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Here we presentAustropallene halanychisp. nov., a new species of pycnogonid within the family Callipallenidae (Pycnogonida), collected from the Ross Sea, Antarctica. While retaining key morphological features known for the genusAustropalleneHodgson, 1915a, the new species is distinguished from congeners by its much larger size, along with the combined absence of a denticle on the inner surface of the fixed finger of the chelifore claw along with the presence of small conical outgrowths where the fixed finger of the chelifore claw meets the movable finger on both the dorsal and ventral sides, and also the ability to fully close the chelifore claw. Additionally, the complete mitochondrial genome ofA. halanychiis consistent with other members of the genusAustropallenein terms of gene order and directionality. A phylogenetic tree consisting of mitochondrial protein-coding gene data placesA. halanychias sister toAustropallene cornigera(Möbius, 1902). Additionally, a phylogenetic tree constructed using partial COI data from other callipallenids placed the new species in a clade containing the genusAustropallene. The combination of molecular data in addition to key morphological differences from similar species in the genus leaves no doubt that the new taxon is a new Antarctic species ofAustropallene.
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The Scaly Notothen Trematomus loennbergii a new host, and the Ross Sea, Antarctica, a new locality for dermal X‑cell parasites Notoxcellia spp.
Abstract Pathogens affecting Antarctic fishes remain mostly unknown and are largely limited to the description of macroparasites such as leeches and endoparasitic worms. Fish, however, occupy a crucial role in the functioning of the Antarctic ecosystem and deterioration of their health can alter the entire Antarctic food chain. In recent years, several studies have identified novel viruses and unicellular parasites affecting the health of notothenioid fishes. Among those, the unicellular parasitic family Xcellidae has received attention following the discovery of an unprecedented disease outbreak in a fjord on the Western Antarctic Peninsula. This pathological situation was caused by a novel X-cell genusNotoxcellia. Soon thereafter, an additional X-cell genus,Cryoxcellia, was described infecting the Bald NotothenTrematomus borchgrevinkiin the Ross Sea. These studies raised awareness and drew observers’ and researchers’ attention to pathologies in Antarctic fishes. Here, we report that during a 2023 Ross Sea shelf survey, a specimen of the Scaly NotothenTrematomus loennbergiidisplaying skin lesions reminiscent ofNotoxcelliainfection had been ingested by an Antarctic ToothfishDissostichus mawsoniand was recovered from its stomach. Molecular analyses confirmed the presence ofNotoxcelliasp. X-cell parasites in the fish’s lesions. This new case of X-cell disease suggests thatNotoxcelliaspp. may have a circumpolar distribution and stresses the need for monitoring Antarctic fish health similar to surveillance protocols for Antarctic birds and marine mammals.
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- Award ID(s):
- 2232891
- PAR ID:
- 10614389
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Polar Biology
- Volume:
- 48
- Issue:
- 2
- ISSN:
- 0722-4060
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1007/s00300-025-03379-5
