Ochraethes nigroapicalis, Pérez-Flores & Toledo-Hernández, 2022

Pérez-Flores, Óscar & Toledo-Hernández, Víctor H., 2022, Species delimitation in the genus Ochraethes Chevrolat, 1860 (Coleoptera: Cerambycidae), with description of two new species, European Journal of Taxonomy 845, pp. 1-29 : 13-16

Ochraethes nigroapicalis sp. nov.

urn:lsid:zoobank.org:act:6AEDB175-184D-49AB-AD23-AB37386DE4FA

Fig. 2

Etymology

The specific name nigroapicalis is composed from the Latin ‘ niger, nigra, nigrum ’, and ‘ apex, apicis ’, referring to pubescence patterns on male elytra, which is mostly black on the posterior half.

Material examined

Holotype MEXICO • ♂; Nayarit, 5–10 km W of Jala ; 8 Dec. 1990; E. Giesbert leg.; EMEC.

Paratypes (32) MEXICO – Jalisco • 8 ♂♂, 2 ♀♀; 3.4 km NW of Tequila ; alt. 1295 m; 25 Sep. 1976; C.D. George and R.R. Snelling leg.; LACM • 1 ♀; San Martín de Bolaños ; alt. 1400 m; 22–26 Oct. 1996; C. Cabello leg.; “selva baja caducifolia”; EBCC . – Nayarit • 1 ♀; same collection data as for holotype; EMEC • 4 ♂♂, 3 ♀♀; same collection data as for holotype; FSCA • 2 ♂♂, 1 ♀; San Juan, Sierra de San Juan ; 21.50432º N, 104.92461º W; 14 Oct. 2020; Fernando Amador Martínez leg.; CNIN • 3 ♂♂; Volcán Ceboruco , 8–12 km W of Jala; 4 Oct. 1990; J.E. Wappes leg.; JEWC • 1 ♀; 5–10 km W of Jala ; alt. 4000–5000 feet; 27 Sep.–6 Oct. 1991; E. Giesbert leg.; FSCA . – Zacatecas • 6 ♂♂, 3 ♀♀; 6 km SSW of Tepetongo ; 3 Oct. 1990; J.E. Wappes leg.; JEWC .

Description

Male (holotype)

COLORATION. Integument black on head, thorax, coxae, elytra, and abdominal ventrites I–III, and basal half of abdominal ventrites IV and V; reddish brown on antennae, palpi, legs, and posterior half of abdominal ventrites IV and V.

HEAD. Surface finely and densely punctate; with short bright yellow pubescence on frons, genae, gulamentum, and mouthparts, bright orange on vertex (yellow in some specimens), and dense, long, erect, homogeneous pale yellow (bright yellow in some specimens) setae. Frons 2.1× as wide as long; median groove defined; tentorial depression transverse superficial and incomplete. Eyes finely faceted, with interlobular space as long as width lower lobe; distance between upper eyes lobes 5.0× as wide as upper lobe; interantennal space 0.7× as long as scape. Antennal tubercles slightly elevated with distinct depression toward median groove. Genae small, 0.5 × as wide as of lower lobe. Anteclypeus 4.5× as wide as long. Labrum distinctly narrower than anteclypeus with straight sides. Gulamentum 3.2× as wide as long. Antennae 1.2 × elytral length, reaching posterior quarter of elytra, with sparse bright yellowish-white or pale yellow pubescence on scape, pedicel, and antennomeres III–VIII, mostly brown on antennomeres VII–XI, and long setae on scape, pedicel, and antennomeres III–X, mainly ventrally and toward apex; antennomere XI with apex rounded; antennal ratio based on length of antennomere III; scape = 1.20; pedicel = 0.58; IV = 1.00; V–VII = 1.22; VIII–IX = 1.00; X = 0.84; XI = 1.22.

