Luispenaia Martínez, 1972

Mondaca, José, Pizarro-Araya, Jaime & Alfaro, Fermín M., 2019, Revision of the genus Luispenaia Martínez (Coleoptera: Scarabaeidae: Melolonthinae: Tanyproctini), with description of three new species from the Atacama Desert, Chile, Zootaxa 4615 (3), pp. 549-562 : 550-551

Genus Luispenaia Martínez, 1972

( Figs. 1–7 , 9–29 )

Luispenaia Martínez, 1972: 86 . (original description); Martínez 1975: 247 (catalog); Evans 2003: 219. (checklist); Lacroix 2007: 380. (catalog); Evans & Smith 2009: 187 (checklist).

Type species. Luispenaia paradoxa Martínez, 1972 , by original designation.

Diagnosis. Length 4.8–8.0 mm; body subcylindrical elongate; color light brown to black; dorsal, lateral, and ventral surface abundantly setose ( Figs. 9 , 18, 21, 24, 27 ). Labrum and mandibles reduced ( Figs. 2–3 ). Labium long and narrow, anteriorly projected in an apophysis densely setose ( Fig. 3 ), variable in length and wide, subacute, rounded or truncate distally, with labial palpus reduced. Maxillary palpus large; palpus 1 short, palpus 2 longer than 3. Maxillary palpus 4 large, fusiform, shorter or subequal than 1–3 combined, distally attenuate and finished in a sensory pore. Clypeus well developed, subquadrate or rounded, with margins reflexed upturned, concave in spoon- like fashion ( Figs. 10–13 ). Frontoclypeal suture distinctly impressed. Eyes small to large, spheroidal, with eyes canthus subcuneiform or linguiform; basolaterally covered by the posterior prolongation of the clypeal margin ( Figs. 10–13 ). Antennae large, with 8 or 9 antennomeres, antennal club with 3–6 lamellate antennomeres short or considerably long ( Figs. 14–17 ). Pronotum wider than long, convex, approximately subovate, subtrapezoidal or subhexagonal, widest medially and strait in the anterior half, laterally surrounded with abundant long setae; anterior margin concave, with membrane; anterior angles not protruding, anterolateral margins straight or slightly rounded; lateral margins arched, posterior margin straight or slightly rounded; posterior angles obtuse; surface coarsely, almost regularly punctate ( Figs. 10–13 ). Elytra slightly convex or flattened, subparallel, with striae distinctly impressed, slightly widened in the posterior third, with apex rounded; humeral tubercle prominent. Hind wing fully developed, functional ( Fig. 4 ). Venter with 3 ventrites exposed medially, penultimate ventrite membranous on posterior margin ( Fig. 6 ). Pygidium with apex rounded, margins slightly reflexed, recumbent toward metacoxae. Protibiae long, tridentate, protibial spur slightly curved. Mesotibiae and metatibiae slender, widened medial and apically, with one oblique spinose carina externally, apical edge of the mesotibiae with row of long equal macrosetae, metatibiae with row of very small equal macrosetae barely perceptible; mesotibia with 2 spurs subcontiguous; metatibia with 2 spurs, one located adjacent to tarsal articulation and the other set on a different plane within apical tibial notch. Metatibia with two notable processes at the base of the foramen of the tarsal insertion. Mesotarsus and metatarsus thin, longer than metatibia. Protarsomeres, mesotarsomeres, and metatarsomeres 1–3 subequal in length; tarsomere 4 slightly shorter than the previous tarsomeres; tarsomere 5 longer than 1–4 individually; all tarsi with long, apical setae. All tarsal claws symmetrical, straight, and thin, medially and ventrally cleft, slightly curved and acute at apex ( Fig. 5 ). Aedeagus with parameres symmetrical, long, and slender.

Distribution and habitat. This genus actually is endemic to the Atacama Desert ( Fig. 8 ). Species of Luispenaia inhabit arid and semiarid environments of northern Chile ( Figs. 30 A–D), from near sea level (43 m) in the coast of the Paposo Norte Natural Monument (Antofagasta Region) to middle elevation (1000 m) in the mountains located to south of Copiapó (Atacama Region) and near of Coquimbo and Lagunillas (Coquimbo Region). Species occur in the Paramo Punan subregion (Atacama Province) and Central Chilean subregion (Coquimbo Province) as defined by Morrone (2014).

Natural history. Little is so far known of the ecology and natural history of Luispenaia species. Adults are diurnal, crepuscular, or nocturnal. Specimens of these small scarabs have been collected in large numbers at lights at night during the spring of a year that had a very rainy winter (ENSO event), also in pitfall traps, on foliage of Adesmia sp. ( Fabaceae ) and buried under stones. Species of this genus occur in xerophytic habitats in northern Chile ( Figs. 30 A–D).

Females are unknown, probably no flight, underground, brachypterous or apterous as many Tanyproctini taxa, consequently rarely observed and are very different to the habitus from males.

Tribal placement. Luispenaia were placed in Tanyproctini (at the time, Pachydemini ) by previous authors ( Martínez 1972, 1975; Evans 2003; Lacroix 2007; Evans & Smith 2009), and this tribal-level classification has been maintained since the last Pachydemini (now Tanyproctini ) world catalog prepared by Lacroix (2007). Luispenaia species were placed in Tanyproctini because the labrum is reduced, not visible in dorsal view of head ( Fig. 2 ); pygidium large, subtriangular, covered by elytral apex; tarsal claws cleft ventrally at proximal half ( Fig. 5 ); metatibia with 2 spurs, one located adjacent to tarsal articulation and the other set on a different plane within apical tibial notch ( Fig. 7 ); sternites distinctly defined (not fused), basal sternites compressed lengthwise; apex of abdomen recumbent toward metacoxae ( Fig. 6 ). Based on this morphological characters mentioned earlier, we think that Luispenaia genus it must be maintained in this tribe until morphological and molecular studies are carried out that support or disprove the tribal position that currently occupies.

Figures

FIGURE 8. Distribution of Luispenaia species in the Atacama Desert, northern Chile.

FIGURE 9. Male holotype of Luispenaia paradoxa Martínez. Scale: 1 mm.

FIGURES 10–13. Head and pronotum of Luispenaia species. 10, Luispenaia atacamensis; 11, L. paposo; 12, L. paulseni; 13, L. paradoxa. Scale: 0.5 mm.

FIGURES 14–17. Antennal club of Luispenaia species. 14, Luispenaia paradoxa Martínez; 15, L. paposo; 16, L. paulseni; 17, L. atacamensis. Scale: 0.5 mm.

FIGURES 18–29. Luispenaia species. 18–20, Luispenaia atacamensis; 21–23, L. paposo; 24–26, L. paulseni; 27–29, L. paradoxa. Scale: 1 mm.

FIGURES 30. Type locality of Luispenaia species. A, Llanos de Challe National Park (Atacama Region, Chile), habitat of L. paradoxa; B, Boqueron Chañar (Atacama Region, Chile), habitat of L. atacamensis; C, Paposo Norte Natural Monument (Antofagasta Region, Chile), habitat of L. paposo; D, Quebrada Los Yales (Antofagasta Region, Chile), habitat of L. paulseni.

FIGURE 1–7. Generic characters of the genus Luispenaia. 1, head and antennal club; 2, eyes and mouth part in ventral view; 3, eyes and mouth part in lateral view; 4, right wing; 5, pretarsal claw; 6, abdomen in ventral view; 7, metatibial apex in frontolateral view. Scale: 0.5 mm (Figs. 1–3); 1 mm (Figs. 4, 6); 0.25 mm (Fig. 5); 0.5 mm (Figs. 5, 7).