Epischura

Forbes, 1882

Species Guides

Epischura lacustris

Epischura is a of freshwater calanoid copepods in the Temoridae. The genus contains approximately 11 recognized , including the well-studied Epischura lacustris of North American lakes and the Epischura baikalensis of Lake Baikal. Species within this genus exhibit diverse feeding strategies ranging from omnivory to , with documented consumption of both phytoplankton and zooplankton prey. The genus has been proposed as with respect to Heterocope, with suggestions to transfer the Siberian species E. baikalensis and E. chankensis to the resurrected genus Epischurella.

Pronunciation

How to pronounce Epischura: /ˌɛpɪˈskjʊrə/

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Habitat

Freshwater lakes; primarily lacustrine environments. Epischura baikalensis is restricted to the pelagic zone of Lake Baikal with seasonal vertical distribution shifts.

Distribution

North America (E. lacustris, E. fluviatilis, E. massachusettsensis, E. nevadensis, E. vagans); Lake Baikal, Siberia (E. baikalensis, ); Siberian and Russian Far East lakes (E. smirnovi, E. udylensis, E. chankensis).

Diet

to predatory. Epischura lacustris has been documented consuming the Cryptomonas erosa, the rotifers Euchlanis dilatata and Polyarthra remata, and the cladocerans Bosmina longirostris, Ceriodaphnia reticulata, and Holopedium gibberum. Prey size selection occurs with smaller individuals consumed at higher rates.

Life Cycle

Epischura baikalensis exhibits a with under ice cover in February-March, naupliar stages I-VI in spring, copepodid stages C1-C5 through summer and autumn, and as late copepodid stages (C4-C5) and . Recent studies suggest E. baikalensis may have three per year with a possible 3-month winter embryonic from November to February.

Behavior

Epischura lacustris exhibits sophisticated predatory including distance sensing of prey, judgment of approach angle and prey speed, reorientation during attack, and variable handling responses. No true behavioral preference or switching between prey types has been demonstrated; diet includes all detectable, capturable, and ingestible prey. Vertical patterns vary seasonally in E. baikalensis, with concentration in upper layers during spring-summer and deeper distribution in autumn-winter.

Ecological Role

component of pelagic zooplankton in occupied lakes. Epischura baikalensis is a in Lake Baikal's zooplankton and a key primary consumer in the lake's central pelagic . As both phytoplankton consumers and of smaller zooplankton, in this occupy intermediate trophic positions.

Similar Taxa

HeterocopeProposed sister ; Epischura has been suggested as with respect to Heterocope based on phylogenetic analyses
EpischurellaResurrected proposed to contain the Siberian E. baikalensis and E. chankensis, which were formerly classified in Epischura