New narrow-range endemic land snails from the sky islands of northern South Africa (Gastropoda: Streptaxidae and Urocyclidae)
Author
Herbert, David G.
text
European Journal of Taxonomy
2016
2016-10-12
236
1
29
journal article
21869
10.5852/ejt.2016.236
2dfee902-a7fc-472b-bf1d-27029b3504f3
2118-9773
3847840
B51BF718-79F5-47F5-8740-BA181CE88257
Gulella hadroglossa
sp. nov.
urn:lsid:zoobank.org:act:
B0429B6A-4C92-40BB-B2E7-A707A32ADE96
Fig. 3
Etymology
From
hadros
(Gr.) ‘well-developed, great, strong’, and
glossa
(Gr.) ‘tongue’; referring to the large, tongue-like parietal lamella.
Material examined
Holotype
SOUTH AFRICA
:
Mpumalanga
,
Mariepskop Forest Reserve
,
Picnic Trail
,
24.56847° S
,
30.85920° E
,
1545 m
, northern mist-belt forest, in leaf-litter,
D. Herbert
,
L. Davis
&
M. Cole
, stn 14-27,
4 Dec. 2014
, height 3.0 mm, diameter
1.5 mm
(
NMSA
P0230
/T4084, dry specimen).
Paratypes
SOUTH AFRICA
:
Mpumalanga
, same data as
holotype
(
NMSA
P0417/T4085, five dry specimens;
NHMUK
20160038, one dry specimen;
RMNH
.5004142, one dry specimen); Mariepskop Forest Reserve,
24.55117° S
,
30.89395° E
,
1460 m
, indigenous Afromontane forest, in leaf-litter on forest floor, J.L. Horn,
23 Apr. 2005
(
NMSA
W3500/T4081, four dry specimens); Mariepskop Forest Reserve, Bushpig Trail,
24.56795° S
,
30.86138° E
,
1520 m
, northern mist-belt forest, in leaf-litter, D. Herbert, L. Davis & M. Cole, stn 14-22a,
3 Dec. 2014
(
NMSA
P0263/T4082, one dry specimen); Mariepskop Forest Reserve, east facing slope,
24.57108° S
,
30.86014° E
,
1519 m
, leg. M. Cole,
18 Oct. 2010
(
ELM
D16635/T033, three dry specimens); Mariepskop Forest Reserve, in forest beside road at
1520–1700 m
, leg. M. Cole,
3–4 Dec. 2014
(
ELM
D18019/T034, six dry specimens).
Type locality
SOUTH AFRICA
:
Mpumalanga
, Mariepskop Forest Reserve, Picnic Trail,
24.56847° S
,
30.85920° E
,
1545 m
.
Identification
A small species of
Gulella
with a smooth, glossy, pupiform shell and 3-fold apertural dentition including a very large, oblique, tongue-like parietal lamella projecting far beyond the peristome; a mid-labral plate, the upper edge of which forms a narrow ridge-like tooth that runs obliquely inward and downward; a horizontal in-running tooth at columella base.
Fig. 3.
Gulella hadroglossa
sp. nov.
A–E
. Holotype, height 3.0 mm, diameter 1.5 mm (NMSA P0230/ T4084).
F–G
. Juvenile specimen showing apertural dentition, diameter 1.5 mm (paratype, NMSA P0417/T4085).
Description
SHELL (
Fig. 3
). Small, pupiform; adult height 3.0–
3.1 mm
, diameter
1.45–1.55 mm
; H:D 1.96–2.09, with up to 7.25 whorls. Protoconch diameter ~
0.7 mm
, comprising 1.5–1.75 whorls beyond nucleus, smooth and glossy when fresh; junction with teleoconch indistinct. Teleoconch comprising 5.0–5.5 whorls; whorls weakly convex, lacking a shoulder and suture weakly indented (may appear somewhat channelled in eroded specimens); smooth and glossy, sculptured only by occasional weak growthlines, some specimens with faint traces of subsutural pliculae (not evident in
holotype
); growth-lines stronger and more close-set on apertural tube behind peristome. Aperture ovate, but truncated where peristome interrupted in parietal region; aperture rim flaring and strongly recurved, forming a nearly closed channel behind lip; apertural dentition 3-fold (
Fig. 3
C–D): 1) a very large parietal lamella with a tongue-like anterior element that curves outward and to the right, well beyond plane of aperture and then backward towards outer lip; interval between lamella and outer lip partially filled with an overarching shelf, leaving a U-shaped notch behind lamella; 2) a mid-labral plate running inward from a low thickening of outer lip, its upper margin raised to form a narrow ridge that runs obliquely inward and downward (hidden by parietal lamella in frontal view), basal margin usually ill-defined; 3) a narrow in-running tooth near base of columella; a columella lamella is not evident, though in some specimens a very deep-set vertical ledge may be discerned where apertural tube kinks around to join rounded portion of last whorl. A juvenile specimen of ~2.25 teleoconch whorls possessed 4-fold apertural dentition (
Fig. 3
F–G) comprising: two well-developed, flattened, semi-circular teeth set transversely at left and right of basal lip, that on the right more deep-set; a curved parietal tooth just beyond limit of aperture, behind and to the right of which arises a fourth, more rounded tooth; a second, identical set of teeth visible by transparency one half-whorl behind aperture. Umbilicus closed, base grooved beneath basal columella tooth (
Fig. 3E
). Empty shells translucent greyish-white when fresh; yellow colour of dried body showing through in live-collected material.
LIVING ANIMAL. No preserved specimens available.
Distribution
A narrow-range endemic, currently recorded only from Mariepskop Forest Reserve on the edge of the Drakensberg Escarpment in northern
Mpumalanga
,
South Africa
; at altitudes from
1460 to 1545
m
.
Habitat
Northern mist-belt forest (
Mucina & Rutherford 2006
), in leaf-litter.
Remarks
Gulella hadroglossa
sp. nov.
is rendered distinctive amongst small, smooth-shelled
Gulella
species on account of its large recurved parietal lamella. It is comparable in size (slightly smaller) and superficially similar to
G. verdcourti
Bruggen, 1966
, from the neighbouring Wolkberg massif, but that species has a distinct subsutural shoulder resulting in an incised suture, and its apertural dentition is also different, the parietal lamella not projecting as far and the mid-labral tooth being stronger.
Family
Urocyclidae Simroth, 1889