A closer look reveals hidden diversity in the intertidal Caribbean Fortuyniidae (Acari, Oribatida)

Abstract

A molecular genetic and morphometric investigation revealed the supposedly widespread Caribbean and Western Atlantic intertidal oribatid mite species Fortuynia atlantica to comprise at least two different species. Although there are no distinct morphological differences separating these taxa, COI and 18S sequence divergence data, as well as different species delimitation analyses, clearly identify the two species. Fortuynia atlantica is distributed in the northern Caribbean and the Western Atlantic and the new Fortuynia antillea sp. nov. is presently endemic to Barbados. Vicariance is supposed to be responsible for their genetic diversification and stabilizing selection caused by the extreme intertidal environment is suggested to be the reason for the found morphological stasis. The genetic structure of Fortuynia atlantica indicates that Bermudian populations are derived from the northern Caribbean and thus support the theory of dispersal by drifting on the Gulf Stream. Haplotype network data suggest that Bermudian and Bahamian populations were largely shaped by colonization, expansion and extinction events caused by dramatic sea level changes during the Pleistocene. A preliminary phylogenetic analysis based on 18S gene sequences indicates that the globally distributed genus Fortuynia may be a monophyletic group, whereas Caribbean and Western Atlantic members are distinctly separated from the Indo-Pacific and Western Pacific species.

The Phyloperiodic Approach Removes the “Cryptic Species” and Puts forward Multilevel Organismal Diversity

“…Recently, a number of significant contradictions in the use of the term "cryptic species" have been clearly shown [1][2][3][4][5][6][7][8][9]. Despite this, the term "cryptic species" is still widely used in biodiversity studies [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. It is important to note that the apparent "crypticity" has been indicated for the widest range of groups of organisms, including plants, fungi, animals, and unicellular and multicellular groups, as exemplified by the references above.…”

How mites surprise us

“…We have no doubt that other species will 'appear' within Eulohmanniidae when the group is viewed even more closely, through molecular studies. In recent years, when the 'magnifying glass' afforded by DNA has been directed toward oribatid mites, cryptic species seem to appear everywhere (e.g., Schäffer et al 2019;Pfingstl et al 2021Pfingstl et al , 2022.…”