Manodactylus Moser, 1919

Clavijo-Bustos, Julián, Castro-Vargas, María I. & Neita Moreno, Jhon César, 2024, A second species of the genus Manodactylus Moser, 1919 (Coleoptera, Scarabaeidae, Melolonthinae, Macrodactylini) from the highlands of Colombia, Deutsche Entomologische Zeitschrift 71 (1), pp. 209-217 : 209-217

Genus Manodactylus Moser, 1919

Type species.

Manodactylus gaujoni Moser, 1919 (by monotypy, junior objective synonym of Manodactylus gaujoni ( Ohaus, 1909) , comb. nov.)

Diagnosis.

Color black, shiny; clypeus trapezoidal; clypeus and frons forming a subpentagonal area, surface with small, coarse, rounded punctures densely and irregularly distributed giving a rugose appearance; frons with a smooth raised narrow area extending from anterior angles to the vertex, and delimiting the subpentagonal area; eyes small, interocular distance more than six times the dorsal width of the eye; antennae with nine antennomeres; pronotum diamond shaped, strongly wider medially, wider than long, and borders with small, rounded punctures bearing setae of different length; limit between scutellar shield and mesoscutum not evident; elytral base wider than pronotal base; each elytron with five striae between suture and humeral callus, 10 in total, each with a regular row of small, rounded punctures; prosternum with two anterior, longitudinal sulci; metaventrite densely setose medially; femora subequal in length to their respective tibiae; tibiae shorter than their respective tarsi; tarsal claws bifid, and with an acute triangular tooth basally; protibia along the outer edge with two teeth distributed in the apical third; protibia gradually widening from base to apex but narrowing from the inner edge in the apical third, and lacking apical spur; abdomen with intersegmental membrane VII – VIII exposed; abdominal ventrites 2–5 densely setose medially, and ventrite 5 evidently longer than the others; pygidium vertical, strongly convex; phallobase cylindrical, around 2.5 times the length of parameres; parameres fused at the base, short, apically slightly downward curved and with apex rounded.

Taxonomic remarks.

Manodactylus is very similar to Chariodactylus and Macrodactylus , all three genera sharing the trapezoidal clypeus, antennae with nine antennomeres, pronotum strongly wider medially, mesoscutum – scutellar shield limit not evident, prosternum anteriorly with two longitudinal sulci, protibia with two teeth on the outer edge, absence of protibial spur, and internal area of metatarsomere 5 unarmed ( Fuhrmann and Vaz-de-Mello 2017). Manodactylus also shares with Macrodactylus the small eyes (interocular distance of more than five times the dorsal width of the eye), and with Chariodactylus the pronotum slightly wider than long and the protibia gradually widening from base to apex but narrowing from the inner edge in the apical third.

As suggested in a previous work, a cladistic analysis including these three genera is needed to confirm the validity of these taxa ( Fuhrmann and Vaz-de-Mello 2017). However, we prefer to retain each of these genera as valid until this taxonomic issue will be resolved, and propose the following characters to distinguish Manodactylus from the other two genera (some of these characters were mentioned by Fuhrmann and Vaz-de-Mello 2017): small eyes (Fig. 5 B, D ) (large eyes in Chariodactylus , interocular distance of less than 3.5 times the dorsal width of the eye), pronotum glabrous (Fig. 5 A, C ) (setose in Chariodactylus ) and wider than long (Fig. 5 A, C ) (longer than wide or as long as wide in Macrodactylus ), and protibia gradually widening from base to apex but narrowing from the inner edge in the apical third (Fig. 4 A ) (protibia widening near the base but narrowing from the inner edge around the middle of the length in Macrodactylus ).

We identified some other morphological features which are probably useful to distinguish Manodactylus from the other genera, but we were unable to check them in other genera and species from outside of Colombia. Males of both species of Manodactylus have the inner angle of the protibia slightly projected downward (Fig. 4 B ) (kind of similar to the ‘ polex’ of some Ochodaeidae species), which is not projected in Macrodactylus species from Colombia. Also, males of Manodactylus paramicola sp. nov. have two mesotibial spurs (Fig. 4 D ) and one metatibial spur (Fig. 4 E ), while males of the Colombian species of Macrodactylus only have two spurs in the apex of mesotibiae.

Figures

Figure 4. Manodactylus paramicola sp. nov., male holotype. A. Protibia in dorsal view; B. Detail of the downward projection of the inner angle of protibia; C. Apex of protibia; D. Apex of mesotibia; E, Apex of metatibia. Black arrows point to downward projection of the inner angle of protibia.

Figure 5. Manodactylus species. A, B. Macrodactylus gaujoni Ohaus, 1909, male neotype = Manodactylus gaujoni Moser, 1919, male lectotype; C, D. Manodactylus paramicola sp. nov., male holotype. A, C. Pronotum in dorsal view; B, D. Head in dorsal view.