THORAX. Prothorax 1.5× as wide as long, rounded laterally. Pronotum moderately finely punctate, with dense bright yellow pubescence and bright orange pubescence interspersed; on central area more orange, and with dense bright yellow (some brown) erect setae; base constricted laterally, and laterobasal area arched. Scutellum wider than long, apically rounded, densely covered with bright yellow pubescence. Elytra 2.2 × as long as wide, with dense bright orange pubescence (occasionally bright yellow in some specimens), and long brown (some ochre) setae on base and apex; without transverse bands of black pubescence on basal half; with contrasting maculae of bright yellow (occasionally pale yellow in some specimens) pubescence as follows: first on humeral area, subelliptical; second close to suture on basal third, elongated; third on middle of anterior half, semicircular; fourth before middle, subeliptical, oblique; posterior half mostly covered with black pubescence, except apex with orange and bright yellow pubescence, surrounding dark central pubescence (sometimes, dark pubescence absent in some specimens); sub-sutural costa distinguishable, more clearly on posterior third; parasutural region depressed, with it widest zone 0.4× as wide as an elytron; apex slightly obliquely truncate, with apicolateral projection reduced. Humeri elevated, with brown (sometimes ochre in some specimens) pubescence. Prosternum with dense pale yellow (bright yellow toward sides) pubescence and moderately erect pale yellow setae; prosternal process narrow and posteriorly arcuate, apex with rounded lobes. Mesoventrite anteriorly moderately elevated, mostly with dense whitish pubescence and scattered erect pale yellow setae; mesoventral intercoxal process broad, 0.6 × as wide as mesocoxal cavities, in lateral view just as elevated as mesocoxae, apex emarginate; mesanepisternum covered with dense bright yellow pubescence, abundantly punctate; mesepimeron with whitish pubescence. Metaventrite with dense pale yellow pubescence, apical projection rounded truncate; metanepisternum with bright yellow pubescence denser than on metaventrite. Legs with dense pale yellow pubescence on coxae, and femora, bright yellow on tibiae, and tarsi, some ochre on tarsi; metafemora reach apex of ventrite V, with apical projection reduced, obtuse; metatibiae with innermost spine just longer than outermost; metatarsomere I 1.15 × length of metatarsomeres II–V together.

ABDOMEN. Intercoxal process wide, gradually narrowed toward acute apex, with homogeneous pale yellow pubescence on middle and bright yellow toward sides, denser laterally and apically, and erect, sparse pale yellow setae; apex of ventrite V truncate and slightly crenulated.

MALE GENITALIA. Parameres moderately sclerotized, subparallel in ventral view, narrower toward apex; with short setae throughout and long apical setae; inter-parameres space acute; basal projection discontinued, very oblique in ventral view, extended to middle of each paramere ( Fig. 2E ).

Female

Similar to male. Antennae just surpassing half length of elytra, antennomeres IX–XI shorter and wider than in males. Elytra with two transverse, wide, subparallel black pubescent bands reaching suture on posterior half, first on middle and second on posterior third, wide, sub-parallel, reaching elytral suture. Metafemora slightly shorter than in male. Apex of ventrite V rounded.

Dimensions (mm)

Holotype male. Total length, 13.35; prothoracic length, 3.20; anterior prothoracic width, 3.0; posterior prothoracic width, 2.80; widest prothoracic width 3.65; humeral width, 4.40; elytral length, 9.20. Paratypes male/female. Total length, 11.45–15.10/13.06–16.10; prothoracic length, 2.40–3.70/3.10– 3.90; anterior prothoracic width, 2.25–3.40/2.88–3.72; posterior prothoracic width, 1.95–3.20/2.70– 3.50; greatest prothoracic width 2.82–4.48/3.50–4.90; humeral width, 3.70–5.60/5.0–6.35; elytral length, 8.20–10.35/9.10–11.0.

Distribution

Mexico: Jalisco, Nayarit and Zacatecas.

Flower records

Tithonia tubiformis (Jacq.) Cass.

Remarks

The females of this species are very similar to O. sommeri , but the geographical distribution (only in southern of the Sierra Madre Occidental) and pubescent pattern on the elytra are useful to separate them. Also, this species can be distinguished from other known species by the labrum reduced with straight sides (rounded in O. sommeri ); elytra with wide dark area covering nearly all of the posterior half (males); and metatarsomere I longer than II–V together. Ochraethes nigroapicalis sp. nov. is the species of genus Ochraethes with the most evident sexual dimorphism.

Species delimitation analyses

The final matrix of COI includes 84 terminals (including two species of Tanyochraethes and four of Trichoxys ), 660 aligned characters and data of all morphotypes were obtained for each species ( Figs 3–4 ). The multiple delimitation methods (ABGD, bPTP and GMYC) consistently separate the new species and support some synonymies within Ochraethes . Most of the species currently recognized species were recovered as single MOTU (Molecular Operational Taxonomic Unit).

