Opisthobranchs from the western Indian Ocean, with descriptions of two new species and ten new records (Mollusca, Gastropoda)
Author
Yonow, Nathalie
text
ZooKeys
2012
197
1
130
http://dx.doi.org/10.3897/zookeys.197.1728
journal article
http://dx.doi.org/10.3897/zookeys.197.1728
1313-2970-197-1
Phyllidia alyta Yonow, 1996
Fig. 17Plate 61
Phyllidia alyta
Yonow, 1996: 500, fig. 9A-G, tab. 2 (Maldives, Mauritius);
Apte 2009
: 171, fig. 2t (Laccadive Islands);
Yogesh Kumar et al. 2011
: 111, fig. 3a (India).
Phyllidia elegans
. - Eliot 1906: 562 (Maldives) (non
Phyllidia elegans
Bergh).
Material.
Maldives: 25 mm in length, Dhigu Tila, near Gulhi, South
Male
Atoll, 12 m depth, 14 October 1994, leg. SG Buttress & RC Anderson; 28
x
12 mm, Bathala Island, Ari Atoll, 6 m depth, 28 July 1995, leg. SG Buttress & RC Anderson; 15
x
7 mm pres. ("light grey with black lines, rhinophores and last tubercle yellow"), Bathala Island, Ari Atoll, 10 m depth, 27 July 1995, leg. SG Buttress & RC Anderson; photographs of many individuals, 25-40 mm, March 1997, March 1998, March 1999, J Hinterkircher. - Sri Lanka: photos of two individuals, Negombo, N of Colombo, April 1995, RC Anderson; photos of one individual, Unawatuna, S of Galle, 27 December 2010, S Kahlbrock.
Description
.
The preserved 15 mm juvenile is in perfect condition and easily recognised as
Phyllidia alyta
. Broken black line present on sole of foot despite its small size (Fig. 17A), but only two of the four longitudinal dorsal black lines are complete (Plate 61). Three rows of tubercles on midline between start of two lines: central row of tubercles joined by low ridge and only the last tubercle orange. Black crossbar between rhinophores lacking. Two larger specimens typical, with four dorsal black lines, black bar between rhinophores, and ventral broken black line. Foot thickened and concave anteriorly, and triangular tentacles bear groove along each outer side (Fig. 17B). Hyponotum hatched with spicules, dorsal black pigment showing through.
Figure 17.
Phyllidia alyta
, 15 mm pres. specimen A ventral view showing line on sole of foot B view of propodium, head, and oral tentacles.
Distribution.
It is probable that the species described by Eliot (1906) is
Phyllidia alyta
: he distinguishes it from
Phyllidia varicosa
(he had specimens of both), and
Phyllidia alyta
is the only other species in the Indian Ocean with linearly-arranged orange tubercles and black lines dorsally in combination with a black line on the sole of the foot. This species appears to be restricted to the western Indian Ocean; there are only two internet records from south western Thailand on NudiPixel.