Dichotomius (Luederwaldtinia) tristis ( Luederwaldt, 1923 )

Montoya-Molina, Santiago & Vaz-De, Fernando Z., 2021, Taxonomic review of the Dichotomius (Luederwaldtinia) agenor species group (Coleoptera: Scarabaeidae: Scarabaeinae), European Journal of Taxonomy 734, pp. 1-64 : 50-53

Dichotomius (Luederwaldtinia) tristis ( Luederwaldt, 1923)

Fig. 17 , Map 10

Pinotus tristis Luederwaldt, 1923: 12 (original description).

Pinotus tristis – Blackwelder 1944: 208.

Dichotomius tristis – Roze 1955: 44.

Diagnosis

Dichotomius tristis is separated from other species in the group by the following combination of characters: median tubercle of cephalic carina weakly curved posteriorly and rounded-truncate on apex. Apex of lateral tubercles obtuse. External margin of hypomeron bearing single row of long setae. Metasternal lateral pilosity sparse. Metacoxae with single row of organized ocellate punctures.

Material examined

Holotype VENEZUELA • ♂; “VENEZUELA. 11.74” [white, hw]/ “HOLOTIPO” [red with black margins, p]/ “ Pinotus ♂ tristis L̹d. L̹d. Det. 23.” [white, hw]/ “18150” [white, p]; MZSP.

Additional material

BRAZIL – Roraima • 1 ♂, 1 ♀; Amajari Ilha de Maracá ; 3º30.690′ N, 61º35.303′ W; Floresta Amazônica, Pitfall with human faeces; 9 May 2009; R. Andrade leg.; CEMT • 3 ♂♂, 3 ♀♀; Serra da Moça ; primary forest; Jul. 1997; F.Z. Vaz-de-Mello leg.; CEMT .

COLOMBIA – Casanare • 2 specs; Had. Guarato ; 400 m a.s.l.; 5º19′ N, 72º19′ W; Feb. 1996; A. Lopera leg.; ECC • 2 specs; Pore , Vda. Altamira , Fca. La Esperanza ; 350 m a.s.l.; 5º42′26″ N, 76º3′3″ W; Oct. 2006; I. Quintero and L.E. Franco leg.; IAvH . – Cundinamarca • 1 spec.; Paratebueno, Fca. Palumea ; 232 m a.s.l.; 4º20′18.5″ N, 73º11′44.3″ W; 26 Jan. 2013; J.S. Cardenas leg.; IAvH . – Guaviare • 1 spec.; San José del Guaviare, Fca. Eli ; 200 m a.s.l.; Aug. 2016; A. Santos leg.; ECC . – Meta • 36 specs; Acacias, Fca. Buenavista ; 494 m a.s.l.; 3º57.534′ N, 73º41.951′ W; Aug. 2012; L.M. Isaza leg.; IAvH • 89 specs; Barranca de Upía, Fca. Guaycaramo ; 194 m a.s.l.; 4º26′9.9″ N, 72º58′18.4″ W; 14 Mar. 2013; J.S. Cardenas leg.; IAvH • 86 specs; El Dorado; 336 m a.s.l.; 3º42.34′ N, 73º32.56′ W; Llanos orientales ; Aug. 2012; L.M. Isaza leg.; IAvH • 1 ♂; Mozambique, Franja Bosque de galleria ; 190 m a.s.l.; Apr. 1996; Jorge A. Noriega leg.; CEMT • 2 specs; PNN, Tinigua, Rio Duda ; 350 m a.s.l.; 2º40′ N, 74º10′ W; Jan. 996; I. Jiménez leg.; IAvH • 1 spec.; Puerto López , El Naranjal ; 220 m a.s.l.; 4º5′14″ N, 72º57′30″ W; Feb. 1997; F. Escobar leg.; IAvH • 116 specs; San Martín, Fca. La Laguna ; 326 m a.s.l.; 3º42.251′ N, 73º32.33′ W; Sep. 2012; L.M. Isaza leg.; IAvH • 1 spec.; San Martín, Nuevo Caney ; 389 m a.s.l.; 3º31′40″ N, 73º14′40″ W; 13 Jul. 2016; C. Giraldo and A. León J. leg.; MUSENUV • 2 ♂♂; San Martín, Had. Tocancipá; 335 m a.s.l.; Sabana-Bosque ; Apr. 2006; J. Noriega leg.; CEMT • 1 spec.; Remolino, Cafam Llanos ; 200 m a.s.l.; Apr. 1996; A. Lopera and S. Amézquita leg.; ECC • 2 specs; Villavicencio, Via Pto. Colombia ; 150 m a.s.l.; 4º2′91″ N, 75º78′15″ W; Mar. 1998; A. Camacho leg.; IAvH . – Vaupés • 2 specs; RN Mosiro-Itajura (Caparú), Terrazas ; 100 m a.s.l.; 1º4′ S, 69º31′ W; Sep. 1995; A. Lopera leg.; IAvH . – Vichada • 16 specs; Cumaribo; 300 m a.s.l.; 4º36′33″ N, 67º51′52″ W; Selva de Mataven , bosque de cerro rocoso ; 6 Mar. 2007; L.E. Franco leg.; IAvH .

