Page 10 - Chitons_Mollusca_DELL_ANGELO_1998

B. Dell'Angelo, C. Lombardi and M. Taviani

Selected references: 1989 Lepidopleurus (Parachiton) africanus
1985a Leptochiton (L.) geronensis Kaas and Nierstrasz - Dell'Angelo and Palazzi, p. 80,
Van Belle, p. 67, Fig. 28 Pls. 23-24 ( cum .syn.)
1985 Leptochiton geronensis Kaas and Van 1990 Leptochiton (Parachiton) africanus
Belle - Della Bella and Dell'Angelo, p.309, (Nierstrasz) - Bedulli, Dell'Angelo and Pa-
Fig. l netta, p. 31
1990 Leptochiton geronensis (Kaas and Van 1990 Leptochiton africanus Nierstrasz - Mif-
Belle) - Mifsud et al., p. 54, Fig. 2 sud et al., p. 54, Fig. 12

Materia!: st. 30 ( -217 m, grab ), l spm. Materia!: st. 22 ( -62 m, rock dredge ), l
spm. (length 8 mm); st. 50 (Terribile bank,
Remarks: we bave found one single, small -110 m, grab), l plate; st. 93 (Scuso bank,
living individuai of this rare polyplacopho- -113 m, grab ), 18 plates; st. 254 (Pantelleria
ran. This species has been established from isl., -44 m, grab), l spm. (length 23.5 mm);
two specimens collected by fishermens off st. 282 (Skerki bank, -113/141 m, dredge), 5
Gerona (Spain) between 200-250 m. plates; st. 283 (Skerki bank, -107m, grab): 2
plates; st. 285 (Skerki bank, -91 m, grab ), l
Ecology: L. geronensis is a deep-water spe- p late; st. 291 (Skerki bank, -70 m, grab ), l
cies distributed below 100 m of depth and p late; st. 292 (Skerki bank, -78 m, grab ), 3
found in association with ahermatypic corals plates; st. 295 (Skerki bank, -101 m, grab), 2
(Spain) and coralligenous habitats (Tuscan plates.
archipel).
Remarks: L. africanus is a rare species,
Distribution: so far reported only from originally described from a single specimen
the Mediterranean basin, viz. Gerona, For- found in Algerian waters. No other records
miche di Grosseto (Tuscan archipel), and bave been reported for about 70 years unti!
Malta. a second specimen was found at Gallipoli
(Apulia), followed by sporadic findings in
the Tyrrhenian and lonian seas (Bedulli et
Subgenus Parachiton Thiele 1909 al., 1990). We bave found two living indivi-
duals plus a number of loose plates, the lat-
Lepidopleurus (Parachiton) africanus Nier- ter mostly within the biogenic fraction of the
strasz 1906, P l. l, Figs. 2-4, 6-7 coarse sediment carpeting the Skerki bank
below 70 m. The living specimen dredged off
Selected references: Pantelleria isl. is exceptional since attaining
1906 Lepidopleurus africanus Nierstrasz, the largest known size for this taxon which
p.l55, Pl. 3, Figs. 1-9 normally averages 7-10 mm of length, and
1981 Lepidopleurus (Parachiton) africanus because it shows an unusual purplish, red-
Nierstrasz - Laghi, Russo and Dell'Angelo, spotted colour.
p. l, Pl. l, Figs. 3-9
1985a Leptochiton (Parachiton) africanus Ecology: this taxon seems typically asso-
(Nierstrasz) - Kaas and Van Belle, p. 163, ciated to rhodalgal biogenic sediments, bet-
Fig. 75 ween 25-150 m. Our records confirm this in-
1987 Leptochiton (Parachiton) africanus terpretation since our two individuals bave
(Nierstrasz) - Cesari, p. 12, P!. 9, Figs. 1-6; been found attached on a dead shell of Pec-
P!. 10, Figs.l-5 tenjacobaeus and on a living rhodolith. Furt-

Pl. 2 - l, Hanleya hanleyi (CS96-84), intermediate valve, width 2.5 mm; 2, Hanleya hanleyi (CS96-93), valve VIII,
width 1.5 mm; 3, Lepidopleurns cimicoides (CS96-71), valve VIII, width 1.5 mm; 4, Lepidopleurns cimicoides (CS96-
71), valve VIII, detail of sculpture (230 x); 5, Callochiton calcatus (CS96-88), intermediate valve, width 1.5 mm; 6,
lschnochiton vanbellei (CS96-283), intermediate valve, width 3 mm; 7, Callochiton calcatus (CS96-88), intermediate
valve, anterior view, width 1.5 mm; 8, lschnochiton vanbellei (CS96-283), valve VIII, width 3 mm.