Eight new species of Gulella Pfeiffer, 1856 from the south-east coast of South Africa (Gastropoda: Streptaxidae)
Author
Cole, Mary L.
FDA80F4A-4E08-401E-8FF6-778E033BBBA7
East London Museum, 319 Oxford St, East London, 5201, South Africa and Department of Zoology and Entomology, Rhodes University, Makhanda, 6140, South Africa.
marybursey@elmuseum.za.org
Author
Herbert, David G.
0C09EE45-6198-482E-857A-EF690C2A016F
Department of Natural Sciences, National Museum Wales, Cardiff, United Kingdom and University of KwaZulu-Natal, P. Bag. X 01, Scottsville, 3209, South Africa.
phasianella@gmail.com
text
European Journal of Taxonomy
2022
2022-04-11
813
1
32
http://dx.doi.org/10.5852/ejt.2022.813.1729
journal article
56043
10.5852/ejt.2022.813.1729
ac406bb4-11b2-425e-b793-599560c503d9
2118-9773
6448751
687DE2C9-28A4-43E6-A47D-DE2D2839AB60
Gulella fordycei
sp. nov.
urn:lsid:zoobank.org:act:
8E77FF84-C946-433A-8070-A4CB4036053D
Figs 2
,
3A–D
Diagnosis
SHELL minute, cylindrical; smooth and glossy, but with weak axial riblets below suture; apertural dentition seven-fold, including a sinuous parietal lamella, a large labral complex extending deeply into aperture with ridge-like upper and lower margins and a groove in centre, a low, deeply inset transverse basal tooth to right of centre, a ridge-like basal tooth to left of centre beginning close to lip edge and a large inset tricuspid columella lamella; umbilicus widely open.
Fig. 1.
Gulella kenbrowni
sp. nov.
, holotype (NMSA P1678/T4524), length 2.20 mm, width 0.95 mm.
A
. Aperture view.
B
. Side view.
C
. Oblique view into aperture.
D
. Oblique view of base showing umbilicus. Scale bar = 0.5 mm.
Etymology
Named after the
type
locality, Fort Fordyce.
Material examined
Holotype
SOUTH AFRICA
–
Eastern Cape
•
Fort Fordyce Nature Reserve
,
kloof with watercourse and sheer krantz
;
32.6881°S
,
26.5130°E
;
915 m
a.s.l.
;
31 Mar. 2016
;
M. Cole
leg.;
NMSA
P1679/T4525
, prev. ELMD 18109.
Paratypes
SOUTH AFRICA
–
Eastern Cape
•
4 specs
.;
Fort Fordyce Nature Reserve
,
near Harris Hut
;
32.6834° S
,
26.4767°E
;
1072 m
a.s.l.
;
5 Oct. 2009
;
M. Cole
leg.;
ELMD 16088/T 218
•
2 specs
.;
Fort Fordyce Nature Reserve
,
south-facing slope behind lookout
;
32.6956°S
,
26.4857°E
;
1120 m
a.s.l.
;
3 Jan. 2010
;
M. Cole
leg.;
ELMD 16317/T 219
•
2 specs
.; same collection data as for preceding;
NMSA
P1616/ T4498
, prev. ELMD 16317
•
2 specs
.; same collection data as for preceding;
NMW.Z.2021.011.00002
, prev. ELMD 16317
•
6 specs
.;
Fort Fordyce Nature Reserve
,
kloof with watercourse and sheer krantz
;
32.6881°S
,
26.5130°E
;
915 m
a.s.l.
;
29 Dec. 2008
;
M. Cole
leg.;
ELMD 16377/T 220
•
2 specs
.; same collection data as for preceding;
RMNH.MOL.452585
, prev. ELMD 16377
•
3 specs
.; same collection data as for preceding;
6 Oct. 2009
;
ELMD 16073/T 221
•
1 spec.
; same collection data as for preceding;
NHMUK 20210067
, prev. ELMD 16073
•
3 specs
.; same collection data as for preceding;
17 Jan. 2015
;
ELMD 17842/T 222
•
3 specs
.; same collection data as for preceding;
NMSA
P1615/T4497
, prev. ELMD 17842
•
1 spec.
; same collection data as for preceding;
NHMUK 20210068
, prev. ELMD 17842
•
2 specs
.;
Fort Fordyce Nature Reserve
,
between Harris Hut and dam
;
32.6825°S
,
26.4794° E
;
1117 m
a.s.l.
;
18 Jan. 2015
;
M. Cole
leg.;
ELMD 17864/T 223
.
Fig. 2.
Distribution map of
Gulella kenbrowni
sp. nov.
(pink circles),
G. fordycei
sp. nov.
(blue squares),
G. mkombeni
sp. nov.
(green triangles) and
G. crookesi
sp. nov.
(orange square). Contour at 1000 m.
Other material
SOUTH AFRICA
–
Eastern Cape
•
2 specs
.;
Fort Fordyce Nature Reserve
,
kloof with watercourse
,
east-facing
;
32.6704°S
,
26.4851°E
;
1137 m
a.s.l.
;
29 Dec. 2008
;
M. Cole
leg.;
ELMD 16083
•
2 specs
.;
Fort Ford yce Nature Reserve
,
south-facing slope behind lookout
;
32.6956° S
,
26.4857°E
;
1120 m
a.s.l.
