Liogenys niger Cherman & Basílio & Clarkson & Agostinis & Smith & Vaz-De-Mello & Almeida 2024
Creators: name: Cherman, Mariana A.
name: Basílio, Daniel S.
name: Clarkson, Bruno
name: Agostinis, André O.
name: Smith, Andrew B. T.
name: Vaz-De-Mello, Fernando Z.
name: Almeida, Lúcia M.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Liogenys
Liogenys niger

description: Liogenys niger (Blanchard, 1851) comb. nov. (Fig. 7A–K)
Homalochilus niger Blanchard 1851: 172 (original description); Harold 1869: 1141 (catalogue); Borre 1871: XXIII (catalogue); Kolbe 1907: 65 (catalogue); Bruch 1911: 201 (catalogue); Dalla Torre 1913: 319; Blackwelder 1944: 228 (catalogue); Gutiérrez 1952: 213, 214 (key, redescription); Smith 1987: 62 (catalogue); Evans 2003: 11, 206 (systematics, catalog); Evans and Smith 2005: 170 (catalogue); Evans and Smith 2009: 174 (catalogue); Krajčík 2012: 128 (catalogue); Cherman et al. 2016: 765 (systematics); Cherman et al. 2017:18, 34 (systematics).
Liogenys morio Burmeister 1855: 16 (original description); Harold 1869: 1141 (catalogue); Bates 1887: 155 (redescription); Kolbe 1907: 65 (catalogue); Bruch 1911: 200 (catalogue); Dalla Torre 1913: 318 (catalogue); Blackwelder 1944: 227 (catalogue); Gutiérrez 1952: 211 (Homalochilus redescription); Evans 2003: 211 (catalogue); Evans and Smith 2005: 175 (catalogue); Evans and Smith 2009: 179 (catalogue); Krajčík 2012: 145 (catalogue); Cherman et al. 2016: 765 (systematics); Cherman et al. 2017: 4 (taxonomic history). syn. nov.
Type material examined
Homalochilus niger ♀ lectotype, present designation (MNHN): [white handwritten] ‘6045/34’, [light green typeset] ‘MUSÉUM PARIS/[handwritten] Patagonie/d’Orbigny’, [green handwritten] ‘O. [sic] niger /Cat Mus/Patagonie/M. d’Orbigny’, [red typeset] ‘SYNTYPE’, [white, outlined in red, typeset] ‘ LECTOTYPE / Homalochilus niger / Blanchard 1851 /[des.] M. A. Cherman 2015 ’. Female paralectotype (MNHN): [white handwritten] ‘6045/34’, [light green typeset] ‘MUSÉUM PARIS/PATAGONIE/(PATAGONES)/D’ORBIGNY 1834’, [white, typeset in red] ‘COTYPE’, [red typeset] ‘SYNTYPE’.
Liogenys morio ♂ neotype, present designation (MLUH): [green handwritten] ‘morio [underlined] Burm/Bras. Dp [Dupont]’, [white handwritten by Darwin] ‘B. Blanca’, [red handwritten] ‘ LIOGENYS /MORIO/Burm, 1855/ NEOTYPE /des. Cherman M. A.’.
Non-type material examined
BRAZIL. Without locality and date, 3♀ (ZMHB); São Paulo: Itapena, II.1983, J.N. Pedrosa Macedo coll., 4♂ (DZUP).
ARGENTINA. Misiones: Pindapoy, X.1955, Bosq coll., 1♀ (MZUC); Pindapoy, XI.1945, 2♀ (CMNC); Loreto, ExperimentalStation,A. Ogloblin, 2♀ (CMNC); Loreto, without collector, IX. 1959, 1♂; II.1960, 1♂ (NHMB); Córdoba: Alta Gracia, Sierras de Córdoba, I.1938, C. Bruch, 1♂ and 1♀ (MLPA); Entre Ríos: Departamento Concordia, Salto Grande,
VIII.1979, 1♀ (CMNC); San Luis: Departamento Capital, San Jerónimo, I.1979, Guillimer coll., 1♀ (CMNC); Buenos Aires: Bahia Blanca, C. Darwin coll., 8♂ 1♀ (BMNH); without locality, I.1938, C. Bruch coll., 1♂ (MLPA); without date, Frobert coll., 1♀ (ZMHB); Felipe Solá, II.1942, Martin Coll., 1♂ and 6♀ (CMNC); Felipe Solá, XII.1944, 1♀ (MZUC); Puán, XII.1961, A. Martinezcoll., 1♂ and 3♀ (MZSP); Patagonia [probablyBahia Blanca], Darwin coll., 3♀ (MLUH). URUGUAY. Montevideo, without date, Tremoleras coll., 1♂ (MLPA).
