Kidderia subquadrata

16. Kidderia subquadrata (Pelseneer, 1903) [Figs 8E–J] Cyamium subquadratum Pelseneer, 1903: 15, fig. 124 Material examined. • 233 spms, Stn. 4; • 3 spms, Stn. 9. Type locality. Two Hummock Island (Antarctic Peninsula), intertidally. Bathymetric distribution. Rocky intertidal. Substrate. Hard bottom, attached to stones. Geographical distribution. ANTARCTICA:Antarctic Peninsula. SUBANTARCTICA: -. SCOTIA ARC: South Shetland Islands. SOUTH AMERICA: -. Remarks. The taxonomic classification of this species proved to be difficult. The specimen illustrated in Engl (2012, pl. 10, fig. 3) as Lasaea consanguinea (E. A. Smith, 1877) with the same place of origin as our study area proved to be identical. However, Huber (2010, fig. on p. 263; 2015, p. 503) revised the identification and named the specimen illustrated in Engl (2012) as K. subquadrata. Engl himself revised his L. consanguinea in 2016 and identified it as Kidderia bicolor (E. von Martens, 1885). By revising the taxonomic questions and the genetic delimitation of the species, it was possible to determine that the Antarctic species is Kidderia subquadrata and the species found on the sub-Antarctic islands of Diego Ramirez, South Georgia and the Kerguelen Archipelago is Kidderia minuta Dall, 1876 (Levicoy et al. 2021a, b). The presence of other species of the genus (e.g. K. bicolor) could not be confirmed so far and requires a greater sampling effort (Levicoy et al. 2021a). Kidderia subquadrata is a valid species of Gaimardiidae, with family-typical dentition. We have found it frequently and exclusively in rock pools in subtidal depths. The species is already known from the Maxwell and Admiralty Bays. References. Arnaud et al. (1986), Huber (2010, 2015), Engl (2012), Bick & Arlt (2013), Aghmich et al. (2016), Levicoy et al. (2021a, b).