Nebalia strausi Risso, 1826

Nebalia strausi Risso, 1826 View in CoL

Material examined. Ireland. 1♂, 3♀ , Kilkieran Bay, Co. Galway, 53°19.548’N 009°38.9165’W, 7.9 m, sandy gravel, 15.x.2010 GoogleMaps . 4♂, 4♀, Kingstown Bay, Co. Galway, 53°30.905’N 10°7.6979’W, 10 m, gravelly muddy sand, 16.x.2010 GoogleMaps . 3♀, Valentia Island, Co. Kerry, 51°53.819’N 10°18.786’W, 4 m, muddy sandy gravel, 16.ix.2010 ( NMINH: 2016.1.5, 1♀) GoogleMaps . 1♀ GoogleMaps , Valentia Island, Co. Kerry, 51°53.2439’N 10°21.948’W, 6 m, maërl, 16.ix.2010 ( NMINH: 2016.1.4, 1♀) GoogleMaps . 1♂, 5♀ GoogleMaps , Ahabeg, Bantry Bay, Co. Cork, at edge of stocked salmon farm cage located at 51°39.7302’N 009°45.1727’W, 20–23.4 m, mud with broken shell, 4.ix.2012 ( JM:2014, 1♂, 4♀) GoogleMaps . 1♂ GoogleMaps adult, Glinsk, Mulroy Bay, Co. Donegal, 55°12.1368’N 007°47.0682’W, 8–15 m, medium sand with both live and dead maërl, 14.viii.2012 GoogleMaps . 1♂ adult, Millstone, Mulroy Bay, Co. Donegal, 50 m from stocked salmon farm, 55°11.4205’N 007°45.388’W, 5–12.9 m, medium sand with maërl gravel, 15.viii.2012 ( JM:2014, 1♂) GoogleMaps .

British and Irish Distribution. South-west, west, and north of Ireland (Co. Cork, Co. Kerry, Co. Galway and Co. Donegal) and Guernsey ( Dahl, 1985) ( Fig. 1A View Figure 1 ).

Distribution beyond the study area. Gulf of Naples, Italy (type locality), Eastern Atlantic, from the north-west coast of France to St. Helena ( Dahl, 1985). Western Mediterranean ( Dahl, 1985). Eastern Mediterranean ( Koçak and Katagan, 2006; Koçak et al., 2007). Concarneau, Brittany, France (J.M.C. Holmes, pers. comm.).

Ecology. Coarse sediments, from gravel to coarse sand at depths of 12.7–15.2 m, Total Organic Matter (% TOM) 0.6–4.9 ( Moreira et al., 2009a). Maërl, medium sand to mud at depths of 4–23.4 m, % TOM 2.92–18.93 (present study).

Remarks. Nebalia strausi is recorded for the first time from Irish waters. Records of N. strausi to date suggest a southerly distribution with the specimens from Mulroy Bay, Co. Donegal, representing the northernmost extent of its range. Features distinguishing N. strausi from other species of Nebalia within the North-East Atlantic include distally acute denticles on the posterior margin of pleonites 6 and 7, in conjunction with an antennular flagellum with more than 10 articles and the exopod of the 2nd maxilla barely extending past the proximal article of the endopod.However, research (Moreira et al., 2004; Koçak et al., 2010) has shown that specimens of N. strausi from different localities can exhibit variation in a number of characters including the shape of the anal scales and the denticles of the posterior border of pleonites 6–7. Koçak et al.(2011) suggested that the existence of cryptic species cannot be ruled out for N. strausi .