Morphological analysis of some cryptic species in the Acanthocyclops vernalis species complex from North America

Out of Alaska: morphological diversity within the genus Eurytemora from its ancestral Alaskan range (Crustacea, Copepoda)

“…In general, morphological divergences provide much less resolution for distinguishing sibling species within Eurytemora than molecular phylogenies or patterns of reproductive isolation (Lee, 2000;Lee & Frost, 2002;Skelly et al, in prep.). Many copepod species tend to exhibit morphological stasis, where populations are indistinguishable based on morphological characters, while showing large genetic divergences and reproductive isolation among populations (Carrillo et al, 1974;Dodson et al, 2003;Edmands & Harrison, 2003;Grishanin et al, 2005;Chen & Hare, 2008).…”

“…Morphological stasis appears to be a common problem in copepod systematics in general, where morphologically indistinguishable populations often show evidence of large genetic divergences and reproductive isolation (Carrillo et al, 1974;Lee & Frost, 2002;Dodson et al, 2003;Edmands & Harrison, 2003;Grishanin et al, 2005;Chen & Hare, 2008). For example, the copepod Eurytemora affinis exhibits rates of morphological evolution that are much slower than rates of molecular evolution (Lee & Frost, 2002).…”

Cryptic speciation in the cosmopolitan Epiphanes senta complex (Monogononta, Rotifera) with the description of new species

“…Cryptic speciation has been studied more extensively in other freshwater microinvertebrates such as Copepoda and Cladocera (e.g. Taylor & Hebert, 1992;Lee, 2000;Lee & Frost, 2002;Dodson et al, 2003;Penton et al, 2004;Kim et al, 2006) and many marine invertebrates (Knowlton, 2000). Genetic differentiation may be considerable due to reproductive isolation and/or geographic barriers to gene flow.…”

Recommendations for Taxonomic Submissions to Hydrobiologia

“…Woltereck (1909) used laboratory cultures of several forms of Daphnia to show that they were actually morphological variants ('cyclomorphosis') of one basic morphological form (Dodson, 1989). Laboratory cultures revealed that the major morphological character used to distinguish two Daphnia species was induced by predaceous Chaoborus larvae (Krueger & Dodson, 1981), and that the major morphological character used to distinguish two Acanthocyclops species were in fact variants of a single morphological form induced in response to temperature (and subject to phenotypic plasticity) (Dodson et al, 2003). Lee & Frost (2002) found that morphological variance (Q ST ) was much greater among wild-caught populations of the copepod Eurytemora affinis than among those reared in common-garden in the laboratory.…”

“…Cicchino et al (2001) used laboratory experiments to show that diaptomid copepod males and females, which had been described as different species, were actually able to mate and produce offspring. Cryptic (reproductively isolated but morphologically indistinguishable) species are frequently revealed by mating experiments (Knowlton, 2000;Lee & Frost, 2002;Dodson et al, 2003;Avise, 2004). Careful morphological analysis of cryptic species can sometimes reveal morphological differences among cryptic species, once the (biological) species have been revealed using mating experiments (Knowlton, 2000;Dodson et al, 2003).…”