Dendropaemon (D.) angustulus 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) : 26-28

13. Dendropaemon (D.) angustulus Génier & Arnaud , new species

( Figs. 13 , 58–59, 114, 157)

Type locality. 26 km N Guasipati, Bolivar, Venezuela.

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 most other species in the group by its smaller size and robust metafemur which is approximately twice as long as wide. From D. telephu s by its narrower elytral striae and from D. larseni by its smaller size and geographic distribution (see remarks below).

Description. Male holotype ( Fig. 13 ). Body. Body small, length 11.0 mm, maximum width 5.0 mm; body subrectangular in dorsal view; dorsum slightly convex. Color. Dorsal surface black, glossy, lacking metallic sheen; ventrum black; pygidium black; legs black. Head. Clypeus broadly 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 fine 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 sharp transverse carina; clypeofrontal carina low, more than 6 times wider than high, straight in dorsal view, simply carinate, clypeofrontal carina apical edge straight in frontal view; eyes small in dorsal view, interocular ratio 4.0. Pronotum. Pronotum transverse in dorsal view, pronotal width/length ratio 1.4; disc of pronotum finely punctate basally, punctures becoming larger anteriorly, with a fine longitudinal sulcus on posterior half; pronotal anterior margin wider and flat lateral to eyes; anterior portion with a slightly tri-sinuous carina; 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 very small and rounded; posterior margin ill-defined, lacking setae. Elytra. Elytra approximately as long as wide in dorsal view, elytral combined width/length ratio 1.0; elytral base lacking distinct margin, simply convex; elytral striae 1–4 moderately wide 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 ill-defined throughout, stria 1 well-defined apically, connecting to marginal stria; interstriae slightly convex, minutely punctate throughout, surface glossy. Thoracic sterna. Proepisternal carina absent; metasternal median lobe angularly produced anteromedially, ventral ridge absent. Legs. Profemur posterior surface slightly but distinctly convex and glabrous internally, posterointernal margin rather thin, evenly developed, internal edge rather narrow, with a brush of long setae along anterointernal edge, remaining surface smooth along setae. 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 between punctures finely and irregularly microsculptured, with a single interrupted setal row along lateral teeth. Mesofemur angularly produced on anterointernal edge apically. Mesotibia rather short, 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 more or less rounded, with several large elongate setiferous punctures. Mesotarsus similar in shape to metatarsus, 2-segmented, first segment elongate, more than three times as long as wide at apex. Metafemur internal edge nearly straight and lateral edge arcuate, lacking distinct depressed area anterointernally before apex, apicoposterior edge unmodified, anterior surface with a well-defined sulcus on more than half the length. 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. 114 ), first segment elongate, more than three time as long as wide at apex, with anterointernal carina ill-defined. 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 finely punctate on disc. Male genitalia (Figs. 58–59). Parameres simply rounded apically in dorsal view; with minute raspy tubercles apically.

Measurements (14 males, 29 females). Length: male 8.5–11.5 (9.8±1.0), female 7.5–11.5 (9.6±1.0) mm.

Primary type data. Holotype male (CMNC): [VEN: BOLIVAR/ 26km N Guasipati/ 24.VI.–12.VII.87 / S&J Peck, FIT, sandy/ seasonlyhumidforest]; [WORLD/ SCARAB./ DATABASE/ WSD00017021]; [HOLOTYPE / Dendropaemon / angustulus n.sp. / Génier & Arnaud, 2014] red card.