;
30 Dec. 2008
;
M. Cole
leg.;
ELMD 16085
.
Description
SHELL (
Fig. 3
). Shell minute, cylindrical, length
2.2–2.5mm
, width 1.0–
1.1 mm
, L:W 2.1–2.3 (n = 6). Protoconch approx.
1mm
in diameter, comprising approx. 2.25 whorls, smooth and glossy; junction between protoconch and teleoconch evident. Teleoconch comprising approx. 3.5–4 whorls; first whorl convex, remaining ones weakly so; weak axial riblets extend more or less half-way down each whorl, stronger immediately below sutures (
Fig. 3B
). Aperture sub-quadrate, rounded basally, markedly constricted by teeth; peristome thick and reflected, broadly interrupted in parietal region; dentition eightfold (
Fig. 3C
): 1) a strong parietal lamella with inner portion which runs into aperture somewhat sinuous, outer portion curving to right; parietal lamella projects well beyond profile of aperture in side view; 2) a large labral slab extending into aperture beyond columella lamella (in apertural view), with ridges on its upper and lower margins, bordering a V-shaped central groove, upper ridge sharp with a cusp near lip edge in close proximity to parietal lamella; 3) a low, deeply inset transverse basal tooth to right of centre; 4) an in-running basal ridge to left of centre beginning near lip edge; 5–7) a large columella lamella with three teeth, upper two ridge-like and lowest one small, sometimes little more than a low bulge, middle one largest and extending closer to lip edge. Labral slab corresponds with a deep pit behind outer lip (
Fig. 3B
); basal ridge with a shallow indentation behind lip. Umbilicus widely open, elongate-oval, with a deep indentation underlying columella lamella, indistinct axial pleats around umbilicus (
Fig. 3D
). Shell almost transparent when fresh, orange-red coloration of dried tissue of animal visible internally.
Distribution
(
Fig. 2
)
Endemic to the Fort Fordyce Nature Reserve, considered part of the Amathole Mountains; at altitudes between
900m
and
1150 m
above sea level.
Habitat
Amathole Mistbelt Forest (Southern Mistbelt Forest group) (
von Maltitz
et al
. 2003
); in leaf-litter and under logs.
Remarks
Gulella fordycei
sp. nov.
is very similar to
G. kenbrowni
sp. nov.
except that it has weak subsutural riblets and is larger (mean length
2.3mm
and
2.1mm
, respectively). The parietal lamella does not run parallel to the upper ridge of the labral slab, but the lowest point of its edge is in close proximity to the labral slab in the vicinity of the cusp. The labral complex is slightly differently shaped; the ridges of the labral slab have a V-shaped groove between them in
G. fordycei
sp. nov.
The basal ridge to left of centre commences close to the lip edge and causes a shallow external furrow behind the lip, absent in
G. kenbrowni
sp. nov.
In addition, the ridge-like middle tooth of the columella lamella is closer to the columella lip. Compared to other species described herein, the protoconch of
G. fordycei
sp. nov.
is large relative to the size of its shell.
The labral slabs of
Gulella fordycei
sp. nov.
and
G. kenbrowni
sp. nov.
closely resemble those of
G. bomvana
and
G. tietzae
from the
Eastern Cape
coast and several narrow-range species endemic to Zululand,
G. genialis
(Melvill & Ponsonby, 1903)
,
G. laevorsa
Burnup, 1925
and
G. vallaris
(Melvill & Ponsonby, 1907)
(see
Gulella
Group
9 in
Herbert & Kilburn 2004
). These Zululand species, however, all possess strong axial riblets running from suture to suture. The tricuspid columella lamella of
G. fordycei
sp. nov.
and
G. kenbrowni
sp. nov.
closely resembles that of
G. bomvana
and several other smooth-shelled
Gulella
species
from the
Eastern Cape
coast with a tricuspid columella,
Gulella aprosdoketa
Connolly, 1939
,
G. tietzae
and
G. ndibo
Cole & Herbert, 2009
, but in the latter three species the columella lamella extends to the lip edge.
Fig. 3
.
Gulella fordycei
sp. nov.
, holotype (NMSA P1679/T4525), length 2.34 mm, width 1.06 mm.
A
. Aperture view.
B
. Side view.
C
. Oblique view into aperture.
D
. Oblique view of base showing umbilicus. Scale bar = 0.5 mm.
Conservation
Gulella fordycei
sp. nov.
has been found only at Fort Fordyce Nature Reserve, an outlier of the Amathole Mountains, despite extensive collecting efforts throughout the region. It therefore appears to be a very narrow-range endemic. Fort Fordyce is a protected area under the jurisdiction of the
Eastern Cape
Parks and Tourism Agency. It is known for endemicity of other terrestrial molluscs, viz.
Amatholedonta fordycei
Herbert, 2020
(Charopidae)
and an undescribed species of
Fauxulus
(
Anisoloma
) (Fauxulidae)
. Furthermore, specimens of another litter-dwelling invertebrate, the velvet worm
Peripatopsis sedgwicki
(Purcell, 1899)
from Fort Fordyce were genetically and morphologically distinct, suggesting the presence of a novel lineage at Fort Fordyce (
Daniels
et al
. 2017
).