Dendropaemon (D.) aenigmaticus Génier & Arnaud, 2016

François Génier & Patrick Arnaud, 2016, Dendropaemon Perty, 1830: taxonomy, systematics and phylogeny of the morphologically most derived phanaeine genus (Coleoptera: Scarabaeidae, Scarabaeinae, Phanaeini), Zootaxa 4099 (1) : 24-25

11. Dendropaemon (D.) aenigmaticus Génier & Arnaud , new species

( Figs. 11 , 54–55, 112, 157)

Type locality. PK 125, Route N2 (Cayenne-Saint-Georges-de-L’Oyapock), Guyane française.

Diagnosis. The two-segmented meso- and metatarsi of which the first segment is approximately 3 times as long as wide at apex, the completely glossy black body and the clypeal teeth lacking emargination laterally will place this species in the piceus complex. From closely related species it can be separated from D. angustulus , D. larseni , D. telephus by its lager body size and more robust shape and dorsoventrally compressed body; from D. flechtmanni and D. vazdemelloi by its much finer elytral striae 1–4; from D. ater by its flat posterior protibial surface and nearly semicircular clypeal edge. The more slender and gradually tapering toward apex meso and metatibia will separate it from D. piceus , from which it also differs by its only minutely punctate elytral striae.

Description. Male holotype ( Fig. 11 ). Body. Body moderately large, length 14.5 mm, maximum width 8.0 mm; body subrectangular in dorsal view; dorsum largely flat. Color. Dorsal surface black, glossy, lacking metallic sheen; ventrum black; pygidium black; legs black. Head. Clypeus narrowly arcuate, anterior portion slightly upturned; clypeal teeth triangular; clypeal median emargination v-shaped, clypeal edge lacking emargination on external side of each clypeal tooth, clypeal teeth ventral surface with a well-defined v-shaped carina, clypeal margin ill-defined, lacking sharp carina posteriorly, clypeal surface with transverse blunt rugulae; clypeogenal suture well-defined, bluntly carinate internally; genal surface simply punctate, with a long and acute transverse carina; clypeofrontal carina low, more than 6 times wider than high, straight in dorsal view, simply carinate, clypeofrontal carina apical edge slightly sinuous medially in frontal view; eyes small in dorsal view, interocular ratio 4.4. Pronotum. Pronotum transverse in dorsal view, pronotal width/length ratio 1.5; disc of pronotum minutely punctate throughout, with a fine ill-defined longitudinal sulcus on posterior half; pronotal anterior margin only slightly wider and flat lateral to eye; anterior portion with a broad and fine tectiform carina tuberculate medially; anterior angles surface simply punctate, similar to lateral margin along posterior edge of anterior margin; lateral fossae simply rounded, concave; lateral portions slightly explanate; pronotal basal fossae ill-defined, moderately concave; posterior margin well-defined, lacking crenulation and setae. Elytra. Elytra approximately as long as wide in dorsal view, elytral combined width/length ratio 1.1; elytral base lacking distinct margin, simply convex; elytral striae 1–4 fine on disc, finer and lacking minute carina laterally on apical declivity, evenly impressed throughout, elytral striae 5 atrophied, lacking fine carina on each side on disc, strial punctures minute, stria 1 well-defined apically, connecting to marginal stria; interstriae flat, minutely punctate throughout, surface glossy. Thoracic sterna. Proepisternal carina reduced, present along coxal insertion only; metasternal median lobe angularly produced anteromedially, ventral ridge well-defined, keel-shaped. Legs. Profemur posterior surface flat and glabrous internally, posterointernal margin rather thick, evenly developed, internal edge rather narrow, with a brush of long setae along anterointernal edge, remaining surface with irregular ill-defined punctures and glossy. Protibia with four teeth on lateral edge; internal basal angle lobate; anterior surface with long aligned row of setae internally, surface glossy or feebly microsculptured between punctures; posterior surface with some ill-defined irregular punctures externally to median carina, surface finely and irregularly microsculptured between punctures, with a single interrupted setal row along lateral teeth. Mesofemur angularly produced on anterointernal edge apically. Mesotibia rather slender, gradually widening toward apex in anterior view; anteroapical edge straight in anterior view, anteroapical row of setae complete; apicoanterior edge circularly indented internally; external edge carinate, sharp. Mesotarsus similar in shape to metatarsus, 2-segmented, first segment elongate, more than three times as long as wide at apex. Metafemur elongate, internal and lateral edges mostly parallel in ventral view, more than twice as long as wide, lacking distinct depressed area anterointernally before apex, apicoposterior edge unmodified, anterior surface with a well-defined sulcus on apical half. Metatibia rather slender, gradually widening toward apex in anterior view, anterior surface with distinct row of setae, surface glossy, metatibial posterior surface flat between longitudinal row of setae and lateral edge, with transverse microsculpture. Metatarsus 2-segmented ( Fig. 112 ), first segment elongate, more than three time as long as wide at apex, with anterointernal carina illdefined. Abdominal sternites. Sternites 3–6 longitudinally flat; sternites 4–6 with 1–3 unaligned rows of setae laterally, glabrous medially; sternite 7 approximately longitudinally flat medially, shorter than segment 6 along midline; pygidium minutely punctate on disc. Male genitalia (Figs. 54–55). Parameres simply rounded apically in dorsal view; surface smooth, glossy apically.

Measurements (1 male). Length: 14.5 mm.

Primary type data. Holotype male (CPFA): [24/12/2007 PI/ rt st georges PK125/ JL GIUGLARIS]; WORLD/ SCARAB./ DATABASE/ WSD00017631]; [HOLOTYPE / Dendropaemon / aenigmaticus n.sp. / Génier & Arnaud, 2014] red card.

Material examined. Primary type only.

Etymology. Aenigmaticus , an adjective relating to the status of this species known only by the holotype despite extensive collecting in French Guiana using flight interception traps.

Natural history. Unknown.

Remarks. Female and variation unknown.

At the moment we feel confident that this individual represents a new species, especially as the sclerites of the internal sac also differs from D. ater , its most closely related species.

Figures

FIGURES 7 – 12. Dorsal habitus. 7. D. inflatus, female holotype; 8. D. pauliani, female holotype; 9. D. pilosissimus, female holotype; 10. D. renatii, female holotype; 11. D. aenigmaticus, male holotype; 12. D. amazonicus, male holotype.

FIGURES 110 – 117. Metatarsus, ventral view. 110. D. bluti; 111. D. carinifer; 112. D. aenigmaticus; 113. D. amazonicus; 114. D. angustulus; 115. D. viridis; 116. D. viridipennis; 117. D. convexus.