MtDNA markers reveal the existence of allopatric evolutionary lineages in the threatened lampreys Lampetra fluviatilis (L.) and Lampetra planeri (Bloch) in the Iberian glacial refugium

Abstract

The Iberian Peninsula has been identified as an important glacial refugium during the Pliocene and Pleistocene epochs for the genus Lampetra, providing intermittent refuge and postglacial opportunities for colonization and expansion. We used mitochondrial DNA markers to investigate the processes that have shaped present-day genetic constitution of the genus Lampetra within the Iberian Peninsula. We surveyed 1,173 bp of the cytochrome b gene and 829 bp of the genes ATPase subunits 6 and 8 in 233 individuals of Lampetra fluviatilis (L.) and Lampetra planeri (Bloch) from 21 localities along their distribution range in the Iberian Peninsula. We identified four highly divergent allopatric evolutionary lineages that evolved by fragmentation during the Pliocene and Pleistocene likely driven by environmental factors, namely regional geomorphic events. The high level of genetic divergence between the four lineages suggests that sufficient time has apparently passed by to originate a complex of incipient or cryptic resident species and allows the definition of four evolutionary significant units (ESUs) for L. planeri and one ESU for L. fluviatilis. These findings have important consequences for the interpretation of refugia biological diversity and have major implications on the conservation of these threatened species.

Influence of macrohabitat preferences on the distribution of European brook and river lampreys: Implications for conservation and management

“…L. fluviatilis and L. planeri coexist in only 30% of the rivers assigned with the maximum level of conservation priority. The rivers assigned with the highest priority of conservation were associated with the respective evolutionary significant unit (ESU), as identified in Mateus et al (2011b) study. Following this procedure, the river stretches assigned with the maximum conservation priority belonging to the Sado river basin were associated to the ESU-I; the ones belonging to the Nabão sub-river basin were associated to the ESU-II; the ESU-III groups the river stretches assigned with the maximum conservation priority from the Vouga river basin plus the Mangas stream (system belonging to the small independent streams between Douro and Vouga river basins); the ESU-IV embraces the Inha river, in Douro river basin, the rivers assigned with the maximum conservation priority from the Mondego and Lis river basins, the S. Pedro stream (system belonging to the small independent streams of Oeste) and the rivers assigned with the maximum conservation priority from the Tejo river basin, with exception for the Nabão sub-river basin.…”

“…The high genetic diversity observed in Iberian Peninsula Lampetra populations, where four highly divergent allopatric evolutionary lineages were identified, is probably the result of refugial persistence and subsequent accumulation of variation over several ice ages, whereas the low levels of genetic diversity observed in central and northern Europe should reflect a rapid postglacial colonization (Mateus et al, 2011b). The high level of genetic divergence between the four lineages identified in the Iberian Peninsula suggests that sufficient time has apparently passed by to originate a complex of incipient or cryptic resident species which allowed the definition of four evolutionary significant units (ESUs) for L. planeri and one ESU for L. fluviatilis (Mateus et al, 2011b). River stretches with the higher priority of conservation are identified in Table 3.…”

“…Considering the restricted distribution of L. fluviatilis in Portugal (already extinct in Spain), as well as the highly fragmented Portuguese populations of L. planeri (with restricted distribution in Spain), in addiction to all the threats that both species are subject (see next paragraph), it is of great importance the effective conservation of the Portuguese populations of this genus, with the risk of, otherwise, losing the southern populations of both species. In addition, genetic diversity attained for the Iberian glacial refugia is higher than that found for the rest of the distribution area of both species (Espanhol et al, 2007;Mateus et al, 2011b), thus, failure in conservation strategies would result in the loss of genetic diversity and unique evolutionary lineages of the Iberian Peninsula.…”

“…in Portugal (Cabral et al, 2005;Espanhol et al, 2007;Mateus et al, 2011b). Lampreys occur from the Inha river (a tributary of the Douro river basin) in the north, to S. Domingos stream (Sado basin) in the south.…”

“…The importance of historical factors in the distribution of freshwa- Table 3 Rivers stretches designated with the higher level of priority with the indication of the presence (Â) or absence of Lampetra planeri and Lampetra fluviatilis. River stretches belonging to the evolutionary significant units (ESUs) identified in Mateus et al (2011b) Mateus et al (2011b), albeit, due to the proximity to others ESU within the same watershed it is assumed that they belong to the same evolutionary significant unit.…”