Post by surroundx on Nov 10, 2012 7:02:06 GMT
Pachnodus (Nesiocerastus) ladiguensis sp. nov. (Fig. 5a)
Pachnodus sp. Griffiths & Gerlach 1991; 7
Pachnodus ‘La Digue’ Gerlach 1997: 45, 1999: 252
Type material: Holotype (AMS C426122), 1 paratype (AMS C426123) - in sandy trenches,
just N of Flycatcher Reserve, Anse La Reunion, La Digue; iv.2001, O.L. Griffiths; 1 paratype
(NPTS M1999.3) – iii.1992; J. Gerlach. Additional non-type sepecimens in NTS and O.
Griffiths collections, same locality as types.
Etymology: Named after the island of origin, La Digue.
Description: Shell: Shell conical with 6-6.25 whorls and 1 nuclear whorl, strong; surface
shiny; irregular radial ridges, no spiral striae detectable. Suture with a slight ridge. Apex
blunt; umbilicus open (1-1.8mm wide), partially covered by the columella; mouth edge
slightly reflexed but not forming a true lip. Coloration originally mahogany brown with
a dark spiral band on the middle of the body whorl and a pink tint to the columella. Most
specimens are bleached and it is not known if the spiral band and the pink columella were
normal characters.
Body and anatomy: Unknown.
Distribution: La Digue, Seychelles; only sub-fossil material from the plateau at La Reunion.
Notes: This species is most similar to P. praslinus and P. fregatensis but is distinguished by
the presence of a slight sutural ridge. P. praslinus has a broader aperture. The material consists of subfossil shells and fragments. No traces of recent shells or live specimens have been found on La Digue despite repeated searching, the species is therefore believed to be extinct. The subfossils were collected from spoil heaps and from ditches dug on the plateau. They were found in association with Subulina octona, Paropeas achatinaceum, Caeciloides mauritiana, Stylodonta unidentata and Tropidophora pulchra. Specimens found in situ were 15cm below the surface. The widespread alien species Achatina fulica was restricted to the top 10cm of soil. This species was introduced to Seychelles
in the early 1800s (Dufo 1840), indicating that P. ladiguensis became extinct shortly after the island was colonized in the late 18th to early 19th century. The abundance of shells of species now rare on La Digue (T. pulchra and S. unidentata) in these deposits suggests that these species have declined due to human disturbance, probably forest clearance.
Source: www.islandbiodiversity.com/Phelsuma%2011-4.pdf
Pachnodus sp. Griffiths & Gerlach 1991; 7
Pachnodus ‘La Digue’ Gerlach 1997: 45, 1999: 252
Type material: Holotype (AMS C426122), 1 paratype (AMS C426123) - in sandy trenches,
just N of Flycatcher Reserve, Anse La Reunion, La Digue; iv.2001, O.L. Griffiths; 1 paratype
(NPTS M1999.3) – iii.1992; J. Gerlach. Additional non-type sepecimens in NTS and O.
Griffiths collections, same locality as types.
Etymology: Named after the island of origin, La Digue.
Description: Shell: Shell conical with 6-6.25 whorls and 1 nuclear whorl, strong; surface
shiny; irregular radial ridges, no spiral striae detectable. Suture with a slight ridge. Apex
blunt; umbilicus open (1-1.8mm wide), partially covered by the columella; mouth edge
slightly reflexed but not forming a true lip. Coloration originally mahogany brown with
a dark spiral band on the middle of the body whorl and a pink tint to the columella. Most
specimens are bleached and it is not known if the spiral band and the pink columella were
normal characters.
Body and anatomy: Unknown.
Distribution: La Digue, Seychelles; only sub-fossil material from the plateau at La Reunion.
Notes: This species is most similar to P. praslinus and P. fregatensis but is distinguished by
the presence of a slight sutural ridge. P. praslinus has a broader aperture. The material consists of subfossil shells and fragments. No traces of recent shells or live specimens have been found on La Digue despite repeated searching, the species is therefore believed to be extinct. The subfossils were collected from spoil heaps and from ditches dug on the plateau. They were found in association with Subulina octona, Paropeas achatinaceum, Caeciloides mauritiana, Stylodonta unidentata and Tropidophora pulchra. Specimens found in situ were 15cm below the surface. The widespread alien species Achatina fulica was restricted to the top 10cm of soil. This species was introduced to Seychelles
in the early 1800s (Dufo 1840), indicating that P. ladiguensis became extinct shortly after the island was colonized in the late 18th to early 19th century. The abundance of shells of species now rare on La Digue (T. pulchra and S. unidentata) in these deposits suggests that these species have declined due to human disturbance, probably forest clearance.
Source: www.islandbiodiversity.com/Phelsuma%2011-4.pdf