Page 15 - Chitons_Mollusca_DELL_ANGELO_1998

Chitons in Strait of Sicily

1997 Callochiton calcatus Dell'Angelo and m, grab), 14 plates; st. 284 (Skerki bank, -97
Palazzi - Dell'Angelo an d Giusti, p. 53, Fig. m, grab ), l p late; st. 285 (Skerki bank, -91 m,
7 grab), 11 plates; st. 291 (Skerki bank, -70 m,
grab ), l O plates; st. 292 (Skerki bank, -78 m,
Material: st. 71 (Graham bank, -119 m, grab ), 11 plates; st. 295 (Skerki bank, -l 01
grab ), l p late; st. 88 (Favignana isl., -36 m m, grab), 10 plates; st. 296 (Skerki bank; -38
grab ), 40 plates. m, grab ), 2 spm.; st. 298 (Skerki bank, -64 m,
grab ), 3 plates.
Remarks: Callochiton calcatus is a recen-
tly described species that differs from the ot- Remarks: this Mediterranean Callochiton
her known Mediterranean species (C. sep- has been confused until recent times with C.
temvalvis) principally by its small size (maxi- laevis (Montagu, 1803, not Pennant, 1777)
mum Iength 5 mm), noticeable dorsal eleva- and C. achatinus (Brown, 1823). Kaas (1978)
tion, more raised lateral areas, and uniform has proposed to adopt the name C. septem-
colour patterns. valvis (Montagu, 1803), and to separate sub-
specifically the typical Atlanti c form, viz., C.
Ecology: the species is found at depths septemvalvis septemvalvis, from the Mediter-
between 30 and 100 m, and is probably lin- ranean one, viz., C. septemvalvis euplaeae (0.
ked with coralligenous and maerl habitats. A G. Costa, 1829); the latter is characterized
possible association of C. calcatus with the by a smaller size and by the presence of 3-5
calcareous alga Lithothamnion valens Foslie longitudinal grooves on both sides of the
1909, is suggested by Basso (1995). centrai areas, which may or may not reach
the front margins of the valves. Dell'Angelo
Distribution: this rare taxon is at present and Palazzi (1994) suggested to adopt the
only known for the Mediterranean basin, taxon Callochiton septemvalvis (Montagu,
ranging from the Balearic isles to the Tyrr- 1803) to designate this species in its com-
henian coasts of ltaly and Sicily. plex, also considering that Chiton euplaeae
was clearly described by O. G. Costa (1829)
Callochiton septemvalvis (MONTAGU, 1803), as a species with a smooth surface, without
Pl. 3, Figs. l, 5 any trace of scars. Nearly ali collected plates
show some Iongitudinal grooves on the pleu-
Selected references: ral area.
1803 Chiton septemvalvis Montagu, p. 3
1985 Callochiton euplaeae (O.G.Costa) - Ga- Ecology: C. septemvalvis Iives from the up-
glini, Pl. 9, Fig. 4; Pl. 8, Figs. 5-6; Pl. 9, Figs. per subtidal zone down to a depth of 500 m,
1-2 ( cum syn. ) more frequently on corallinous algae.
1985b Callochiton septemvalvis (Montagu) - Distribution: the species is widely distri-
Kaas an d Va n Belle, p. 11, Fig. 2 ( cum syn.) buted in the Atlantic Ocean from Norway to
1990 Callochiton septemvalvis (Montagu) - the Canary islands, and in the Mediterra-
Mifsud et al., p. 56, Fig. 11 nean.
1993 Callochiton septemvalvis euplaeae (O.G.
Costa) - Giovine and Dell'Angelo, p. 161
1994 Callochiton septemvalvis (Montagu) - Subfamily LEPIDOCHITONINAE Iredale
Dell'Angelo and Palazzi, p. 15, Figs. 13, 20A 1914
Genus Lepidochitona Gray 1821
Ma te riai: st. 37 ( -109 m grab ), 3 plates; st. Subgenus Lepidochitona s.str.
71 (Graham bank, -119m, grab), 4 plates; st.
84 (Favignana isl., Secca del Toro, -62 m, Lepidochitona (L.) furtiva (MONTEROSATO,
grab ), 17 plates; st. 85 (Favignana isl., Secca 1879)
del Toro, -61 m, grab), 3 plates; st. 86 (Favi-
gnana isl., Secca del Toro, -51 m, grab), l Selected references:
p late; st.88 (Favignana isl., -36 m, grab ), 23 1879 Chiton furtivus Monterosato, p. 19
plates; st. 93 (Scuso bank, -113 m, grab ), 11 1981 Lepidochitona (L.) furtiva (Di Monte-
plates; st. 282 (Skerki bank, -113/141 m, rosato) - Kaas and Van Belle, p. 34, Figs.
dredge), 17 plates; st. 283 (Skerki bank, -107 113-127

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