Rhodnius micki, a new species of Triatominae (Hemiptera, Reduviidae) from Bolivia

Abstract

Rhodnius Stål, 1859 is the second largest genus of Triatominae after Triatoma Laporte, 1832, and includes several important Chagas vectors. Genitalia in Reduviidae are frequently used for species identification, but the current use of terminology for it is inconsistent in Triatominae. Here, Rhodnius micki sp. nov., is described from Bolivia and considered as belonging to the pictipes group based on its morphological characters and distribution. Detailed documentation of the genitalia of Rhodnius micki sp. nov. is provided with emphasis on its everted phallus, especially the endosomal sclerites, which are potentially useful as species-level diagnostic features in Rhodnius. To further verify the validity of this species, the head shapes and wing venation patterns of five species in Rhodnius are compared with morphometric analysis. After reviewing taxonomic and comparative morphology papers of assassin bugs, a vocabulary with a terminology of morphological characters, especially of external male genitalic characters, is assembled with the preferred terms and the synonyms listed. Establishing a consistent terminological framework will greatly facilitate future research on the homology of these structures across Triatominae and will ultimately contribute to our understanding of the evolution of these groups.

Keywords: Comparative terminology; genitalia; geometric morphology; kissing bug; taxonomy.

Figures 1–6.

Process of dissection 1 soaking genitalia in 100% lactic acid overnight 2 boiling genitalia in 20% lactic acid solution for ~ 30 minutes 3–6 dissecting genitalia under microscope with forceps and blunted insect pin 4, 5 inserting the insect pin along the membrane of the endosoma and agitate the pin 6 using forceps to stretch the endosoma.

Figures 7–11.

7–9 holotype of Rhodnius micki sp. nov. 11Rhodnius stali Lent, Jurberg & Galvão, 1993 7 dorsal side 8 lateral side 9 ventral side 10, 11 pronotum. Scale bars: 5.00 mm (7–9); 1.00 mm (10, 11)

Figures 12–16.

Pygophore and paramere of paratype of Rhodnius micki sp. nov. 12–14 pygophore 12 dorsal view 13 lateral view 14 ventral view 15, 16 paramere: 15 dorsal view 16 lateral view. Scale bars: 1.00 mm. Abbreviations: DSPr dorsal sclerites of pygophore MPPy Median process of pygophore TBPy Transverse bridge of pygophore.

Figures 17–26.

Pallus 17–24Rhodnius micki sp. nov. 25, 26Rhodnius robustus17–19 non-everted phallus 20–26 everted phallus 17, 20 dorsal side 18, 21 lateral side 19, 22 ventral side 23, 25 distal ventral sclerite of endosoma 24, 26 distal dorsal sclerite of endosoma. Scale bars: 1.00 mm (11–16); 0.50 mm (17–20). Abbreviations: BP basal plate TBBP transverse bridge of basal plate DPS dorsal phallothecal sclerite MBSPh medial basal sclerite of phallosoma LFPPh lateral flat-like prolongation of phallosoma VSPh ventral sclerite of phallosoma BPE basal plate extension DDSEn distal dorsal sclerite of endosoma DVSEn distal ventral sclerite of the endosoma AA articulatory apparatus Ph phallosoma En endosoma.

Figures 27, 28.

Morphological variations of five Rhodnius species based on Principal Component Analysis. The 90% equal frequency ellipses containing approximately 90% of the data points are shown. The thin-plate splines show the average shape for each species, corresponding to the deformation of the landmarks compared with the origin (the average shape of all species) 27 head 28 fore wing.