As a part of an ongoing long-term study on the biology of pack-ice seals in Antarctica, we had the opportunity to collect lice from Weddell seals (Leptonychotes weddelli). We did not find the original description of this host-parasite association. Antarctophthirus ogmorhini had previously been reported as a parasite for the Weddell seal, but the information is, to a certain extent, confusing. During the development of the present study, we had access to literature concerning the presence of A. ogmorhini on this host, which, to our knowledge, was not determined in any of the previous works on this species. We compared lice collected from Weddell seals with A. ogmorhini obtained from the type host, the leopard seal (Hydrurga leptonyx), and we found that both species can be distinguished. The main differences are the characteristic pattern of chaetotaxy in the dorsal side of the head in lice from Weddell seals, the size and form of the pseudopenis, and the distribution and size of the fringe of setae surrounding the genital opening. Considering the conservative morphology, and ecological and evolutionary features of sucking lice, we proposed that lice from Weddell seals constitute a new species. In the present work, we described and illustrated adults of this new species collected from Weddell seals during the austral summer of 2014 at the Danco Coast, Antarctic Peninsula.

Non-indigenous bryozoans are frequent components of biofouling assemblages in harbour environments worldwide. We performed a survey of artificial hard substrates in six harbours spanning 16 degrees of latitude along the coast of Argentina, from Ingeniero White (38º47′ S) to Ushuaia (54º48′ S). Microeciella argentina n. sp., distributed in warm-temperate waters of northern Patagonia and Buenos Aires Province, is described. The non-indigenous species (NIS) Callopora dumerilii, Smittoidea spinigera and Stephanollona boreopacifica are recorded here for the first time in the Southwest Atlantic. Their occurrence in fouling assemblages of warm-temperate harbours and their previous absence in these areas suggest that they probably arrived in Argentina by international shipping traffic. Callopora dumerilii is native to Europe and the northeast Atlantic. Smittoidea spinigera and Stephanollona boreopacifica are native to China and Korea, respectively. The morphological differences between S. spinigera and the Californian species S. prolifera, which is invading European harbours in the North Sea, are discussed. Bugula neritina, Bugulina flabellata, Cryptosula pallasiana and Fenestrulina delicia, common in harbours of Buenos Aires Province, are here recorded in Patagonia, highlighting the importance of regional shipping traffic to secondary spread of NIS. Arachnidium fibrosum, Buskia socialis, Anguinella palmata, Aetea cultrata, Bicellariella edentata and Exochella moyanoi, previously known from Brazil, and Hippothoa divaricata, are here recorded in Argentina. This study shows that warm-temperate harbours in Buenos Aires Province and northern Patagonia are particularly prone to the introduction of non-indigenous bryozoans.

The Anoplura (Phthiraptera) is composed of lice parasitizing mainly terrestrial mammals, but a few members have been able to adapt to the marine environment. The latter are included in the family Echinophthiriidae, a particular group infecting pinnipeds worldwide. They also are of the few insects that managed to survive in the ocean. The study of Antarctic echinophthiriids flourished in the 1960s, but in the last 50 years, no advance has been made. Revision of Antarctic echinophthiriids is part of ongoing research on the systematics, phylogeny and ecology of these lice. During the summer season of 2014, we had the opportunity to collect lice from crabeater seals captured at Cierva Cove in the northern sector of the Danco Coast, Antarctic Peninsula. Since its original description was incomplete and the holotypes were lost, here we redescribe Antarctophthirus lobodontis based on these specimens. The present material can be distinguished from other Antarctic Antarctophthirus species by the presence of four marginal long hairs and in the basis of the head a line of eight spines and three hairs above the last row of four spines. Also in the present work, we provide a key to the identification of the Antarctic species of Echinophthiriidae based on morphological characteristics.

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