VENEZUELA – Amazonas • 1 ♀; 150 m a.s.l.; Aug. 2003; CEMT • 1 ♀; Atures, Puerto Ayacucho ; 112; 13 May 2004; D. García-Favreleg.; CEMT . – Aragua • 1 ♂; Cuyagua ; 50 m a.s.l.; 6 Jul. 2004; D. García leg.; CEMT • 1 ♀; NP, Henri Pitter , Choroní ; 29 Jul. 1992; Hornburg leg.; CEMT . – Barinas • 3 ♂♂, 3 ♀♀; Andrés Eloy Blanco, Res.For. Caparo, Est. Cachicamo ; 159 m a.s.l.; 07º28′16″ N, 71º03′18″ W; human faeces; 22–23 Aug. 2014; R Acconcia and J Gámez leg.; CEMT . – Táchira • 4 ♂♂, 3 ♀♀; San Cristobal, Parque Natural Paramillo ; Jul. 1993; J. Blanco leg.; CEMT • 1 ♂, 1 ♀; San Cristobal , Barrio El Lobo; Apr. 1984; B. Joffre leg.; CEMT • 1 ♂, 4 ♀♀; Palo Gordo, nr San Cristobal , La Alameda Farm; 1000 m a.s.l.; Apr. 1987; D. Havranek leg.; CEMT . – Vargas • 1 ♂, 1 ♀; Vargas , La Sabana ; 31 m a.s.l.; 10º35′46″ N, 66º16′50″ W; 22 Jul. 2009; P. Cely, M. Cordova and M. Nuñez leg.; CEMT . – Yaracuy • 1 ♂; Bolivar Aroa ; 1376 m a.s.l.; 10º0′0″ N, 68º0′0″ W; 20 Jul. 2009; M. Asmüssen, P. Colmenares and H. Martínez leg.; CEMT • 2 ♂♂, 1 ♀; Venezª [Venezuela]; BMNH .

TRINIDAD • 2 ♂♂, 1 ♀; 1904; F. Birch leg.; BMNH • 2 ♂♂; Antilles ; BMNH • 1 ♂; Sta. Margarita ; May 1942; B.W.I.; BMNH • 2 ♂♂; Sta. Margarita , Trinidad; Jun. 1942; B.W.I.; BMNH • 1 ♂; 1953- 636; Humphries. B.M. ; BMNH • 1 ♂; B.W.I. E.C. Humphries. B.M. ; BMNH 1953 -636 • 2 ♂♂; Sta. Margarita ; B.W.I.; Sep. 1942; E.C. Humphries. B. M; BMNH 1953-636 .

COUNTRY UNKNOWN • 1 ♂; No data; CEMT • 2 ♂♂, 1 ♀; 1918-14; Nevinson leg.; BMNH • 1 ♂, 1 ♀; Villa Paz; BMNH • 2 ♂♂; Las Adjuntas ; 959 m a.s.l.; July 1926; H.E. Box leg.; BMNH .

Redescription

Male

MEASUREMENTS. Length: 19.9 mm.

