Data from: Differential response to heat-stress among evolutionary lineages of an aquatic invertebrate species complex

Under global warming scenarios, rising temperatures can constitute heat
stress to which species may differentially respond. Within a described
species, knowledge on cryptic diversity is of further relevance, as
different lineages/cryptic species may differentially respond to
environmental change. The Brachionus calyciflorus species complex
(Rotifera), which was recently described using integrative taxonomy, is an
essential component of aquatic ecosystems. Here, we tested the hypothesis
that these (formerly cryptic) species differ in their heat tolerance. We
assigned 47 clones with nuITS1 and mtCOI markers to evolutionary lineages,
now named Brachionus calyciflorus sensu stricto and Brachionus fernandoi.
We selected 15 representative clones, and assessed their heat tolerance as
a bi-dimensional phenotypic trait affected by both intensity and duration
of heat-stress. We found two distinct groups, with B. calyciflorus sensu
stricto clones having higher heat tolerance than the novel species B.
fernandoi. This apparent temperature specialization among former cryptic
species underscores the necessity of a sound species delimitation and
assignment, when organismal responses to environmental change are
investigated.