Dactylobasis, Pérez-Gutiérrez, 2019

Pérez-Gutiérrez, León Andrés, 2019, Dactylobasis gen. nov. from Colombia, a new genus of Zygoptera with Teinobasini affinities (Odonata: Coenagrionidae), Zootaxa 4656 (2), pp. 232-242 : 234

Dactylobasis gen. nov.

( Figs 2–6 )

Type species Dactylobasis demarmelsi sp. nov. by original designation.

Etymology. Daktylos (Greek): finger; the genus name refers to the articulated, digitiform ventral spur at base of cercus.

Description. Head. Medium sized coenagrionid with angulate frons, deeply sunk between bases of antennae; occipital rim prolonged laterally into an anteriorly curved carina, postocular lobe not surpassing compound eye posteriorly; postocular spot and pale mark between lateral ocellus and base of corresponding antenna absent.

Thorax. Propleuron with distally directed, spinulose conical projection. Mesanepisternum entirely metallic green, each with a long horn, in both sexes. Legs short, metatibial spines slightly shorter than intervals separating them, supplementary teeth of tarsal claws reduced to low swelling.

Caudal appendages. Male cercus short and cap-like in lateral view, and with ventral spur articulated at membranous base; paraproct long with short ventral branch at half of its length.

Generic diagnosis. Dactylobasis is considered to be a member of Teinobasini based on the presence of an articulated ventro-basal spur on male cercus shared with Aceratobasis , Bromeliagrion , Chromagrion , Diceratobasis , Nehalennia and Tepuibasis . A movable spur is absent in the Ceriagrion-Telebasis - Metaleptobasis series ( Kennedy 1920). Schistolobos and some Aceratobasis also have a ventro-basal branch ( von Ellenrieder & Garrison 2008), but it is not movable nor articulated. Dactylobasis differs from other genera of neotropical Teinobasini by the completely metallic green mesanepisternum, and the unusual development of propleuron bearing a posteriorly directed conical projection with spinulose texture (however, there is a similar structure in the propleuron of several species of Metaleptobasis ; von Ellenrieder 2013). Chitinized spinules on genital ligula, like those present in Aceratobasis , Bromeliagrion and Tepuibasis are absent in Dactylobasis . In Tepuibasis and Nehalennia the inner fold is well developed, but absent in Dactylobasis as well as in Diceratobasis . In addition, Dactylobasis has very long and bifurcate paraproct that contrasts with the very short cap-like cercus. Absence of a vulvar spine on female S8 is shared with Aceratobasis and Diceratobasis .

Based on the vein descending from quadrangle in hind wing forming a straight line to wing margin and dorsum of head entirely black, Dactylobasis keys out to couplets 59 and 78 in the keys to males and females of Coenagrionidae genera in Garrison et al. (2010) respectively. These keys can be modified as follows to include Dactylobasis :

Figures

FIGURE 2. Dactylobasis demarmelsi sp. nov. (a–b) male head and prothorax, lateral view; (b) female head, dorsal view; (c) thorax showing left projection of propleuron, lateral view; (d) thoracic color pattern; (e) male prothorax, dorsal view showing projections of propleuron (f) male thorax, dorsal view. Pp: Propleuron projections.

FIGURE 3. Dactylobasis demarmelsi sp. nov. (a) male S10, lateral view; (b) cercus, dorsal view; (c) male S10 posterior view; (d) male cercus and paraproct, left lateral view; (e) male, cercus inner view; (f) male S10, ventral view; (g) female S8–10, lateral view. vs: ventral articulated spur.

FIGURE 4. Dactylobasis demarmelsi sp. nov. (a) fore and hind left wings of male; (b) fore and hind left wings of female; (c) genital ligula, ectal view; (d) latero ental view; (e) lateral view.

FIGURE 5. Dactylobasis demarmelsi sp. nov., male at Quibdó, Salero, Chocó, Colombia. Unión Panamericana (5° 22’00.17’’ N 76° 36’03.11’’W) (Chocó, Colombia), 28 January 2013. Photo by LP.

FIGURE 6. Dactylobasis demarmelsi sp. nov., female at Salero, Unión Panamericana, Chocó, Colombia. (5° 22’00.17’’N 76° 36’03.11’’ W) (Chocó, Colombia), 28 January 2013. Photo by LP.