Liogenys maxillaricuspis Cherman, 2020

Cherman, Mariana A., Basílio, Daniel S., Mise, Kleber M., Frisch, Johannes, Smith, Andrew B. T. & Almeida, Lúcia M., 2020, Liogenys Guérin-Méneville, 1831 (Coleoptera: Scarabaeidae: Melolonthinae) from the southern South American Transition Zone and boundaries: taxonomic overview with four new species, Zootaxa 4896 (1), pp. 46-84 : 69-70

Liogenys maxillaricuspis Cherman , new species

Figs. 8 A-I; 12 E-F; 13 A, C, G; 15

Type material. Holotype, male, labeled ( CMNC): [white typeset] “ ARGENTINA: Rio Negro / Dto Gral Roca, Catriel / 37º52’30’’S 67º5’10’’W / 4 Jan. 2005, 311 m / F.C. Ocampo ”, [red typeset and handwritten] “ LIOGENYS / MAXILLARICUSPIS / HOLOTYPE / Cherman M.A.”, genitalia mounted . Paratypes (84) labeled [yellow typeset and handwritten] “ LIOGENYS /MAXILLARICUSPIS / PARATYPE / Cherman M. A.”: Seven males and six females with the same data of the holotype ( DZUP). Three males and two females with the same data of the holotype ( CEMT). Thirty one males and twenty eight females with the same data of the holotype ( CMNC). The males with the following sequence of vouchers: [typeset with data matrix barcode] “Canadian Museum of / Musée canadien de la / NATURE / CMNEN 00029648–81 ”. The females with the following sequence of vouchers: [typeset with data matrix barcode] “Canadian Museum of / Musée canadien de la / NATURE / CMNEN 00029682–713 ”. Eight specimens with the same data as the holotype, and DNA stored in alcohol at -80ºC and the following voucher numbers ( CMNC): Four males with the sequence: [typeset with data matrix barcode] “SCARABS OF / SOUTHERN / SOUTH AMERICA / SSSA3003308–11 ”. Two females with the sequence: [typeset with data matrix barcode] “SCARABS OF / SOUTHERN / SOUTH AMERICA / SSSA3003312–13 ”. One female [typeset with data matrix barcode] “SCARABS OF / SOUTHERN / SOUTH AMERICA / SSSA3003306 ”, [typeset] “A.B. T. SMITH DNA / 28S/18S VOUCHER / SPECIMEN SMI-131”. One female: [typeset with data matrix barcode] “SCARABS OF / SOUTHERN / SOUTH AMERICA / SSSA3003307 ”, [typeset, outlined black]. “A.B. T. SMITH SCARAB / DNA VOUCHER / SPECIMEN / AS498 / JULY 2005 ”. One male and one female paratype ( IADIZA) labeled: [white typeset] “Arg. Rio Negro / Gral. Rocas / Cnia. Catriel 311 m / S. Roig / G. Flores / 04/I/05”, [white typeset] “ 37º52.83’S / 67º56.16’W ”. One male ( CMNC): [white typeset] “ ARGENTINA, Pr. San Luis / 18 km S Arizona / 18-23.I.1982 [space] 250 m / H & A Howden”. One male and three females ( VMDC): [typeset] “Argentina Chubut / Gaiman, Bryn Gwyn / 4 Noviembre 2008 / Leg. Daniel Rojas L.”. The male with the voucher: [typeset with data matrix barcode] “SCARABS OF / SOUTHERN / SOUTH AMERICA / SSSA3002827 ”. The females with the sequence of vouchers: [typeset with data matrix barcode] “SCARABS OF / SOUTHERN / SOUTH AMERICA / SSSA3002860–62 ” .

Holotype and 68 paratypes at CMNC. Five paratypes deposited at DZUP. Five paratypes deposited at CEMT. Two paratypes deposited at IADIZA. Four paratypes deposited at VMDC.

Diagnosis. Body elongate, dull yellow ( Fig. 8A ); pronotum slightly darker and slightly wider than the humeral distance; margin of clypeus, pronotum and protibia darker; frons swollen, coarsely punctate; antennae with 9 antennomeres; clypeal emargination deep, narrowed, rounded; teeth subangulate ( Fig. 12 E–F); clypeal lateral margin convex; pronotal posterior corners rounded ( Fig. 8B ); elytra with sparse, random bristles; males and females with one metatibial transverse carina complete, inner margin not carinate; pygidium with sparse, long bristles; smooth, as

long as wide ( Fig. 8E ); inner margins of parameres straight, opened, apex spatulate, apically slightly divergent and curved downwards, lateral margins of apex below the plane of the parameres ( Fig. 8 F–H).

