The Waterston’s evaporatorium of Ceraphronidae (Ceraphronoidea, Hymenoptera): A morphological barcode to a cryptic taxon

Abstract

The Waterston’s evaporatorium (=Waterston’s organ), a cuticular modification surrounding the opening of an exocrine gland located on metasomal tergite 6, is characterized and examined for taxonomic significance within the parasitoid wasp family Ceraphronidae. Modification of the abdominal musculature and the dorsal vessel are also broadly discussed for the superfamily Ceraphronoidea, with a novel abdominal pulsatory organ for Apocrita being discovered and described for the first time. Cuticular modification of T6, due to the presence of the Waterston’s evaporatorium, provides a character complex that allows for genus- and species-level delimitation in Ceraphronidae. The matching of males and females of a species using morphology, a long standing challenge for the group, is also resolved with this new character set. Phylogenetic analysis including 19 Waterston’s evaporatorium related characters provides support for current generic groupings within the Ceraphronidae and elaborates on previously suggested synapomorphies. Potential function of the Waterston’s organ and its effects on the dorsal vessel are discussed.

Surprising morphological diversity in ceraphronid wasps revealed by a distinctive new species of Aphanogmus (Hymenoptera: Ceraphronoidea)

“…Recently, the Waterston's evaporatorium on the 6 th metasomal tergite was discovered to be a taxonomically significant character complex in Ceraphronidae (Ulmer et al 2021). Major differences in the structure of the Waterston's evaporatoria of Aphanogmus and Ceraphron Jurine, 1807 were found and are supported by a cladistic analysis, which returned a monophyletic Aphanogmus group and a paraphyletic Ceraphron group (Ulmer et al 2021). Apart from Aphanogmus s.…”

“…nov. lacks campaniform sensilla on T5 and T6 (Fig. 2D), a character that is considered an autapomorphy of Elysoceraphron by Ulmer et al (2021). However, there are several differences in external morphology that contradict the placement of the newly described species into Elysoceraphron: (1) the mesoscutellum of A. kretschmanni is rounded posteriorly rather than subrectangular, which is the diagnostic character for Elysoceraphron; (2) the head of A. kretschmanni is significantly more transverse, a character shared by most species of Aphanogmus, than that of the Palearctic E. hungaricus Szelényi, 1936 or of the Oriental E. aadi Bijoy & Rajmohana, 2021 with the interocular distance being larger than the eye width (A. kretschmanni: 158:146 µm; E. hungaricus: 152:228 µm; E. aadi: 146:222 µm); (3) the anteromedian projection of the metanoto-propodeo-metapectomesopectal complex is straight in A. kretschmanni whereas it is upcurved in Elysoceraphron.…”

“…The morphological terminology in this study used mainly for the description in natural language as well as the machine-readable description in Supp. file 1 follows that of the Hymenoptera anatomy ontology (Yoder et al 2010) and Mikó & Deans (2009) with some additional terms on ovipositor morphology from Ernst et al (2013) and the Waterston's evaporatorium from Ulmer et al (2021).…”

Deep learning for identifying bee species from images of wings and pinned specimens

“…In this case, wing scanning may be faster than morphometrics and cheaper than DNA barcoding for attaining bee identifications, especially for ecologists with less experience in subtle morphometric differences. Essentially, such scans may serve as time efficient and reliable morphological barcode ( sensu 32 ).…”

Mission possible: an optimised protocol for the unbarcodable Ceraphronoidea (Hymenoptera)

“…External morphology alone is not sufficient to diagnose species as characters tend to be monotonous throughout the superfamily and often affected by allometry. The two taxonomically useful morphological characteristics of this group are the male genitalia ( Mikó et al 2013 ) and the Waterston’s evaporatorium ( Ulmer et al 2021 ). While effective in species delimitation, these two character complexes have their limits, the first one being confined to one sex and the latter referring to just one of the two families - Ceraphronidae .…”