Careocallus densicollis Cherman and Smith, 2024

Cherman, Mariana A., Basílio, Daniel S., Clarkson, Bruno, Agostinis, André O., Smith, Andrew B. T., Vaz-De-Mello, Fernando Z. & Almeida, Lúcia M., 2024, New and revised taxa of Neotropical Diplotaxini (Coleoptera: Melolonthidae): do they change the existing relationships? Revisiting systematics with morphological and molecular data, Zoological Journal of the Linnean Society 201 (1), pp. 98-135 : 130-131

Careocallus densicollis Cherman and Smith , sp. nov.

( Figs 10A–H , 11A )

ZooBank: urn:lsid:zoobank.org:act:A9BA395B-6B12-4F00-A1BB-EEA66C8972DF

Type material

Careocallus densicollis ♂ holotype ( CMNC): [white, outlined, typeset] ‘4-X-59/CIPOLLETTI/Prov. Rio Negro / Leg. S. Schajovskoy’, [red typeset and handwritten] ‘ CAREOCALLUS / DENSICOLLIS/HOLOTYPE/ Cherman M.A. & Smith, A.B. T.’, wing and genitalia mounted. Paratypes (nine) all with the label [yellow typeset and handwritten] ‘ CAREOCALLUS / DENSICOLLIS/PARATYPE/ Cherman M. A & Smith, A.B. T .’: one ♂ paratype ( CMNC) with the same labels of the holotype . Five ♂ paratypes ( CMNC), each with one number of the sequence: [typeset] ‘ PUNTA SIERRA /(350 M. S.N. M.) / NEUQUEN-ARG’. (typeset), ‘3- IV-75 /LG. M. GENTILI’, [typeset] ‘H.&A. HOWDEN/COLLECTION/ ex. A. Martinez coll.’, [typeset with data matrix code] ‘ Canadian Museum of/ Musée canadien de la/NATURE/ CMNEN 00029719–23 ’. One ♀ paratype ( CMNC): [handwritten by A. Martínez] ‘ ARGENTINA / Río Negro / Valcheta / Coll. Martínez / Dic. 992’, [typeset] ‘H.&A. HOWDEN/COLLECTION/ ex. A. Martinez coll.’, [typeset with data matrix code] ‘ Canadian Museum of/ Musée canadien de la/NATURE/ CMNEN 00029724 ’. One ♂ paratype ( CMNC): [handwritten by A. Martínez] ‘ ARGENTINA / Río Negro / S. Antonio Oeste / Zunizo-leg / Coll. Martínez / Ene. 976’, [typeset] ‘H.&A. HOWDEN/ COLLECTION/ ex. A. Martinez coll.’, [typeset with data matrix code] ‘ Canadian Museum of/ Musée canadien de la/NATURE/ CMNEN 00029725 ’. One ♂ paratype ( CMNC): [typeset] ‘JULIAN ROMERO/(200 M. S.N. M.)/ RIO NEGRO-ARG .’, ‘ 7-X-74/LG. M. GENTILI’ (typeset), [typeset] ‘H.&A. HOWDEN/COLLECTION/ ex. A. Martinez coll.’, [typeset with data matrix code] ‘ Canadian Museum of/ Musée canadien de la/NATURE/ CMNEN 00029726 ’.

Holotype and eight paratypes deposited at CMNC. One paratype deposited at CEMT.

Diagnosis

Body elongate, shiny, elytra purplish-red, unicolorous with the body or slightly lighter in colour ( Fig. 10A ); pronotal disc very coarsely punctate, denser towards the anterior margin, posterior corners in obtuse angle ( Fig. 10B ); elytral ridge barely or not elevated, apex of sutural ridge forming obtuse angle with the posterior margin of elytron; mesotibia subquadrate in cross-section ( Fig. 10C ); inner margin of metatibia carinate upon apex, expanded subapically ( Fig. 10D ); protarsomeres I–III barely enlarged; protarsal claw, superior tooth two-thirds the length of the protarsomere V; inferior tooth vestigial ( Fig. 10E ); pygidium sparsely bristled on apex, pygidial apex rounded ( Fig. 10F ); basal region of parameres very short, lateral margins expanded ( Fig. 10G ); apex of parameres spatulate, margins subangulate, straight coplanar in lateral view ( Fig. 10H ).

