View Figs 27-35 ) ......... D. delgada ( Muratov, 2010) View in CoL comb. nov.

– Shell without this combination of characters ................................................................................. 15

15. Shell 4.8 mm - 5.5 mm high (Pemba I., Tanzania) ( Figs 32 View Figs 27-35 , 60 View Figs 51-64 ) ..................... D. pembensis View in CoL sp. nov.

– Shell up to 4.6 mm high ................................................................................................................. 16

16. Shell up to 3.3 mm high; parieto-palatal sinus narrow, appearing parallel-sided in apertural view; nearly always with an additional, small parietal denticle to the left of parietal lamella; nearly always with two basal denticles ( Figs 21-26 View Figs 6-26 , 54-55 View Figs 51-64 ) ... 17 ( D. browni (van Bruggen, 1969) View in CoL comb. nov. s.l.)

– Shell up to 4.6 mm high; parieto-palatal sinus wide, not parallel-sided in apertural view; always without a small parietal denticle to the left of parietal lamella, even if shell less than 3.3 mm high .............. 19

17. Only one basal denticle present; no columellar dentition other than a deep-set baffle (Mafia I., Tanzania) ( Figs 21 View Figs 6-26 , 54 View Figs 51-64 ) ................................................................... D. browni mafiensis subsp. nov.

– Two basal denticles almost always present; one or two columellar denticles present in addition to a deep-set baffle ( Figs 22-26 View Figs 6-26 , 55 View Figs 51-64 ) ..................................................................................................... 18

18. Shell 3.15 - 3.25 mm high; sutures relatively shallow; peristome complete; parieto-palatal sinus longer and narrower, not widening appreciably towards its inner end (Semuliki NP, Uganda) ( Figs 22 View Figs 6-26 , 55 View Figs 51-64 ; compare with Figs 23-26 View Figs 6-26 ) ............................................ D. browni semulikiensis subsp. nov.

– Shell (2.55 - 3.20 mm high; sutures relatively deep; peristome incomplete parietally; parieto-palatal sinus shorter and broader, widening towards its inner end ( South Africa, Mozambique, S. Tanzania) ( Figs 23-26 View Figs 6-26 ; compare with Figs 22 View Figs 6-26 , 55 View Figs 51-64 ) ............ D. browni browni (van Bruggen, 1969) View in CoL comb. nov.

19. Sculpture of numerous, fine ribs (15 or more per mm on penultimate whorl); spire coeloconoid, elongate ( Mayotte) ( Figs 40 View Figs 36-40 , 64 View Figs 51-64 ) ............................................ D. minuscula mahorana View in CoL subsp. nov.

– Shell without this combination of characters (e.g. Figs 1-20 View Figs 1-5 View Figs 6-26 , 38-39 View Figs 36-40 ) ............................................ 20

20. Shell 4.0 mm or more high, sculpture of few, coarse, widely-spaced ribs (5 - 10 per mm on penultimate whorl); dentition 4-fold to 5-fold (Taru Desert and elsewhere in SE Kenya) ( Figs 6-8 View Figs 6-26 , 51 View Figs 51-64 ). ............ ......................................................................... D. radius View in CoL calva ( Connolly, 1922) View in CoL comb. et stat. nov.

– Shell without this combination of characters ................................................................................. 21

21. Dentition 5-fold or more, although when shallow columellar dentition is weak, might be considered 4-fold (lowlands of SE. Kenya and NE. Tanzania) ( Figs 1-5 View Figs 1-5 , 9-20 View Figs 6-26 , 52-53 View Figs 51-64 ) ....................................... ..................................................................................... D. radius radius ( Preston, 1910) View in CoL comb. nov.

– Dentition 4-fold, lacking a shallow columellar tooth (as in the lectotype) or 5-fold, with a shallow columellar tooth (as in the paralectotype) (Nzwani [Anjouan] I., Comoros) ( Figs 38-39 View Figs 36-40 , 62-63 View Figs 51-64 ) ..... ....................................................................... D. minuscula minuscula ( Morelet, 1877) View in CoL comb. nov.