Dexamine filiola, Krapp-Schickel, 2013

Krapp-Schickel, T., 2013, New or amended data on Mediterranean Amphipoda: genera Dexamine, Ericthonius and Stenothoe, Zootaxa 3613 (2), pp. 125-145 : 126-130

Dexamine filiola . sp. n

Fig. 2–4

Bellan-Santini, 1982: 222–224, fig. 151–152 sub Dexamine spinosa

Type material. Holotype: fem. ov. 3 mm, Portovenere (Liguria, Italy) Cystoseira 2m depth, July 1966; T. Krapp- Schickel coll.; slide MVRCr 7604.

Paratype: fem. with embryos, 5mm, same locality, same collector; in alcohol at the Verona Museum.

Additional material (all in the alcohol collection at the Verona Museum):

1 fem. ov. 4mm, 10 juveniles 3 mm, Portovenere (Liguria, Italy) Cystoseira 2m depth, July 1966; T. Krapp- Schickel coll. 2 ad. 3mm, 20 immat. Rovinj , Val Faborsa, Cymodocea nodosa 10–25m, July 1967, T. Krapp- Schickel coll. Napoli-Ischia , Porto, several fem. 3–4 mm; 29.3. 1969; U. Schiecke coll. Napoli-Ischia , Secca di Forio, 50m, 2 fem.; 1969; U. Schiecke coll. Napoli-Ischia , Vervece, 30–35m, 1 fem.; 1969; U. Schiecke coll.

Sardegna, Capo Caccia 0–5m: 1 fem. ov. 3mm, 1 fem. ov. 3–4mm, 8–10 m, U. Schiecke coll. Malta 1 fem. ov. 3mm , 3–10 m; U. Schiecke coll. Izmir, 1 fem. ov. 4mm, leg. KocataŞ.

Description of female (main differences to Dexamine spinosa given in bold letters).

Length: 3–6 mm (vs. D. s. 9–14 mm).

Head: Rostrum short, cephalic lobes triangular, acute; eyes large, reniform, brown or black (vs. whitishreddish, see photo of a living D. spinosa , Fig. 1 ).

A1 peduncular art 1 produced distally into acute process, art 2 twice as long as art 1. A1 clearly> A2. Mouthparts like in Dexamine spinosa .

Peraeon thickened. Coxae distally setose (vs. D. s. smooth). Cx 2–4 also facially beset with short setae.

Gn1 basis curved, moderately setose; propodus> carpus. Gn2> Gn1, carpus ≥ propodus.

P5–7 usually twisted, clearly diminishing in length, basis hind margin moderately (vs. densely) setose. P6 hind margin straight (vs. strongly excavate).

Pleon: Segments 1–3 dorsally produced into backwards pointing tooth. Urosome segment 1 produced into a humped tooth, segment 3 with two crests armed with 2 spines. U1 peduncle = subequal rami; U2 outer ramus <inner one. U3 rami slender, lanceolate, irregularly beset with spines, rami subequal.

Telson: 3–4 lateral spines (often in pairs) and one distal spine (vs. D. s. 2–3 single lateral ones).

Remarks. The drawings in Bellan-Santini, 1982, showing material from Marseille, match this new species in the details of the setose coxae (also facially,- never mentioned in other descriptions) and the straight posterior margin of P6 basis, but the body length is told as " 9–12mm ". The colour of the eyes is given in Lincoln (1979) as white, in Chevreux & Fage (1925) as brown, in Bellan-Santini (1982) as red, white or black.

Etymology. the Latin word filia means daughter, and filiola is the diminutive, "little daughter", alluding the much smaller size comparatively to the morphologically so similar species Dexamine spinosa (Montagu) .

Figures

FIGURE 1. Dexamine spinosa (Montagu, 1814) habitus of live specimen from Messina; Francesco Costa phot.

FIGURE 2. Dexamine filiola sp. n.. 3mm Malta: Gn1, Gn1' = first gnathopod, partly enlarged; P5–7= peraeropods 5–7.

FIGURE 3. Dexamine filiola sp. n. Gn2 ov. female 3mm from Malta; Gn2 ov. female 6mm from Napoli.

FIGURE 4. Dexamine filiola sp. n. fem. 6mm from Napoli: P5–7 = peraeopod 5–7 (twisted); Ep1–3 = epimeral plate 1–3; U3 = third uropod; T = telson; Us = urosome.