Distribution and ecology of lampreys Lethenteron spp. in interior Alaskan rivers

Morphology-based taxonomic re-assessment of the Arctic lamprey, Lethenteron camtschaticum (Tilesius, 1811) and taxonomic position of other members of the genus

The lamprey genus Lethenteron Creaser & Hubbs, 1922 is widespread across Eurasia and North America, but the number and distribution of its constituent species is not firmly established. After a morphological examination of extant type material of the currently recognized species and their synonyms, Lethenteronmitsukurii (Hatta, 1901) is resurrected with Le.matsubarai Vladykov & Kott, 1978 as its junior synonym. Amongst nonparasitic species Le.reissneri (Dybowski, 1869) and Le.mitsukurii are confirmed as present in Japan and the former is also present on Sakhalin. An in-depth study of large samples of nonparasitic lamprey adults from Japan and Sakhalin Island is needed to determine whether the lower trunk myomere (< 66) individuals from these areas represent one or more undescribed species, or Le.mitsukurii, or Le.reissneri, or a mixture of these three alternatives. The material from the Anadyr Estuary identified by Berg (1931, 1948) as Lampetrajaponicakessleri has been re-identified as Le.camtschaticum and there is no evidence that Le.kessleri occurs there. Lethenteronreissneri is reported from the Angara River system, Yenisei River drainage, Russia. Lethenteronalaskense Vladykov & Kott, 1978 is provisionally considered to be a junior synonym of Le.kessleri (Anikin, 1905). Petromyzonernstii Dybowski, 1872, Ammocoetesaureus Bean, 1881, Petromyzondentex Anikin, 1905, Lampetramitsukuriimajor Hatta, 1911, and Lampetrajaponicaseptentrionalis Berg, 1931 are junior synonyms of Petromyzonmarinuscamtschaticus Tilesius, 1811. A key is provided to adults of the six species recognized as belonging in the genus Lethenteron.

Genetic variation and population structure among larval Lethenteron spp. within the Yukon River drainage, Alaska

The absence of information on genetic variation and population structure of lampreys Lethenteron spp. in the eastern part of their distribution limits our understanding of the migration ecology and spatial population genetic structure of the species. We examined genetic variation within and among three aggregations of Lethenteron spp. larvae in the Yukon River drainage, Alaska, using microsatellite genotypes. A total of 120 larval lampreys were genotyped at eight microsatellite loci. Global F_ST was 0.053 (95% CI 0.021-0.086), while pairwise F_ST values ranged from 0.048-0.057. Model-based Bayesian clustering analyses with sample locality priors (LOCPRIOR) identified three distinct, but admixed, genetic clusters that corresponded with the three aggregations. Estimates of contemporary gene flow indicate substantial reciprocal migration among sites consistent with no or low-fidelity natal homing. These results are largely in agreement with previous reports of historic and contemporary gene flow among Lethenteron spp. in other parts of their geographic distribution.