Amphipod crustaceans (Corophiidea and Gammaridea) associated with holdfasts of Macrocystis pyrifera from the Beagle Channel (Argentina) and additional records from the Southwestern Atlantic Author Alonso, G. M. text Journal of Natural History 2012 2012-08-31 46 29 - 30 1799 1894 http://dx.doi.org/10.1080/00222933.2012.692825 journal article 10.1080/00222933.2012.692825 1464-5262 5200405 Gammaropsis (Paranaenia) typica ( Chilton, 1884 ) Paranaenia typica Chilton, 1884: 259–260 , pl. 19, fig. 1. Gammaropsis typica : Alonso, 1980: 9–10 , pl. 6. Gammaropsis (Paranaenia) typica : J.L. Barnard and Karaman, 1991: 192 ; De Broyer et al., 2007: 273 . Material examined Argentina ; Beagle Channel, northern Isla Despard , 54 ◦ 52 ′ S , 68 ◦ 10 ′ W , 8–12 m depth , colls. D. Aureliano and A. Ferlito , don. G. Lovrich , 19 March 1999 : 2 ovig. ♀♀ 4.8 and 4.9 mm , MACN-In 38514a; 1 ovig. ♀ 5.9 mm , 2 ♂♂ 5.95 and 6 mm , MACN-In 38514b. Same location, same colls., 24 May 1999 : 2 ovig. ♀♀ 5.8 and 6.2 mm , 1 ♀ 5.05 mm , 5 ♂♂ 5–5.15 mm , MACN-In 38515a; 2 ♂♂ 4.9 and 5.25 mm , MACN-In 38515b; 2 ovig. ♀♀ 5 and 5.8 mm , 2 ♀♀ 4.5 and 5.95 mm , 2 ♂♂ 5 and 5.25 mm , MACN-In 38515c; 1 ovig. ♀ 5 mm , 1 ♀ 4 mm , MACN-In 38515d. Same location, same colls., 27 May 1999 : 1 ovig. ♀ 5.3 mm , 3 ♂♂ 3.8–5 mm , MACN-In 38516a; 3 ♀♀ 5.15–6 mm , 2 ♂♂ 5.2 and 6 mm , MACN-In 38516b; 5 ♀♀ 5–5.75 mm , 5 ♂♂ 4.9–5.2 mm , MACN-In 38516c. Same location, same colls., 5 August 1999 : 2 ♀♀ 5 and 5.1 mm , 2 ♂♂ 4 and 6 mm , MACN-In 38517a; 3 ♀♀ 4.2–5 mm , 1 ♂ 4.75 mm , MACN-In 38517b; 2 ♀♀ 4.3 and 5 mm , 1 ♂ 5.5 mm , MACN-In 38517c. Same location, same colls., 11 August 1999 : 1 ovig. ♀ 6 mm , 3 ♀♀ 5.7–6 mm , 8 ♂♂ 5.7–7 mm , MACN-In 38518a; 1 ovig. ♀ 6.05 mm , 1 ♂ 7 mm , MACN-In 38518b; 6 ovig. ♀♀ 5.7–7 mm , 1 ♀ 5.15 mm , 10 ♂♂ 5.15–6.15 mm , MACN-In 38518c; 1 ♀ 5.25 mm , MACN-In 38518d; 2 ovig. ♀♀ 5.9 and 6.3 mm , 3 ♀♀ 4.25–5.7 mm , 6 ♂♂ 5–6.5 mm , MACN-In 38518e; 4 ovig. ♀♀ 6.9–7 mm , 2 ♀♀ 7 mm , 12 ♂♂ 5.85–7.05 mm , MACN-In 38518f. Same location, same colls., 1 November 1999 : 7 ovig. ♀♀ 5.5–6.6 mm , 6 ♀♀ 6.2–7 mm , 7 ♂♂ 5.8–7.5 mm , MACN-In 38519a; 3 ovig. ♀♀ 6–7.1 mm , 3 ♂♂ 5–7.1 mm , MACN-In 38519b; 2 ovig. ♀♀ 5.5 and 5.6 mm , 3 ♂♂ 5.6–6.8 mm , MACN-In 38519c; 3 ovig. ♀♀ 6–6.15 mm , 2 ♀♀ 6 and 6.15 mm , 3 ♂♂ 5–6.9 mm , MACN-In 38519d. Same location, same colls., 10 November 1999 : 2 ovig. ♀♀ 5 and 5.8 mm , 1 ♀ 6.2 mm , 5 ♂♂ 5.3–6.15 mm , MACN-In 38520a; 2 ovig. ♀♀ 5.5 and 6 mm , 1 ♀ 4.6 mm , 5 ♂♂ 4.7–5 mm , MACN-In 38520b; 2 ovig. ♀♀ 5.3 and 6.7 mm , 1 ♂ 5 mm , MACN-In 38520c; 9 ovig. ♀♀ 5.1–7 mm , 10 ♂♂ 6.2–7.1 mm , MACN-In 38520d; 8 ovig. ♀♀ 