Diagnosis
Length: 8.7–10.5 mm; width: 4.8–6.2 mm. Body short, oval; body and elytra in general black (Fig. 7A, B), elytra glabrous, eventually reddish-brown on disc and black on scutellum and surrounding (Fig. 7C); shiny or semiopaque, coarsely punctate; pronotum with slight iridescent green reflections; distance between eyes more than five times wider than one eye; clypeus and frons almost coplanar; clypeus very wide, subemarginate; clypeal emargination small, shallow, rounded, and narrow; clypeal lateral margin convex; ocular canthus exceeding the outer margin of the eye; galea of maxilla with four strong teeth; distal maxillary palpomere oval, fovea very shallow, hardly reaching the midline of the palpomere; labium transversely carinate, as wide as it is long; two labial palpomeres equal in length; antenna with 10 antennomeres; club unicolorous with the funicle and as long as; pronotal anterior margin concave and slightly produced medially; pronotal disc strongly and coarsely punctate, posterior corners rounded; distance between mesocoxae and metacoxae slightly longer than metacoxa; scutellum wide; elytra convex dorsoventrally (Fig. 7G), nearly 2.5 times longer than the pronotum; three elytral ridges noticeable (I, II, and IV); subapical callus above the level of the distal inner corner of the sutural ridge; mesotibia cylindrical and with transverse carina complete in both sexes; metatibial spurs slightly uneven, the longest slightly shorter than the diameter of the tibial apex; ventrites II and III with tubercle at the midline (Fig. 7H); propygidium glabrous, almost entirely covered by the elytra; pygidium convex, especially in females; wide; subtrapezoidal; pygidial disc glabrous, coarse umbilicate punctures (Fig. 7I); in males inner margin of metatibia strongly carinate and produced from medial portion towards apex; inner surface with dense, thick bristles, bristles almost as long as the metatibial width; pro- and mesotarsomeres I to IV enlarged; protarsomere II as wide as it is long; claw bifid on all legs, symmetrical; basal region of parameres long, more or less compressed proximally, abruptly bulged subbasally, swollen, and narrowed at the midline; parameral split after the midline; longitudinal sulcus deep; inner margins of parameres straight; expanded apically, apical margin rounded; parameres in lateral view slightly concave, coplanar (Fig. 7J, K).
Type locality
Homalochilus niger: ARGENTINA. Buenos Aires, Bahía de San Blas. Liogenys morio: ARGENTINA. Bahia Blanca.
Geographical distribution
BRAZIL (São Paulo); ARGENTINA (Misiones, Entre Ríos, Córdoba, San Luis, Buenos Aires); URUGUAY (Montevideo).
Liogenys niger taxonomic history and remarks on systematics
Blanchard (1851) described Homalochilus niger based on a series of two females collected by A.D. d’Orbigny from Bahía de San Blas, Buenos Aires. The features mentioned by the author were the body coarsely punctate, entirely black; clypeus poorly emarginated; scutellum almost smooth; elytra short and wide, convex; protibiae tridentate and tarsi black.
Burmeister (1855) described a male specimen of Liogenys morio as oval, shiny, punctate; black with copper reflections on pronotum; and clypeus emarginated, subindented. He stated that the species resembles L. obesa Burmeister (current synonym of L. concolor Blanchard) (Cherman et al. 2017) in the short, convex, oval body. This short body is due to the distance between mesocoxae and metacoxae slightly longer than the metacoxa, an uncommon feature in most Liogenys (Cherman et al. 2016, 2017) which have this distance two times longer than the metacoxa. Other morphological features that these species share are the elytra convex, less than three times the length of the pronotum; distal maxillary palpomere oval; and antenna almost entirely black (Cherman et al. 2017).
