Macrodactylus miguelangeli Arce-Pérez, 2021

Arce-Pérez, Roberto & Reynoso-Velasco, Daniel, 2021, Two new species of Macrodactylus (Coleoptera: Scarabaeidae: Melolonthinae Macrodactylini) from Mexico and Guatemala, Zootaxa 4903 (4), pp. 493-500 : 494-497

Macrodactylus miguelangeli Arce-Pérez , new species

(Figs. 1–2, 5–8, 17)

Type series. HOLOTYPE ³. GUATEMALA: Quetzaltenango, El Palmar , 14°39’N, 91°35’W, 1000 m, 16.IV.1994, M. Goyzueta ( IEXA) . ALLOTYPE: same data as holotype (1♀ IEXA) . PARATYPES (4³, 7♀): same data as holotype (1³, 2♀ IEXA) ; Quetzaltenango, Coatepeque , 500 m, 18.IV.1956, D.H. Janzen (1♀ EMEC) ; Suchitepequez, Mazatenango , 16.IV.1956 (1³, 2♀ CMNC) . MEXICO: Chiapas, Escuintla, Reserva Cordón Paxtal, Nueva Morelia , 2000 m, 12. VI.2001, E. Galdámez (1³, 1♀ IEXA; 1³, 1♀ MXAL) .

Diagnosis. Integument of the body reddish yellow; pronotum, elytra, and pygidium covered with pale-yellow vestiture; elytra with three broad, longitudinal bands of setae; tarsi without rings of setae (Figs. 1–2); protibia with a well-developed keel basally (not visible in the figures); pygidial plate yellowish red (Fig. 2); parameres oval, glabrous, with lanceolate apex (Figs. 5–6).

Figures 5–8. Genital structures of the male and female of Macrodactylus miguelangeli new species. 5, Male parameres, posterior view (arrow indicates keel); 6, male parameres, lateral view; 7, male phallobase, dorsal view; 8, female genital plates, posterior view. Scale bars in 5–6 = 0.44 mm, 7 = 1 mm, and 8 = 0.43 mm.

Description. Holotype. Male: Body length 11.00 mm; humeral width 3.50 mm. Color: body reddish yellow; clypeus, antennae, elytra, legs, and pygidium darker; head and pronotum dark red; pterothorax, abdomen, apex of tibiae, and tarsi dark (Figs. 1–2). Surface: head and pronotum with scattered yellow setae not completely covering the integument; elytra with three broad, longitudinal bands of setae; ventrally with long yellow vestiture; pygidium with scattered vestiture, similar to that of the venter (Fig. 2). Head: elongate; clypeus trapezoidal, dark red, punctate, with anterior border straight. Thorax: pronotum hexagonal, convex, length 2.80 mm, width 2.70 mm; prosternal process long, flattened, apex rounded (easily visible in frontal view); scutellum subtriangular; elytra with three well-defined longitudinal bands of pale-yellow setae on interstriae 1, 3, and 5; bands 1 and 5 slightly converging posteriorly, band 3 short and broad, and one faint sublateral row of setae (Fig. 1); interstriae 2 and 4 not raised (not costate). Metasternum broad, with two longitudinal rows of spine-like setae between the mesocoxae and metacoxae. Legs: profemur with a subrectangular projection near the base; ventral surface of protibia with a well-developed, convex keel in basal half; mesotibiae widened toward the apex, with two long, straight, acute spurs; tarsi without rings of white setae; all tarsal claws cleft. Abdomen: robust, sternites 2–5 moderately concave (lateral view), with two or three spine-like, slender setae on each side of midline; pygidial plate elongate, oval, convex, with long setae apically. Genitalia: total length 3.05 mm (Fig. 7); parameres length 1.32 mm, width 0.96 mm, stout, oval (posterior view), glabrous, completely fused dorsobasally, with a short, transversal keel above junction, each apex strongly lanceolate (Figs. 5–6).

Allotype female: Similar to male except for: body length 10.50 mm; humeral width 3.48 mm. Pronotum length 2.60 mm, width 2.80 mm; abdominal sternites convex (lateral view), with slender, scattered, reddish-yellow setae along midline; pygidium short, subtriangular. Genital plates large, nearly subtriangular, length 1.30 mm, width 0.50 mm, lateral margin slightly expanded basally (Fig. 8).

Variation: Body length 10.50–11.00 mm; humeral width 3.00–3.50; ventrally intense dark red; elytra with fine vestiture; prosternal process small and not conspicuous.

Geographical distribution. This species is distributed in the southern Mexican state of Chiapas and the southwestern Guatemalan departments of Quetzaltenango and Suchitepequez (Fig. 17). The localities in both countries are in the Chiapas Highlands biogeographic province. This new species is part of the group of species of Macrodactylus distributed in the Central American Nucleus (see Arce-Pérez & Morón 2020). The number of species of this genus distributed in the area reaches 21.

Natural history. This species inhabits a tropical rain forest at elevations of 500–2000 m and was collected during April and June.

Etymology. This species is dedicated to the memory of Dr. Miguel Ángel Morón Ríos, who was a mentor of R.A.P. and contributed extensively to the knowledge of Neotropical scarab beetles.

Comments: Macrodactylus miguelangeli is included in the M. lineatus species group (sensu Arce-Pérez & Morón 2000) because it has the clypeus with the anterior margin nearly straight; the metasternum with irregular, longitudinal rows with few short setae between the mesocoxae and metacoxae; the mesotibia has two long, narrow, straight, and acute spurs; the tarsi do not have rings of setae; and the parameres are oval and glabrous. In the work of Arce-Pérez & Morón (2000), 13 specimens from Mexico and Guatemala were identified (only based on the original description) and reported as M. costulatus Bates, 1887 . Of those, the six specimens from Guatemala (Quetzaltenango) exhibited some superficial differences that at the time were considered as geographical variation. After reviewing approximately 500 specimens of M. costulatus from Costa Rica, El Salvador, Guatemala, Honduras, and Mexico reported in previous works ( Arce-Pérez & Morón 2005, 2018, 2020), R.A.P found that the specimens from Guatemala reported by Arce-Pérez & Morón (2000) as M. costulatus , as well as three specimens from Guatemala (Suchitepequez) and four specimens from Mexico (Chiapas) not previously reported, presented specific characteristics that distinguished them as a distinct species, herein described as M. miguelangeli . At least five characters are useful in order to distinguish this new species from its closest congener: elytra with three well-defined longitudinal bands of setae (Fig. 1) [only two in M. costulatus (Fig. 3)], interstriae 2 and 4 not raised (raised in M. costulatus ), pygidial plate yellowish red (Fig. 2) [generally black in M. costulatus (Fig. 4)], and parameres with a short, transversal keel above junction (Fig. 5) (without keel in M. costulatus ) and apical half of lateral margins straight (Fig. 5) (slightly concave in M. costulatus ).

Figures 9–12. Dorsal and lateral habitus of species of Macrodactylus . 9–10, Male holotype of Macrodactylus oaxacaensis new species; 11–12, M. montanus Arce-Pérez & Morón, 2000 . Scale bars in 9–10 = 5.0 mm.