On the relationships of the genus Napaeus (Gastropoda: Pulmonata: Enidae) with the descriptions of four new species from the Canary Islands
Author
Yanes, Yurena
Author
Martín, Javier
Author
Moro, Leopoldo
Author
Alonso, María R.
Author
Ibáñez, Miguel
text
Journal of Natural History
2009
2009-08-26
43
35 - 36
2179
2207
http://dx.doi.org/10.1080/00222930903094621
journal article
10.1080/00222930903094621
1464-5262
5217087
Napaeus ornamentatus
Moro
sp. nov.
Type material
Holotype
(
Figures 4F
,
7C
): TFMC (
MT 0400
). Type locality:
Mirador
de Taguluche
(
La Gomera
;
UTM
coordinates: 28
RBS7113
;
800 m
altitude). Leg. Javier Martín and Leopoldo Moro,
5 March 2008
.
Paratypes
:
15 specimens
and 26 shells, collected between 1981 and 2009, from
western La Gomera
(
UTM
coordinates: 28
RBS7011
,
28
RBS7016, 28RBS7113, 28RBS7115, 28RBS7116, 28RBS7212, 28RBS7214, 28RBS7319, 28RBS7405, 28
RBS7508
and 28
RBS7609
), deposited in TFMC (
MT 0136
/1),
CML
(six shells) and AIT
.
Etymology
The specific name derives from the distinctive shell ornamentation.
Geographic range and habitat
Ground dweller endemic to La Gomera, with a distribution area of about
60 km
2 on
the western side of the island, mainly related to lowland vegetation and semi-arid subtropical scrub and palm grove, ranging in altitude from
175 to 1000 m
(
Figure 1B
).
Diagnosis
Shell elongated ovate–cylindrical, cone-shaped above. Protoconch very fragile. Teleoconch heavily ornamented with strong, laminar, prominent and irregularly undulating radial oblique ribs. Shell colour tan brown, with first whorls slightly darker than the rest. Epiphallus without epiphallar caecum. Bursa copulatrix duct without diverticulum.
Description
Shell (
Figures 7C, E
) obese (SB/SH index), elongated ovate–cylindrical, cone-shaped above, 7–7½ convex whorls, deeply marked suture. Body whorl intermediate (BH/SH index), protoconch smooth, shiny, with 1½–1¾ whorls. Protoconch very fragile, broken in many shells and living specimens. Aperture short, wide (AH/SH and AB/SB indices, respectively), with elliptical section at palatal side, rounded at union of columellar and palatal edges. Upper palatal side forms angle slightly less than 90º with parietal side, aperture juts out only slightly from body whorl beginning. Whitish discontinuous peristome expanded as lip, more developed in lower part of palatal edge, reflected in columellar edge, where it partially covers umbilical slit. Older specimens with callosity between peristome edges, nodule at union of parietal–palatal area.
Shell colour dark brown, first teleoconch whorls slightly darker than rest. Heavily ornamented teleoconch characterized by strong, laminar, prominent, irregularly undulating, sometimes interrupted radial oblique ribs (
Figures 7C, E
,
10D
). Ribs of body whorl more regularly located.
Genital system (
Figure 11B
;
five specimens
dissected). Atrium very short. Penis mainly tubular, slightly longer than A
1
portion of penial appendix. Penis with three portions, distal portion located between atrium and insertion of the penial retractor muscle; proximal portion small, slightly widened, with incipient penial papilla; intermediate portion slender, tubular, slightly longer than distal portion. Epiphallus long, tubular, without epiphallar caecum, opening distally on penis. Flagellum short. Vas deferens opens laterally on proximal end of epiphallus. Penial appendix arises near distal end of penis, is longer than penis and epiphallus together. A
1
penial appendix portion similar in length to penis. Appendicular retractor muscle inserted laterally, at certain distance of proximal top of A
1
portion; insertion on diaphragm walls very close, but not fused to penial retractor. Free oviduct slightly longer than vagina. Bursa copulatrix complex without diverticulum.
Remarks
Shell morphology.
Within the conchological group of
N. variatus
, the shell of
N. ornamentatus
sp. nov.
(
Figure 4F
) is quite similar in form and size to that of
N. propinquus
(
Figure 4E
), and also comparable with that of
N. maffioteanus
(
Figure 5A
), although the latter species is more cylindrical. The first whorls of
N. ornamentatus
and
N. propinquus
are smaller than those of
N. maffioteanus
(
Figure 6G
). The body whorl and the aperture of
N. ornamentatus
and
N. maffioteanus
are similar in form and size but smaller than those of
N. propinquus
(
Figure 6H
). The main difference between
N. ornamentatus
and the other two species is in the shell ornamentation, which is smooth and not strongly developed in
N. maffioteanus
and
N. propinquus
(
Figures 12E and 12F
, respectively), in contrast to that of
N. ornamentatus
(
Figure 10D
). Besides,
N. ornamentatus
has a high protoconch.
Genital system anatomy.
The genital systems of
N. ornamentatus
and
N. propinquus
are similar in shape and dimensions but
N. propinquus
has an epiphallar caecum that is absent in
N. ornamentatus
.
The genital system of
N. maffioteanus
has an epiphallar caecum and also a well-developed diverticulum in the bursa copulatrix complex, whereas
N. ornamentatus
lacks both structures.