Material examined. BRAZIL: AMAZONAS, Reserva Florestal Adolpho Ducke, 26 km NE Manaus, (2°57'S, 59°57'W), 1995–1996, coll. [anonymous]— 2 males (incl. 2 paratypes) ( BMNH); PARÁ, Estação de pesquisas Pinkaití, Area Indigena Kayapo, Redenção, (7°46'S, 51°58'W), x.1999, coll. P. Y. Scheffler— 1 female, 1 male (paratypes) ( CEMT); Municipio Redenção, (7°46'S, 51°58'W), xii.1998, coll. P. & T. Scheffler— 1 female (paratype) ( CEMT); same locality, xi.1998, coll. P. & T. Scheffler— 1 male (paratype) ( CEMT); Óbidos, (1°54'30''S, 55°31'8''W), [no date], coll. [anonymous]— 1 female (paratype) ( SMF); same locality, xi.1953, coll. F.M. Oliveira— 1 male (paratype) ( WDEC); RORAIMA, Ilha de Maracá, (3°25'N, 61°40'W), ix.1996, coll. Ribeiro & Vaz-de-Mello— 1 female (paratype) ( CEMT); GUYANA: UPPER DEMERARA-BERBICE, Kurupakari, Rio Essequibo, (4°40'N, 58°40'W), viii.1920, coll. A.A. Abraham— 1 female (paratype) ( BMNH); GUYANE FRANÇAISE: Crique Blanche, R.N. 2, (4°33'39''N, 52°23'50''W), v.2011, coll. Giuglaris— 1 female, 1 male (paratypes) ( CPFA); Régina, (4°19'N, 52°8'W), viii.2009, coll. F. Bondil— 1 female (paratype) ( CEMT); same locality, i.2009, coll. [anonymous]— 1 female, 1 male (paratypes) ( CPFA); Réserve naturelle des Nouragues, (4°19'N, 52°22'W), ii.2003, coll. F. Feer— 2 females (incl. 2 paratypes) ( MNHNB); same locality, 28.iv.2001, coll. F. Feer— 1 female (paratype) ( CPFA); same locality, 28.iii.2002, coll. F. Feer— 2 females (incl. 2 paratypes) ( CPFA); same locality, 25.vi.2008, coll. F. Feer— 1 female (paratype) ( MNHNB); same locality, 26.viii.2010, coll. [anonymous]— 1 female, 1 male (paratypes) ( COBF); Saül, (3°37'N, 53°12'W), 20.v.2011, coll. [anonymous]— 1 female (paratype) ( COBF); same locality, 27.v.2011, coll. [anonymous]— 1 female (paratype) ( COBF); VENEZUELA: BOLIVAR, 26 km N Guasipati, (7°41'35''N, 61°57'19''W), 24.vi.–12.vii.1987, coll. S. & J. Peck— 2 females, 4 males (incl. holotype, 4 paratypes) ( BDGC, CMNC); 8 km N Guri, elev. 200 m (7°48'49''N, 63°0'52''W), 16.vii.–11.viii.1986, coll. B. Gill— 1 female (paratype) ( BDGC); Guri, (7°46'16''N, 63°1'42''W), 15– 17.vi.1996, coll. H. & A. Howden— 1 female (paratype) ( CMNC); Lago Guri Islands, elev. 270 m (7°21'N, 62°52'W), v–vi.2003, coll. T. Larsen— 1 male (paratype) ( AFIC); Puente Cocuizas, 70 km Ciudad Bolivar, (7°41'35''N, 64°0'18''W), 19.vi.–3.viii.1987, coll. S. & J. Peck— 2 females, 1 male (paratypes) ( BDGC, CMNC); Río Caura, 10 km N Corocito, (7°8'40''N, 64°58'28''W), 18.vi.–3.viii.1987, coll. S. & J. Peck— 2 females (incl. 2 paratypes) ( BDGC, CMNC); Río Caura, near Puerto Cabello del Caura, (7°8'N, 64°59'W), 15–28.xii.1987, coll. B.D. Gill— 1 female (paratype) ( BDGC); Río Sipao, 110 km E Caicara, (7°24'47''N, 65°12'24''W), 17.vi.– 4.viii.1987, coll. S. & J. Peck— 3 females (incl. 3 paratypes) ( BDGC, CMNC).

Etymology. Angustulus , a Latin adjective related to the narrow body of this species.

Natural history. All specimen with data on collecting method were obtained using flight interception traps set in dry forest, forested ravine in woodland, gallery forest, rainforest and sandy seasonally humid forest.

Remarks. Females are difficult to separate from males, but when set side by side to a male they present a more simply angular anteromedian pronotal carina which is weakly tuberculate medially. As opposed to most other Scarabaeine, the 8th abdominal segment is not proportionally longer along midline in ventral view in females and thus of very limited help. No variation except for size and development of secondary sexual characters.

This species is extremely closely related to D. larseni . At this point, we are considering these two forms as distinct species, D. angustulus being the Guiana shield endemic and D. larseni the southern Amazonian endemic. However, at this time it is impossible to state if the two forms are allopatric or sympatric in distribution. If more material becomes available from the central Amazonian area with intermediate forms between D. angustulus and D. larseni this status will have to be reconsidered.

Figures

FIGURES 13 – 18. Dorsal habitus. 13. D. angustulus, male holotype; 14. D. ater, male neotype; 15. D. flechtmanni, male holotype; 16. D. larseni, male holotype; 17. D. piceus, male holotype; 18. D. telephus, 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.