6–6.35 mm , 2 ♂♂ 5.5 and 6 mm , MACN-In 38520e. Same location, same colls., 10 February 2000 : 8 ovig. ♀♀ 6–7.1 mm , 7 ♀♀ 6.2–7 mm , 16 ♂♂ 5–7.4 mm , MACN-In 38521a; 5 ovig. ♀♀ 5–6.75 mm , 3 ♀♀ 6–6.8 mm , 5 ♂♂ 5–6.9 mm , MACN- In 38521b; 3 ovig. ♀♀ 6–7 mm , 1 ♀ 5.4 mm , 7 ♂♂ 5.5–7.25 mm , MACN-In 38521c; 5 ovig. ♀♀ 5.5–6.95 mm , 6 ♀♀ 5.5–7 mm , 7 ♂♂ 5.9–6.8 mm , MACN-In 38521d; 7 ovig. ♀♀ 5.9–7 mm , 2 ♀♀ 5.95 and 6.6 mm , 8 ♂♂ 5–6.95 mm , MACN-In 38521e; 5 ovig. ♀♀ 5.8–7 mm , 8 ♀♀ 6–6.9 mm , 14 ♂♂ 6–7 mm , MACN-In 38521f. Same location, same colls., 14 February 2000 : 1 ovig. ♀ 5.05 mm , 7 ♀♀ 5–7 mm , 4 ♂♂ 5–7 mm , MACN- In 38522a; 1 ♀ 6.3 mm , 1 sex indet. 3.7 mm , 1 ♂ 5.8 mm , MACN-In 38522b. Same location, same colls., 2 May 2000 : 6 ovig. ♀♀ 5.2–6.5 mm , 10 ♀♀ 5–6.7 mm , 15 ♂♂ 5–6 mm , MACN-In 38523a; 12 ♀♀ 5.2–6.3 mm , 3 ♂♂ 5.7–6 mm , MACN-In 38523b; 6 ovig. ♀♀ 5.3–7 mm , 6 ♀♀ 4.85–7 mm , 6 ♂♂ 4.9–6.4 mm , MACN-In 38523c; 5 ovig. ♀♀ 5.1–6.2 mm , 8 ♀♀ 5–6 mm , 11 ♂♂ 4–6 mm , MACN-In 38523d. Same location, same colls., 29 May 2000 : 3 ♀♀ 5.5–6.25 mm , 5 ♂♂ 4.6–6 mm , MACN-In 38524a; 2 ovig. ♀♀ 6 and 6.05 mm , 11 ♀♀ 4.8–6.9 mm , 14 ♂♂ 5.3–6.8 mm , MACN-In 38524b; 4 ♀♀ 4.85–5.7 mm , 2 ♂♂ 4.8 and 5.6 mm , MACN-In 38524c; 4 ovig. ♀♀ 5–5.8 mm , 13 ♂♂ 5–6.1 mm , MACN-In 38524d; 3 ♀♀ 5.35–5.8 mm , 1 ♂ 5.75 mm , MACN-In 38524e . New catalogue numbers Argentina ; Santa Cruz province , Ría Deseado , approx. 47 ◦ 45 ′ S , 65 ◦ 55 ′ W , Península Foca : 2 ovig. ♀♀ 4 and 4.25 mm , 10 March 1978 , MACN-In 38525; Punta Cavendish : 1 ovig. ♀ 4 mm , 3 ♂♂ 4–4.2 mm , 28 March 1978 , MACN-In 38526; Dos Hermanas : 2 ovig. ♀♀ 4.1 and 4.9 mm , 1 ♀ 4.5 mm , 3 ♂♂ 4–4.5 mm , 18 October 1978 , MACN- In 38527; Península Foca : 2 ovig. ♀♀ 3.2 and 3.8 mm , 1 ♀ 3.2 mm , 1 ♂ 3 mm , 21 February 1979 , MACN-In 38528 ; Isla Larga : 2 ovig. ♀♀ 3 and 3.8 mm , 1 ♂ 3.3 mm , 21 March 1979 , MACN-In 38529; Punta Cavendish: 1 ♀ 2 mm (damaged), 23 April 1979 , MACN-In 38530; 1 ovig. ♀ 4.25 mm , 1 ♂ 4 mm , 3 March 1980 , MACN-In 38531; Baliza Sorrel: 1 ovig. ♀ 3.25 mm , 2 ♂♂ 3.5 and 3.9 mm , 20 March 1980 , MACN-In 38532 . Remarks This species agrees with the description and figures of J.L. Barnard (1972b) . The specimens from Santa Cruz display the developed proximal process of the palm of the male second gnathopod when they reach approximately 4 mm body length; the present specimens show the palmar process well developed when the individuals attain about 6 mm length. Gammaropsis (Paranaenia) typica ( Chilton, 1884 ) , well represented in southern South America, was found associated to M. pyrifera in the Argentine sector of the Beagle Channel.