Holotype description

Length: 13.2 mm; width 6.5 mm. Purple. Head: frons somewhat swollen, almost as long as clypeus; clypeus trapezoidal, subemarginate medially; fovea of maxillary distal palpomere deep, not reaching the transverse midline; antenna with 10 antennomeres, club lighter in colour and longer than funicle. Thorax: pronotal disc ( Fig. 10B ) very coarsely punctate, dense except near the posterior margin; pronotal posterior corners in obtuse angle; hypomeron with long bristles and few scales on inner margin; metaventrite with scattered, short bristles; distance between mesocoxae and metacoxae twice longer than the metacoxa; scutellum ogival, few punctures at the sides. Elytra: shiny, uniform purple, unicolorous with pronotum; length almost three times that of the pronotum; sutural ridge slightly darker than elytron, not elevated; disc coarsely punctate; punctures forming three elytral ridges, the innermost more marked than the others. Legs: protibia with three teeth, the basal one slightly shorter than the others, the three teeth equally spaced; mesotibia subquadrate in cross-section; surface finely sculptured; mesotibia with two transverse carinae, the apical carina complete ( Fig. 10C ); inner margin of metatibia carinate towards apex, expanded subapically ( Fig. 10D ); metatibia with surface finely sculptured; two transverse carina present posteriorly, the basal carina weak; protarsomeres I–III barely enlarged; claws bifid, protarsal claw longer than the others, two-thirds the length of the protarsomere V; inferior tooth vestigial, raising next to the base of the superior tooth ( Fig. 10E ). Abdomen: ventrites sparsely bristled on disc; propygidium slightly visible, bristled; pygidium flat, subquadrate, as wide as it is long; pygidial disc sparsely bristled on apical portion, bristles long; pygidial apex rounded ( Fig. 10F ). Parameres: lateral margin of basal region expanded at a plane below the dorsal; parameral split at the first third; inner margins straight; apex spatulate, subangulate ( Fig. 10G ); parameres straight in lateral view, apex flattened ( Fig. 10H ).

Variation

Male paratypes: Length: 9.7–13.2 mm; width 5.0– 6.8 mm. As the holotype except in the elytra lighter in colour, disc with punctures finer; and pronotal disc densely punctate throughout.

Female paratype: Length: 10.7 mm; width 6.2 mm. As for the holotype, except in the body strongly oval; distance between mesocoxae and metacoxae 1.5 times the length of the metacoxae; hindwings brachypterous (elytra fused); inner margin of metatibia not carinate; pygidial apex rounder. The type series of this new species is composed by specimens of historical collections, which were not able to be submitted to molecular extractions. These specimens have enough features that justify the description of this other species in Careocallus .

Etymology

Adjective in the nominative singular. From the Latin dēnsus (‘dense, close, frequent’) + from the Greek - collis (‘neck’, related to the pronotum). The species name is based on the dense punctation of the pronotum.

Type locality ARGENTINA.RioNegro,Cipolletti[38°56ʹ18.2ʹʹS67°59ʹ48.8ʹʹW].

Geographical distribution

ARGENTINA (Neuquén, Río Negro).

Remarks

Careocallus densicollis resembles C. tehuelche in colour, shape of clypeus, pronotum, and pygidium. Differs mainly ( C. tehuelche in parenthesis) in the elytra flatter; the apex of the sutural ridge in obtuse angle (angle 90º); protarsal claw with superior tooth longer, two-thirds the length of the protarsomere V, and inferior tooth vestigial (one-half the length of protarsomere V, inferior tooth noticeably shorter than superior tooth but not vestigial); males with basal transverse carina on metatibia very weak, apical transverse carina only posteriorly (apical carina extending across the disc); inner margin of metatibia expanded subbasally (straight); and in the shape of the parameres, with lateral margin expanded basally and apex with margin subangulate (lateral margin of basal portion not expanded, apex with margin rounded).

