Endotribelos

Epler, John H., 2017, AN ANNOTATED PRELIMINARY LIST OF THE CHIRONOMIDAE (DIPTERA) OF ZURQUÍ, COSTA RICA Abstract Introduction, CHIRONOMUS Journal of Chironomidae Research 30 (30), pp. 4-18 : 10

Endotribelos

- Two described species and one undescribed species were collected. Fourteen specimens of E. albatum and 40 (including two intersex specimens) of E. grodhausi were examined; seven specimens of the undescribed species were collected. The undescribed species has a long thin anal point and appears similar to, but lighter than, an undescribed species from La Selva, of which I have several reared associations.

Endotribelos was established by Grodhaus (1987) for Tendipes (Tribelos) hesperia Sublette, 1960 (which thus became Endotribelos hesperium (Sublette)) , a southern US species whose larva has an odd number of teeth on the mentum and a large gap (diastema) between the molar area and the proximal inner tooth of the mandible. Subsequently, Sublette & Sasa (1994) described two species from Guatemala, E. albatum and E. grodhausi ; the larva of E. grodhausi has an even number of mental teeth and lacks the mandibular diastema (the larva of E. albatum remains unknown). Since then, several more species have been described from South America ( Roque & Trivinho-Strixino 2008 and Trivinho-Strixino & Pepenelli 2015), the larvae of which display a variety of those character states. See also Epler et al. (2013).

Trivinho-Strixino & Pepenelli (2015) provided keys for the males and known larvae of Endotribelos . However, male E. grodhausi will not key correctly because couplet 4 gives one the choice of “base of superior volsella setose” or “base of superior volsella bare”. Choosing “bare” eventually leads to E. grodhausi at couplet 14. However, the base of the superior volsella of E. grodhausi is clothed, ventrally and dorsally, with fine setae. Thus, E. grodhausi will key to E. jaragua Trivinho-Strixino & Pepenelli in couplet 5, from which it may be separated by the darker thorax of E. grodhausi (preepisternum and adjacent sclerites are dark; light in E. jaragua ). Sasa and Sublette’s illustration of the volsella ( Sublette & Sasa 1994: fig. 141) does not indicate the presence of setae, which apparently led Trivinho-Strixino & Pepenelli (2015) to assume the structure was bare. Sublette & Sasa (1994: fig. 135) likewise illustrated the base of the superior volsella of E. albatum as bare, when it also is clothed with fine setae. I examined two paratypes of E. albatum and eight paratypes of E. grodhausi .