Dasyus LePeletier & Audinet-Serville, 1828

Fuhrmann, Juares, 2019, Taxonomy of Neotropical genera Compsodactylus and Dasyus and notes on claw movement in Macrodactylini (Coleoptera: Scarabaeidae: Melolonthinae), Zootaxa 4679 (1), pp. 139-163 : 142-144

publication ID	https://doi.org/ 10.11646/zootaxa.4679.1.9
publication LSID	lsid:zoobank.org:pub:D4C36872-B5F6-4007-962D-ABD17CED9BF7
DOI	https://doi.org/10.5281/zenodo.5874100
persistent identifier	https://treatment.plazi.org/id/6902F102-7937-046E-FF48-4A6B15DFFF2D
treatment provided by	Plazi
scientific name	Dasyus LePeletier & Audinet-Serville, 1828
status

Treatment

Dasyus LePeletier & Audinet-Serville, 1828: 369 ; Latreille 1829: 562; Guérin-Méneville 1830: 85, 90; Erichson 1845: 655; Desmarest 1851: 68, 131; Rühl 1888: 74, 1889: 59.

Type species. Dasyus collaris LePeletier & Audinet-Serville, 1828 (designation: monotypy).

Diagnosis. Pronotum covered with thin setae ( Fig. 24 View FIGURES 24–26 ), prosternum with an anterior longitudinal carina ( Fig. 40 View FIGURES 38–45 ); limit of mesoscutum–scutellum angulate ( Figs. 46, 51–52 View FIGURES 46–51 View FIGURES 52–56 ); protibia with two outer teeth and a spur ( Fig. 41 View FIGURES 38–45 ); medial area of mesotibia and metatibia as wide as apex ( Figs. 42–44 View FIGURES 38–45 ); protarsal claw bifid ( Fig. 41 View FIGURES 38–45 ), mesotarsal and metatarsal claws simple ( Figs. 42–44 View FIGURES 38–45 ); ventrite VI of males with a concavity ( Figs. 25–26 View FIGURES 24–26 ).