Bruch (1911) expanded the distribution of L. morio to Buenos Aires, Cordoba, Chaco, and ‘Patagonia’.
Frey (1969) stated that the type of L. morio had been lost, and therefore he was unable to treat the species in his revision of Liogenys.
At MLUH we found a series of two males and two females, accompanied by the typical green square label of Burmeister’s types at the bottom of the drawer (Fig. 7D). On the label it is handwritten: ‘morio Burm /Bras [Brazil] Dp [probably Dupont]’, and this locality does not match with the one stated at the original description: ‘Mittel Amerika’. Moreover, two out of the four specimens bear a handwritten, white label: ‘ Bahia Blanca’ and ‘Patagonia, Darwin’, respectively, which does not match either with the description, or the drawer’s label. In the original ‘Handbuch’ housed at the MLUH, ‘Mittel Amerika’ is struck through and ‘Patagonien’ has been handwritten above. Using handwriting comparisons, this information might have been written by Harold (Horn and Kahle 1937). Moreover, this locality record was used consistently since Harold (1869: 1141), so we can infer that the series we found has been there, at least, since that date. Bates (1887) mentioned that no specimens were found in Central America matching with L. morio. There is another species, Diplotaxis micropyga (Burmeister) (Cherman et al. 2016), which was described even on the same page as L. morio and its type locality is ‘Brasil’. Diplotaxis is mostly Nearctic, although one species was recently recorded in Colombia, becoming its southernmost occurrence (Mendoza and García-Atencia 2019). Germar wrote the square labels to Burmeister, so he might have accidentally switched the type labels of L. micropyga and L. morio. In the description of L. morio, Burmeister did not mention any information about who was either the collector or the owner of the material. However, judging from what is written in the green label of the drawer, Burmeister received those specimens from Henry Dupont (1798–1873), who was a prolific dealer of beetles during the first half of the nineteenth century, and probably the seller of Darwin’s specimens deposited at the MLUH. In order to clarify the taxonomic status of the name by fixing it to a specimen, according to Article 75.3 of the International Code of Zoological Nomenclature (1999), the specimen found at the MLUH was selected as the neotype of L. morio (Fig. 7A, D, E).
After the study of Homalochilus niger (MNHN) and Liogenys morio (MLUH) type series, we concluded that they are conspecific, with Liogenys morio being the junior subjective synonym of Homalochilus niger (L. niger comb. nov.). Although the specimens from ‘Brazil’ and Misiones (Argentina) do not have the ventrites II and III with tubercles at the midline and the parameres show some variations in shape, we considered those as intraspecific variations.
In the phylogenetic hypothesis of Cherman et al. (2016), H. niger (hereinafter L. niger) and L.concolor are not closely related species, due to miscoded characters already discussed in this text. The present hypotheses from equal weighting and implied weighting analysis show support (ABS = 4/SR = 56; RBS = 35/SR = 78, respectively) in L. niger being nested within Liogenys. This inclusion does not significantly change the diagnosis of the genus (Cherman et al. 2017), though L. niger includes some exceptions among the genus Liogenys: clypeus in lateral view straight, not sinuous (12:1); labrum bulging on superior margin (38:0); and setae on mesotibial carina longer than the apical (84:0). All characters supporting Liogenys in Cherman et al. (2016) are also in the present hypotheses, including its synapomorphy (Table 1). Character 156:1 (Fig. 12C), coded for the first time, also supports the clade, and thus, is a new contribution to the diagnosis of Liogenys.
The implied weighting analysis (Fig. 2) solved the relationships within Liogenys better than the equal weighting analysis, where the clade containing L. niger collapsed with 10 other lineages (ABS = 1/21). In the former analysis, L. niger is the sister-clade of L. concolor (RBS = 28/SR = 26), supported by four transformations (Table 1). The body convex, slightly depressed posteriorly (59:0); the pronotum with posterior angles slightly projected (48:0); and the apex of the scutellum rounded (56:0), are similarities already mentioned by Burmeister (1855).
description: Published as part of 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, pp. 98-135 in Zoological Journal of the Linnean Society 201 (1) on pages 116-119, DOI: 10.1093/zoolinnean/zlad115, http://zenodo.org/record/11241094