Holotype. Male. Length: 7.8 mm; width: 3.5 mm. Dull yellow. Head: distance between eyes slightly more than twice the width of one eye; frons swollen, equal in length to clypeus; frontoclypeal surface with few bristles; anterior margin of clypeus dark in color ( Fig. 12 E–F); clypeal emargination shallow, wide and rounded; outer sides of anterior teeth subparallel; clypeal lateral margin convex, not produced; distal maxillary palpomere, maximum width slightly wider than apex; fovea deep, extending up to the transverse midline of the palpomere; antenna with 9 antennomeres, club lighter in color and longer than the funicle. Thorax: anterior margin of pronotum slightly produced medially, pronotum anteriorly narrowed forming a depressed ring; pronotal disc with punctures coarse and very sparse; posterior corners rounded; hypomere with long bristles; mesepisternum, sides of metaventrite and metacoxae with sparse bristles; distance between mesocoxae and metacoxae less than twice the metacoxa length; scutellum ogival, finely punctate throughout and with bristles. Elytra: disc shiny; bristles on disc disposed randomly; elytral suture and elytron unicolored, not elevated; two inner elytral ridges more defined than the outer ridge, third ridge undistinguishable. Legs: procoxa with bristles and punctate; protibia with three teeth, almost equal in size and equally spaced; mesotibia cylindric, somewhat flattened in cross section; mesotibial surface finely sculptured; mesotibia with two transverse carinae, the apical carina complete; inner margin of metatibia not carinate; surface finely sculptured; metatibia with two transverse carinae, the apical carina complete; metatibial apical spurs with different lengths, the longer spur equal to the diameter of the tibial apex; metatarsomere I slightly shorter than tarsomere II; protarsomeres I–IV slightly enlarged, protarsomere II elongate; claw bifid, symmetrical, superior tooth of claw longer and equal in width to the inferior tooth; distance between teeth longer than the length of inferior tooth. Abdomen: ventrites with uniform and sparse bristles at the disc and sides; propygidium with bristles; pygidium slightly convex; subquadrate; as long as it is wide; pygidial width not exceeding distance between spiracles of propygidium; pygidial disc almost smooth, few punctures at the sides, sparse, long bristles throughout; pygidial apex rounded. Parameres: basal region as wide as both sections of the parameres at its maximum width, parameral split at 2/3 the length of the basal region; inner margins straight, opened, apex spatulate, apically slightly divergent and curved downwards; parameres in lateral view straight, coplanar ( Fig. 8I ).

Variation. Male paratypes. Length: 7.1–9.4 mm; width: 3.4–4.5 mm. As the holotype, except in the clypeal lateral margin produced (the most in male from San Luis) ( Fig. 8C ), and in the deepness of the pronotal punctures, some of them being shallower. Female paratypes. Length: 8.9–9.0 mm; width: 4.2–4.3 mm. As the holotype except in the size larger, the lateral margin of clypeus sometimes more convex ( Fig. 12F ) and the pronotal punctures deeper.

Etymology. Adjective in the nominative singular. Prefix from the Latin maxillaris (“related to the maxilla: set of paired mouthparts used to manipulate food”) + from Latin cuspis (“sharp point”). Liogenys maxillaricuspis new species is characterized by having a maxilla furnished with only one, strongly sharp, curved teeth, which can be seen with lowest magnification (6x) in ventral view of the head ( Fig. 13A, G ). This feature is unique among Liogenys species.

Type locality. ARGENTINA, Río Negro, Departamento General Roca, Catriel , 37º52’30’’S 67º5’10’’W .

Geographical distribution. ARGENTINA (San Luis, Río Negro) .

Remarks. Liogenys maxillaricuspis new species resembles L. rufoflava in the body size and color, elytra with bristles, and somewhat in the shape of the bristles on the pygidium, although the bristles are sparser and longer. Liogenys maxillaricuspis new species has unique characters for the genus, especially the mouthparts, but also the elytral ridges and the setae on tibial carinae. In addition to the already mentioned single morphology of the maxilla, the ligula of the labium is shorter than other species, with margin almost straight, without lobes ( Fig. 13 C–D). Since this new species has most of the synapomorphies of Liogenys ( Cherman et al. 2016) , we are describing it in this genus. New molecular phylogeny testing Diplotaxini relationships is being carried out and will bring light about the real position of this species among the Liogenys and other Diplotaxini lineages. The male paratype (CMNC) from San Luis province [18 km S Arizona / 18-23.I.1982 [space] 250 m / H & A Howden] shows slight variations in the shape of the clypeus and in the parameres when compared with the Patagonian specimens ( Figs. 8C, G ). However, we considered it to be L. maxillaricuspis new species because the maxilla has one tooth ( Fig. 13 G ), which is distinctive of this new species.

Figures

FIGURE 8. Liogenys maxillaricuspis Cherman, new species, male holotype views: A) dorsal, B) clypeus and pronotum, C) variation of clypeus, D) lateral, E) pygidium, and parameres views: F) dorsal, G) dorsolateral, H) arrows indicating variations in shape, I) lateral.

FIGURE 12. Dimorphism in clypeus. Liogenys lucialmeidae Cherman, new species: A) male, B) female; L. martinezi Cherman, new species: C) male, D) female; L. maxillaricuspis Cherman, new species: E) male, F) female.

FIGURE 13. Liogenys maxillaricuspis Cherman, new species: A) head in ventral view, C) labium, G) right maxilla; L. brachyclypeata Cherman, new species: B) head in ventral view, D) labium; L. calcarata Frey, 1970: E) left maxilla; L. xanthocera Harold, 1869: F) right maxilla. Legends: A, B) CLP: clypeus, LBM: labium, LBR: labrum, MXL: maxilla, MXLP: maxillary palp. C, D) LGL: ligula, LPLP: labial palp, MTM: mentum, PMTM: postmentum.