Description. Body ( Fig. 24 View FIGURES 24–26 ) length: 7.2–12.8 mm, greatest width at half of elytra: 3.8–5.8 mm; dorsal surface shiny and with hair-like setae. Sexual dimorphism evident, females slightly larger than males, ventrite VI of males with a concavity ( Figs. 25–26 View FIGURES 24–26 ) and abdominal venter of females convex. Head with small eyes in dorsal view; epistomal suture slightly sinuous or straight (indistinct in some specimens of D. collaris ); frons with large and subcontiguous or confluent puncture. Clypeus rectangular or trapezoid, somewhat semicircular in females, wider than long (posterior width/length = 2.0–2.8), as punctate as frons; ventral area not vertically deflected; anterior and lateral margin slightly upturned; anterior and posterior angles rounded and slightly upturned or not, posterior angles not extended in front of canthus. Labrum horizontal and narrow. Epipharynx ( Fig. 27 View FIGURES 27–29 ) densely setose; anteromedial area with a transverse phoba; medial area with scarce small stout setae and scarce sensilla; posteromedial area with dense thin setae and some stout setae. Each side of preoral area ( Fig. 27 View FIGURES 27–29 ) with 4−6 anterior sensilla (3−4 contiguous), 3−4 inner sensilla, and 5−7 posterior sensilla. Mandible ( Figs. 30–32 View FIGURES 30–34 ) with incisor bearing an inwardly directed, wide tooth, dorsal area with two large punctures; molar ( Figs. 33–34 View FIGURES 30–34 ) transversely striated, distal striae of right molar with some minute teeth. Maxilla ( Figs. 35–37 View FIGURES 35–37 ) setose, cardus and stipes with some barbed setae ( Fig. 35 View FIGURES 35–37 detail), stipe with a large ventroproximal stout seta; galea bearing 8 inward directed teeth; lacinia with one tooth; palpomere I with a minute outer seta, III with about 5 long setae, IV with dorsoproximal striation. Labium ( Figs. 28–29 View FIGURES 27–29 ) longer than wide, submentum fused with gula; mentum with longitudinal groove; prementum fused with ligula and distal margin of ligula slightly emarginate, lobes of ligula separate from each other by a membranous line; palpus with three palpomeres. Dorsal area of ligula and hypopharynx ( Fig. 28 View FIGURES 27–29 ) densely setose, medial area with about 5 sensilla, lateral areas with a long outward directed seta, posterior area with a V-shaped phoba. Antennae with 9 antennomeres and 3 lamellae. Pronotum ( Figs. 38–39 View FIGURES 38–45 ) slightly wider than long (width/length = 1.1–1.3), widest at middle; distance between punctures 1–3 times longer than puncture diameter; anterior margin beaded, sometimes marginal bead medially indistinct, lateral margins beaded, anterior and lateral margins with some setae evidently longer than setae of disc, posterior margin not beaded; anterior and posterior angles obtuse, lateral angles rounded. Hypomeron separates from posterior fold of pronotum by an angulate margin ( Figs. 39–40 View FIGURES 38–45 ); dorsal area of posterior fold of pronotum separates from ventral area by an angulate margin ( Fig. 39 View FIGURES 38–45 ). Prosternum ( Fig. 40 View FIGURES 38–45 ) with a medial longitudinal carina; each precoxal area 2.5 times wider than long, smooth; posterior process ( Fig. 39 View FIGURES 38–45 ) rounded, wider than long and not prominent. Coxal cavities as wide as long ( Fig. 40 View FIGURES 38–45 ). Prothoracic leg ( Fig. 41 View FIGURES 38–45 ) with tibia bearing a spur and 2 outer teeth. Inner distal setae of tarsomeres I–IV similar to each other, inner setae of V similar to other area setae; claws bifid and abruptly curved; empodium short. Scutellum ( Figs. 52–53 View FIGURES 52–56 ) parabolic, about two times wider than long, limit of mesoscutum–scutellum angulate ( Figs. 46, 51–52 View FIGURES 46–51 View FIGURES 52–56 ). Mesoventrite ( Figs. 46, 50 View FIGURES 46–51 ) with a raised transverse carina. Elytron punctate, elytral striae inconspicuous; humerus convex; distal knob inconspicuous; outer, distal and inner distal margins beaded, laterodistal and distal margins with marginal membrane. Mesothoracic legs ( Figs. 42–43 View FIGURES 38–45 ) with femur long (length/width = 3.7–3.9). Tibia with carina I distinct and II distinct in females ( Fig. 42 View FIGURES 38–45 ) and reduced or indistinct in males ( Fig. 43 View FIGURES 38–45 ); inner area of males with long setal comb. Tarsomeres I–II of male with inner long setal comb ( Fig. 43 View FIGURES 38–45 ). Metanotum ( Figs. 48 View FIGURES 46–51 , 52 View FIGURES 52–56 ) 2.4 times wider than long. Metaventrite ( Figs. 49–50 View FIGURES 46–51 ) wide, with setae similar to dorsal surface setae, lateral setae longer than disc setae. Pterothorax pleuron ( Figs. 46, 50 View FIGURES 46–51 , 54 View FIGURES 52–56 ) with mesepimeron in contact with metaventrite, this contact separates the metespisternum from mesocoxal cavity. Metendosternite ( Figs. 47, 49, 51 View FIGURES 46–51 ) with anterior area prominent and acute in lateral view. Posterior wing ( Fig. 57 View FIGURES 57–63 ) with anterior margin setose, axillary sclerites as figured ( Figs. 58–63 View FIGURES 57–63 ). Metathoracic legs ( Fig. 44 View FIGURES 38–45 ) with coxa wide (length/outer width = 2.1) and contiguous, inner process rounded and wider than long ( Fig. 9 View FIGURES 9–20 ). Femur wide (length/width medial = 3.0–3.3), with two longitudinal carinae between trocanter apex and each femorotibial articulation. Tibia wide (length/medial width = 2.9–3.1), abruptly enlarged on first third, medial and distal areas with similar width, carina I slightly distinct, II reduced or indistinct; apex with 2 spurs ( Fig. 45 View FIGURES 38–45 ). Tarsomere IV with inner distal setae thicker than those of I, inner area of V with a raised carina and with some thin setae; pretarsal claws simple and gradually curved, empodium long. Abdomen ( Figs. 55–56 View FIGURES 52–56 ). Pygidium of males parabolic, that of females triangular, setose and punctate, puncture with lunular peripheral stria, females with posterolateral margins internally folded ( Figs. 80, 83 View FIGURES 78–83 ), fold as long as half of the external surface. Males with medial area of ventrite V as long as III–IV combined, that of females as long as II–IV combined ( Fig. 56 View FIGURES 52–56 ); males with medial area of ventrite VI two times longer than V, that of females as long as one-third of V ( Fig. 56 View FIGURES 52–56 ); males with ventrite VI bearing a concavity ( Figs. 25–26 View FIGURES 24–26 ); intersegmental membrane VII–VIII hidden or exposed in males when pygidium–ventrite VI are distended. Spiculum gastrale ( Fig. 64 View FIGURES 64–70 ) with proximal piece short; sternite IX narrow, transverse and with posterior setae. Aedeagus ( Figs. 65–70 View FIGURES 64–70 ) with phallobasis and its apodeme wide, apodeme with a ventral thickened area, dorsum with lateral oblique prominences; parameres with lateral concavity, apex acute and ventrally deflected, inner margins setose. Endophallus ( Figs. 73–77 View FIGURES 71–77 ) with a wide proximal piece and a narrow distal piece; proximal piece with a long dorsal lobe, a wide ventroproximal lobe, a small ventromedial lobe and a wide ventrodistal lobe; distal piece with 1 or 3 dorsal lobes. Female terminalia ( Figs. 78–83 View FIGURES 78–83 ) with proctiger membranous, indistinct, but with distal raspula ( Fig. 78 View FIGURES 78–83 detail); paraprocts articulate with internal fold of pygidium ( Figs. 80, 83 View FIGURES 78–83 ); gonocoxites long and setose. Internal genitalia ( Figs. 81, 83 View FIGURES 78–83 ) with spermatheca curved, duct opening posteriorly prominent, gland of spermatheca large and connected to the distal area of the duct.

Remarks. The genera Calodactylus Blanchard, 1850 and Dasyus are similar to each other, they are distinguished by mesotibial and metatibial enlargements: Calodactylus has a medial enlargement ( Fuhrmann & Vaz-de-Mello 2017: fig. 7E) and Dasyus has medial and distal areas with same width ( Figs. 42–44 View FIGURES 38–45 ). An evident characteristic of these genera is the simple mesotarsal and metatarsal claws, which also occurs in male Pectinosoma Arrow, 1913 and some species of Ancistrosoma Curtis, 1835 , Barybas Blanchard, 1850 , Ceraspis LePeletier & Audinet-Serville, 1828 , and Faula Blanchard, 1850 . Other conspicuous characteristic to both genera is the ventrite VI of males with a medial concavity ( Figs. 25–26 View FIGURES 24–26 ; see Fuhrmann & Vaz-de-Mello 2017: fig. 7B); that ventrite ornamentation is also found in males of Chariodema Blanchard, 1850 ( Fuhrmann & Vaz-de-Mello 2017: fig. 9A).