Ericthonius species

Krapp-Schickel, T., 2013, New or amended data on Mediterranean Amphipoda: genera Dexamine, Ericthonius and Stenothoe, Zootaxa 3613 (2), pp. 125-145 : 137-139

Key to the five Mediterranean Ericthonius species (males only)

1. Eyes small. Gn 1 basis with knob-like process on posterior margin; Cx 2 not broader than deep, often rectangular............................................................ E. brasiliensis (Dana, 1855) (7 mm) type locality Rio de Janeiro

- Eyes large, Gn 1 basis lacking knob-like process; Cx 2 usually broader than deep and distal margin regularly rounded...... 2

2. Gn 2 male carpus with only one slender simple tooth (which may have a small accessory tooth)........................................................................ E. difformis Milne Edwards, 1930 (5 mm), type locality " Brittany " - Gn 2 male carpus with two divergent teeth (in very old males inner tooth worn down to a rounded process)..............3

3. Gn 2 male carpus with two teeth of about the same length; P 3, 4 basis widest in the middle, narrowing distally........................................................... E. punctatus (Bate, 1857) (7 mm) type locality Oxwich Bay , Wales

- Gn 2 male carpus outer tooth much longer than inner one; P 3, 4 basis on distal end not narrowing...................... 4

4. G1 basis about 3x as long as wide; Gn2 carpus and propodus never longer than twice the breadth, basis about 3x as long as wide; in adult males basis P5 posterodistally with a deep excavation, followed by a prolungate lobe...................................................................... E. didymus sp.n. (3.5– 6 mm), type locality Venezia, Adriatic Sea

- Gn1 basis about 2x as long as wide; Gn2 carpus and propodus clearly longer than twice the breadth, basis more than 3x longer than wide; in adult males basis P5 posterodistally with a corner, lacking any produced lobation................................................................ .. E. argenteus Krapp-Schickel, 1994 (2–3.5 mm), type locality: Kreta, Grece