This species could be confused with Liogenys densata Frey, 1969 (see Cherman et al. 2021: Fig. 4 ), regarding the colour, the mesofemur long and uniform in width; and somewhat in the subapical callus of elytra less marked compared with other Liogenys species. However, L. densata is easily recognizable by consistent characters present in Liogenys , such as the indented and strongly emarginate clypeus; posterior corners of pronotum forming a more closed angle; elytra finely punctate; four elytral ridges instead of three, apex of sutural ridge rounded; and other diagnostic features of the species itself, such as the pronotal disc very finely punctate and the dense scales covering the thorax laterally, ventrites, propygidium, and pygidium.

Taxonomic remarks on Pseudodiplotaxis Pseudodiplotaxis is represented only by Ps. albosetosa , reportedly from western Brazil, Rio Xingú ( Nonfried 1894). The identity of this taxon is quite enigmatic, since it was not possible to locate the primary type, or any other non-type material matching with this identification. Vaurie (1958) has already stated that this type is lost, and despite the details in the original description, she did not give any clue about the placement of this taxon in a species group within Diplotaxis . Also, Moser (1912), in his study on Nonfried types, found inconsistences about their type localities and generic identity. For instance, Diplotaxis wittkugeli Nonfried is an Apogonia species apparently from the Indian region and not from Honduras, as originally stated by Nonfried (1894). The same happened with Trichoderma ceylonica Nonfried , now placed in Plectris , which is a species from Paraguay and not, as stated by Nonfried (1894), from Ceylon. This is the case with five other names among Coleoptera . This background demonstrates that the type locality of Pseudodiplotaxis is not trustworthy, and this makes it more difficult to assign a correct genus or even a tribe to this taxon. According to the generic description, Pseudodiplotaxis shows the following combination of features: head one-third narrower than the pronotum, clypeus subquadrate, margin flanged; eyes obtuse triangular; antenna with 10 antennomeres, club fusiform with three lamellae; pronotum strongly convex, anterior half narrower, posterior margin with same width as elytra, lateral margins unevenly curved and carinate; anterior corners projected, posterior corners blunt; elytra convex, elongate, without recognizable ridges except for the sutural ridge, humeral and subapical callus protruding and carinate; protibia with three teeth, the basal tooth inconspicuous and the apical strong, inner spur strong, opposite to the middle tooth; mesotibia with a weak transverse carina; metatibia smooth; tarsi slender, bristled, claws bifid; propygidium with ring that coincides with posterior margin of elytra; pygidium small, semicircular. In addition, specific features of Ps. albosetosa are: body length 11 mm; dorsally shiny, brown, lighter towards the elytral ridge, coarsely punctate, entirely bristled; ventrally covered with white scales; clypeus slightly sinuate anteriorly. According to Nonfried (1894), this genus is similar to Diplotaxis with regard to the mouthparts (except for the bordered labrum); the small, rounded pygidium and the shape of the bifid claws. It differs from Diplotaxis in the shape of the eye and ocular canthus and the absence of ridges on elytra, which has in common with Schizonycha and Phyllophaga (Chlaenobia) . According to the data provided by the description, we can confirm that this taxon is not a Neotropical Diplotaxini (eyes triangular, labrum bordered, elytra without ridges, small pygidium). The clypeus subquadrate, triangular eyes, posterior margin of pronotum matching with the elytra in length, ring on the propygidium, and small pygidium could fit in Apogonia , except for the narrow, slender shape of body and tarsi, the absence of ridges on elytra, and the bordered labrum. The characters could also apply to some genera of Macrodactylini and Melolonthini. Due to the vague evidence that could place this taxon in three different tribes of Melolonthinae, Pseudodiplotaxis is here transferred from Diplotaxini to Melolonthinae incertae sedis.

Figures

Figure 4. Diagnostic features and transformations that support Homalochilus. Head in dorsal view (A), head and anterior portion of prothorax in dorsolateral view (B); head in frontal view (C); maxilla (D); labium (E); elytra, white square indicates erect setae (F); head, pronotum, scutellum and proleg (G), thoracic and abdominal ventrites, white lines indicate size of ventrites (H). White arrows in each figure indicate transformations and/or detailed features.

Figure 10. Careocallus densicollis. Male holotype habitus (A); head and pronotum (B); lateral (C) and posterior (F) views; metatibia (D); protibial claw (E); parameres in dorsal (G) and lateral (H) views.

Figure 11. Hindwing in Careocallus. Careocallus densicollis male (A); Careocallus tehuelche male (B) and female (C).