Identifying biochemical phenotypic differences between cryptic species

Abstract

Molecular genetic methods can distinguish divergent evolutionary lineages inwhat previously appeared to be single species, but it is not always clear what functional differences exist between such cryptic species. We used a metabolomic approach to profile biochemical phenotype (metabotype) differences between two putative cryptic species of the earthworm Lumbricus rubellus. There were no straightforward metabolite biomarkers of lineage, i.e. no metabolites that were always at higher concentration in one lineage. Multivariate methods, however, identified a small number of metabolites that together helped distinguish the lineages, including uncommon metabolites such as N1-trimethyllysine, which is not usually found at high concentrations. This approach could be useful for characterizing functional trait differences, especially as it is applicable to essentially any species group, irrespective of its genome sequencing status.

External diversity is restrained by internal conservatism: New nudibranch mollusc contributes to the cryptic species problem

“…The present study thus can be a significant contribution for the cryptic species problem because it reveals a remarkable case of multilevel character diversity in a common group within Europe, which externally can be considered as a cryptic species complex, whereas internally it is instead a group of “pseudocryptic” or taxonomically “normal” species and molecular data show congruence with the internal morphological features. Because there is ongoing discussion on plausibility of the distinction between “cryptic” and “pseudocryptic” species using both morphological characters and molecular markers (Heethoff et al., ; Karanovic et al., ; Liebeke et al., ; Schlick‐Steiner et al., ), the present notable finding may contribute to the general problem of revealing hidden biological diversity by molecular methods and appropriately furnishing these with diagnosable morphological features. This is especially important because this is an example from a very distinctive group of marine invertebrates.…”

“…First of all, there are several grades in cryptic diversity—from almost completely morphologically indistinguishable pairs of sibling species to complexes which may display minor, but still morphologically detectable differences termed as semi‐cryptic or pseudocryptic species (Amato et al., ; Knowlton, ; Saéz & Lozano, ). The existence of phenotypic differences previously considered to be insignificant leaves the possibility for developing an integrative systematics (Dayrat, ; Heethoff, Laumann, Weigmann, & Raspotnig, ; Padial, Miralles, De La Riva, & Vences, ; Schlick‐Steiner et al., ) when molecular characters are correlated with the morphology and other evidence (Liebeke et al., ). However, the distinction between “cryptic” and “pseudo‐cryptic” species is not always reliable and may be simply different observers’ evaluations of slight morphological differences (Karanovic, Djurakic, & Eberhard, ).…”

Pontoscolex corethrurus:a Homeless Invasive Tropical Earthworm?

“…Cryptic invasions occur frequently, often go unnoticed, and are hard to recognize. Also, it is known that cryptic species may display markedly different responses to a given stimulus or stressor (Liebeke et al 2014;Schult et al 2016;Morais and Reichard 2018 (Kille et al 2013;Liu et al 2017;Ponesakki et al 2017;Fernández-Marchán et al 2018). Last, potential symbionts may be found for each agrotype, including bacteria, nematodes, enchytraeids and other life forms associated with earthworms (Coates 1990;Fernández-Marchán et al 2018).…”

An integrative multidisciplinary approach to understanding cryptic divergence in Brazilian species of theAnastrepha fraterculuscomplex (Diptera: Tephritidae)

“…Recently diverged cryptic species complexes characterized by strong similarities represent a challenge to the use of morphological characters for the identification and delimitation of species (Bickford et al, 2007). Therefore, studies comprising multiple lines of evidence, such as DNA sequencing and metabolomic approaches, have been used to assist in the diagnosis of cryptic species (Lumley & Sperling, 2010;Yeates et al, 2011;Liebeke et al, 2014).…”