Stenothoe cattai Stebbing, 1906

Krapp-Schickel, Traudl, 2015, Minute but constant morphological differences within members of Stenothoidae: the Stenothoe gallensis group with four new members, keys to Stenothoe worldwide, a new species of Parametopa and Sudanea n. gen. (Crustacea: Amphipoda), Journal of Natural History 49 (37), pp. 2309-2377 : 2318-2320

Stenothoe cattai Stebbing, 1906

( Figure 2 ; Table 1)

Probolium polyprion Catta, 1876: 15 pl. 2 fig. 1 Stenothoe cattai Stebbing 1906: 195 , Chevreux & Fage, 1925: 132, fig. 131; Lincoln, 1979: 202 fig. 92; Krapp-Schickel, 2013a: 139, fig. 11

Stenothoe gallensis Krapp-Schickel, 1976: 15 , fig. 14–16; 1993: 701, fig. 481 non Stenothoe gallensis Walker, 1904: 261 , pl. 3, fig. 19 non S. cattai Chevreux & Fage, 1925: 132 , fig. 131 (see S. eduardi Krapp-Schickel, 1976 )

non Stenothoe cattai Reid, 1951: 230 , fig. 28

Type locality

Marseille, Mediterranean.

Material examined

See Krapp-Schickel (2013a, 141).

YPM IZ 500281 Bermuda, more than 50 specimens without detailed locality, algae .

YPM IZ 20388 , 2 specimens, Bermuda, North Rock , coral rubble 9 m depth, 2/I/1987 coll E. Lazo-Wasem .

Diagnosis

Length 3–4 mm. Gn 2 male propodus palm with dense but short setae, dactylus with few very short setae; carpus posterior margin not much rounded. Gn 2 female propodus with small triangular protuberance. U 3 many spines along upper margin of ramus art 1; art 2 only distally upwardly bent, never geniculate, little sculptured.

Remarks about various authors

The description of Stebbing’ s new species of 3 mm is very sparse; the hint to Stenothoe valida ‘partim’ described by Della Valle (1893) is not very helpful, as on p. 566 in Della Valle Gn 2 male propodus is described (and illustrated in t. 58) with one distal tooth, exactly as S. valida should have, but not the new species. Stebbing erected this species after the description and illustration of Probolium polyprion (name preoccupied) by Catta 1876, but Catta himself synonymises his species with Probolium megacheles of Heller, 1866, which is again a synonym of Stenothoe valida (see Krapp-Schickel 1974 who checked the type material).

Looking finally at the quite detailed illustrations, the most helpful character for this species is not illustrated: U 3 ramus article 1 has in S. valida only distal, but no marginal spines (always also marginal ones in the Mediterranean–Atlantic material, see Krapp-Schickel 1976, p. 15, fig. 14–16, 1993, p. 702, fig. 481; Lincoln 1979, p. 202, fig. 92). Gn 1, although illustrated with a rectangular propodus instead of a regularly rounded one, has a short merus and triangular carpus, which never is the case in S. valida ; thus, it should correspond to the Mediterranean material until now called S. gallensis .

Stebbing offers only ‘Mediterranean’ as type locality, but the type locality of Catta’ s species is Marseille, and the material was taken from the keel of a ship coming from Pondicherry ( India) and the Cape of Good Hope. Perhaps this fact is one of the reasons that S. cattai has been given so quickly in synonymy with S. gallensis , a species described from Ceylon. Otherwise, S. valida is well known as preferring harbours, and thus would have ecologically fitted perfectly.

Original description after Stebbing (1906): Length 3 mm vs 5 mm in Lincoln (1979) (henceforth abbreviated as ‘L.’), 4 mm in Chevreux and Fage (1925; henceforth abbreviated ‘Ch&F’), 3–3.5 mm in Krapp-Schickel (1993; henceforth abbreviated ‘K-S’). U 3 peduncle a little longer than the ramus (vs clearly shorter in L. and Ch&F, while in K-S., p. 702, fig. 481, U 3 male has a shorter peduncle, U 3 female a longer one), ramus art 2 ‘geniculate’ (always straight but only distally somewhat bent in all cited authors).

The description in Chevreux & Fage (1925, p. 132, fig. 131) corresponds well with the one by Lincoln (1979, p. 202, fig. 92) except for Gn 1 where the carpus is shorter in L. (l = b, vs l> b in Ch&F). Gn 2 female shows a triangular acute hump in the middle of the convex palm after Ch&F (p. 132, fig. 131), which is shown in K-S for ‘juv. male’. But all authors report many spines along the upper margin of U 3 ramus art 1, a unique character of this species within the S. gallensis group.

Distribution

Mediterranean, Atlantic.

Figures

Figure 2. Habitus of Stenothoe cattai Stebbing, 1906; photo taken by F. Costa from the surroundings of Messina (Sicily, Mediterranean).