The ABGD method with initial and recursive partitions recovered different results (initial = 18 MOTUs, recursive = 19 and 18 MOTUs), however, the last recursive partition showed 18 MOTUs ( Fig. 5 ). In bPTP method, Maximum Likelihood and Bayesian methods were congruent with 18 MOTUs. Finally, the coalescence analysis performed under GMYC method obtained the same MOTUs under coalescent models with a confidence interval of 11–22; likelihood of null model = 519.4138; likelihood of GMYC model = 525.3721.

Nevertheless, Ochraethes brevicornis ( Chevrolat, 1860) with O. virescens ( Chevrolat, 1860) , O. octomaculata Chemsak & Noguera, 2001 with Tanyochraethes cinereolus Chemsak & Linsley, 1965 , O. obliquus ( Chevrolat, 1860) with O. zebratus Bates, 1885 , O. sommeri ( Chevrolat, 1835) with Trichoxys giesberti , O. viridiventris ( Chevrolat, 1860) with O. nigritus Bates, 1892 , and O. z-littera ( Chevrolat, 1860) with O. cristoforii ( Chevrolat, 1860) and O. litura Bates, 1885 were recovered as one MOTU respectively. On the other hand, O. sommeri comprises a major morphological variation of the genus, with different populations across Mexico. The coalescence analysis suggest that all populations belong to a single MOTU, except the populations from southwestern Puebla, Oaxaca, Chiapas and Tabasco ( Ochraethes confusus sp. nov.) and populations from northwestern Jalisco, southwestern Nayarit and Zacatecas ( Ochraethes nigroapicalis sp. nov.).

The maximum likelihood tree from IQ-TREE represents a first approximation about the phylogenetic relationships of Ochraethes , which recovered the genus as polyphyletic; however, a more comprehensive study (additional markers and taxa) about the evolutionary relationships of this group is needed.

Figures

Fig. 2. Ochraethes nigroapicalis sp. nov. A–D. Holotype, ♂ (EMEC). A. Habitus, dorsal. B. Habitus, ventral. C. Habitus, lateral. D. Frons. E. Paratype, ♂ (CNIN), ventral view of male genitalia. F. Paratype, ♀ (EMEC), habitus, dorsal.

Fig. 3. Pubescence variation on the elytra in Ochraethes Chevrolat, 1860. A–B. Ochraethes brevicornis (Chevrolat, 1860) (♀, ♂). C–E. O. cinereolus (Bates, 1892) comb. nov. (♂, ♂, ♀). F–I. O. obliquus (Chevrolat, 1860) (♂, ♂, ♀, ♀). J–N. O. sommeri (Chevrolat, 1835) (♂, ♂, ♂, ♀, ♀). O–S. O. viridiventris (Chevrolat, 1860) (♂, ♀, ♂, ♂, ♀). T–X. O. z-littera (Chevrolat, 1860) (♂, ♂, ♂, ♀, ♀).

Fig. 4.Head, frontal view of type species of Ochraethes. A. Ochraethes brevicornis (Chevrolat, 1860),♀. B. O. virescens (Chevrolat, 1860), ♂. C. O. cinereolus (Bates, 1892) comb. nov., ♀. D. O. octomaculata Chemsak & Noguera, 2001, ♂. E. O. obliquus (Chevrolat, 1860), ♂. F. O. zebratus Bates, 1885, ♀. G. O. sommeri (Chevrolat, 1835), ♂. H. O. circuliferus (Chevrolat, 1860) (= Ochraethes sommeri), ♀. I. Trichoxys giesberti Botero et al., 2019, ♀. J. O. viridiventris (Chevrolat, 1860), ♂. K. O. nigritus Bates, 1892 (= Ochraethes viridiventris), ♂. L. O. clerinus Bates, 1892, ♀. M. O. z-littera (Chevrolat, 1860), ♂. N. O. cristoforii (Chevrolat, 1860), ♂. O. O. litura Bates, 1885, ♀.

Fig. 5. Species delimitation in Ochraethes Chevrolat, 1860. Maximum likelihood tree inferred from COI in IQ TREE. The molecular operational taxonomic units (MOTU) are separated by colour bars. Abbreviations: ABGD = ast recursive analyses; bPTP = both Maximum likelihood and Bayesian analyses; GMYC = coalescence and yule analyses; MORP = morphology.