HEAD. Anterior dorsal surface rugose, extending posteriorly not reaching base of cephalic carina. Clypeus with central emargination separating two rounded clypeal teeth feebly curved dorsally. Cephalic carina higher than wide, anterior surface smooth. Median tubercle two and a half times as high as lateral tubercles, conical in shape, weakly curved posteriorly, apex rounded-truncated and never bifurcate. Apex of lateral tubercles obtuse ( Fig. 17C ). Ventral clypeal process truncate (see Fig. 2B ).

PRONOTUM. Wider than long. Anterior disc of pronotum presenting truncate declivity ( Fig. 17D ). Row of organized ocellate punctures along anterior and posterior margins, few on lateral margins. Pronotal median disc with fine punctures. Hypomeral disc punctures separated by three times diameter of a puncture, never smooth or lacking punctation. External margin bearing single row of organized long setae, all approximately of same length (see Fig. 2F ).

ABDOMEN. Mesosternum covered by large, ocellate setigerous punctures. Metepisternum surface shagreened microsculpture, displaying ocellate setigerous punctures. Metasternum setigerous punctures restricted mainly to lateral and anterior areas of mestasternal lobe, puncture diameter variable. Metasternal antero-median pilosity never connecting with lateral through margin of mesocoxa (see Fig. 2H ). Ocellate punctures along anterior margin of each sternite. Pygidium sides of basal margin bearing row of ocellate punctures.

ELYTRA. Interstriae smooth with fine randomly distributed punctures. Striae strongly marked, with ocellate punctures separated by diameter of a puncture on elytral disc.

LEGS. Metacoxa posterior edge bearing row of organized ocellate punctures, separated by diameter of a puncture.

PARAMERES AND LAMELLA COPULATRIX. As in Fig. 17 F–H.

Morphological variation

Females ( Fig. 17B )

As males except for the following characters:

HEAD. Completely transversely rugose, denser on anterior portion. Cephalic carina bituberculate. PRONOTUM. Surface covered by fine punctures, denser at antero-lateral edges, ocellate punctures of margins denser, distinct on lateral sides. Hypomeron setae longer and denser than in males.

Remarks

Dichotomius tristis has historically been misidentified, as it is commonly confused with D. agenor . The holotype that Luederwaldt (1923) used to describe the species was from Venezuela, lacking information on the specific locality. This species is known to occur in Colombia, Venezuela and Brazil below 1000 metres a.s.l., in the zones of Orinocoan piedmont, dry savannas or as stated by Morrone (2001), the provinces of Los Llanos Venezolanos and Roraima.

Figures

Fig. 17. Dichotomius tristis (Luederwaldt, 1923). A–B. Dorsal habitus. A. ♂. B. ♀. C. Anterior view of the cephalic carina, medial tubercle apically truncate. D. Lateral view of the pronotum, anterior declivity truncate. E. Ventral view of the metacoxa, displaying a single row of punctures on the posterior margin. F. Lateral view of the aedeagus. G. Ventral view of the aedeagus. H–I. Lamella copulatrix.

Fig. 2. General characters that help differentiate the species of the Dichotomius (Luederwaldtinia) agenor species group. A–D. Ventral clypeal process. A. Cordate as in D. agenor (Harold, 1869). B. Truncate as in D. sagittarius (Harold, 1869) stat. rev. C. Bifurcate as in D. belus (Harold, 1880). D. Cylindrical as in D. henripittieri sp. nov. E–F. Hypomeral characters. E. Medial disc smooth, lateral margin with multiple rows of setae as in D. amplicollis (Harold, 1869). F. Medial disc punctate, lateral margin with single row of setae as in D. tristis (Luederwaldt, 1923). G–H. Metasternum characters. G. Setigerous punctures from the medial and lateral edges joining throughout the margin of the mesocaxa as in D. enioi sp. nov. H. Setigerous punctures from the medial and lateral edges not joining throughout the margin of the mesocaxa as in D. centralis (Harold, 1869). I–J. Elytra interstriae. I. Smooth as in D. amplicollis. J. Shagreened as in D. agenor.