Eurycercus longirostris

Hann, 1982

Eurycercus longirostris is a Holarctic cladoceran first described by Hann in 1982. A 2011 taxonomic revision synonymized E. vernalis with E. longirostris due to lack of morphological and genetic justification for their separation. The has a broader distributional range than previously recognized and belongs to the subgenus Eurycercus (Eurycercus). As a member of the Eurycercidae , it shares characteristics with other chydorid-like cladocerans including a rounded and specialized feeding appendages.

Pronunciation

How to pronounce Eurycercus longirostris: //ˌjʊ.ɹɪˈsɜː.kəs ˌlɒn.dʒɪˈrɒs.trɪs//

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Identification

Eurycercus longirostris can be distinguished from by features characteristic of the subgenus Eurycercus (Eurycercus), including the presence of a keel passing through the entire of the and pores located on a prominent transverse fold. The specific epithet 'longirostris' suggests an elongated , though precise diagnostic characters distinguishing it from other Eurycercus require examination of parthenogenetic female . It differs from species in the former subgenus Bullatifrons (now synonymized) by the full-length median keel versus a keel restricted to the carapace dorsum.

Habitat

Freshwater environments in the Holarctic region. As a member of Eurycercidae, it likely inhabits of lakes and ponds, though specific preferences are not explicitly documented in available sources.

Distribution

Holarctic distribution, with records from the Nearctic region (North America) including Alaska and potentially broader range than previously known based on 2011 revision. Specific localities include areas where E. vernalis was formerly reported, now synonymized under this .

Similar Taxa

Eurycercus vernalisFormerly described as separate by Hann (1982), but synonymized with E. longirostris in 2011 revision due to lack of morphological and genetic differentiation.
Eurycercus macracanthusCongeneric in the same subgenus with similarly broadened Holarctic distribution; distinguished by specific morphological features of the and pores.
Eurycercus (Bullatifrons) speciesFormerly separated subgenus characterized by posteriorly restricted keel and bubble-like projection of pores without prominent transverse fold; now synonymized with E. (Eurycercus) based on phylogenetic and morphological evidence.

More Details

Taxonomic History

The has undergone significant taxonomic revision. Originally described by Hann in 1982 alongside E. vernalis, the two were later determined to represent the same species. The 2011 revision by Kotov and colleagues also resulted in synonymization of the subgenus Bullatifrons with Eurycercus (Eurycercus), affecting the of this species.

Phylogenetic Position

COI supports the placement of E. longirostris within the subgenus Eurycercus (Eurycercus) and does not support separation of the former subgenus Bullatifrons, leading to the emended subgenus concept.