Plistonax inopinatus Lane, 1960

Silva Júnior, José O., Haseyama, Kirstern L. F. & Souza, Diego de S., 2021, Phylogenetic approach redefines Plistonax (Coleoptera, Cerambycidae, Lamiinae) with new combinations and a new genus of flat-faced long-horned beetles, Organisms Diversity & Evolution (New York, N. Y.) 21 (2), pp. 491-520 : 512-513

Plistonax inopinatus Lane, 1960 ( Fig. 15a, b, c, d, e, f, g )

Plistonax inopinatus Lane (1960): 47 , fig. 1; Zajciw (1972): 66 (distr.); Zajciw (1974): 77 (distr.); Monné and Magno (1992): 719, fig. 4 (rev.); Monné (2005): 199 (cat); Monné et al. (2010): 246 (distr.); Monné et al. (2012b): 48 (distr.); Monné et al. (2016): 21 (distr.); Monné and Monné (2017): 234 (distr.); Monteiro et al. (2020): 170 (distr.); Monné (2021) (cat).

Type-locality: holotype (male) – Brazil, Santa Catarina, Corupá ( AMNH) .

Diagnosis. Males with tubercles on inner surface of antenommeres VI–XI ( Fig. 2e ). Pronotum with sparse white setae, without median-longitudinal black bands ( Fig. 3c ).

Redescription. Male (♂) ( Fig. 15a–b ). General surface covered with decumbent light-brown setae, with distinct sparse white setae on frons, antenna, pronotum, legs and elytra. Head. Large punctures. Gena of little larger length than lower ocular lobe. Antenna. Scape with two dorsal dark-brown stains. Pedicel about 1/3 length of scape; antennomere III about 1.3 length of scape; antennomere IV subequal to scape; following antennomeres gradually decreasing in length, except antennomere XI, longer than X. Antennomeres V–XI each with one dark-brown stain subapical, intercalated by light-brown stains. Distinct erect setae on antennomeres I–VII; curly black setae on antennomeres IX– XI. Antenna reaching elytral apex at antennomere IX.

Prothorax. Pronotum entirely covered by brown setae, with short lateral tubercle; median tubercle slightly elevated. Prosternal process with lateral margin distinctily convex.

Mesothorax. Scutellum mostly covered by dark-brown setae, with a median-longitudinal yellowish band. Mesoventral process width smaller than diameter of mesocoxa; one pair of antero-lateral tubercles little distinct. Elytra. Median-basal crest starting from base, reaching near elytral slope, curved and with small ridges on anterior region. White stain covering mid-basal portion until near elytral apex, narrower at post-median region; one pair of post-median black Y-shaped stains; black stains on elytral slope forming zigzag between margins and elytral suture; margin with whitish stain. Internal semierect seta in punctures white, short and thick, strongly expanded towards apex, with near sulci each other ( Fig. 15g ). Elytral apex rounded. Legs. Femora with dark-brown stains. Tibiae slightly expanded towards apex, with two dark-brown stains, intercalated by stains formed by grayish and light-brown setae. Tarsomerus I covered by light-brown setae, tarsomeres II–V mainly with dark-brown setae. Abdomen. Covered entirely with white setae, sparser in segment V, except by glabrous lateral areas in segments I–IV; segment V with two light-brown stains posteriorly. Male terminalia ( Fig. 16a–f ). Tegmen ( Fig. 16a ). Ringed part strongly convex, with anterior region strongly sclerotized in both margins; posterior region membranous; apex rounded, with median proeminence. Paramere with uniform sclerotization, narrowed towards apex; basal region expanded laterally, with row of short setae; apex entirely covered by long setae; remaining surface with short and sparse setae. Endophallus ( Fig. 16b, c ). Median lobe strongly curved in lateral view, with dorsal lobe indistinguishable; ventral lobe entirely sclerotized, stronger at apex and lateral margins; apex slightly narrowed, with median deep invagination. Median strut membranous, smooth, with apex rounded. Internal sac with one pair of curved sclerotized structures anteriorly; one elongated sclerotized structure posteriorly, bifurcated in two rounded parts. Ventral arc ( Fig. 16d ). Membranous, with stem strongly curved at apex, wider at base of stem. Tergites ( Fig. 16e, f ). Tergites VII and VIII both entirely sclerotized, covered with short setae posteriorly, with apex rounded. Tergite VII subequal in length and width, with base rounded. Tergite VIII wider than longer, with base slightly concave, with membranous apophysis.

Female (♀) ( Fig. 15c–d ). Differs from male in the following: antenna without tubercles on inner surface, without curly black setae on antennomeres IX–XI; antenna reaching elytral apex at antennomere XI.

Variation. Antero-lateral tubercles on mesoventral process may be absent; general coverage of setae of scutellum may be light-brown; pattern of elytral stains may vary considerably, except the pair of Y-shaped stains; a pair of transversal black stains on anterior region of elytra may be present rarely (as in P. albolinitus ); the zigzag-shaped stain on elytral slope may be inconspicuous or absent.

Measurements (mm). Total length (11.8–18.1); elytral length (8.3–12.9); pronotum length (2.4–3.7); umeral width (4.7–7.6); pronotum width (3.6–5.8).

Distribution. Brazil [Bahia, Espírito Santo, Minas Gerais, Paraná, Rio de Janeiro, Santa Catarina, São Paulo] (Fig. S4c).

Remarks. Species similar to P. albolinitus . In the original description, Lane (1960) highlighted the presence of sparse white setae occurring on the head, antenna, pronotum, elytra, and legs of P. inopinatus , contrasting with P. albolinitus . In this work, we ascertained that these setae are present in both species, occurring in greater numbers in P. inopinatus , in which they are also more contrasting with the general pubescence. Lane (1960) detailed only the locations of the type series from the state of Santa Catarina. He listed a broad geographical range for the species, from southern to southeast Brazil (state of Santa Catarina to state of Espírito Santo), possibly implying that he had specimens from Paraná, Rio de Janeiro, and São Paulo, the Brazilian states within the two extremes described by the author. Later, specimens were recorded from the states of Espírito Santo, Rio de Janeiro, and São Paulo ( Monné and Magno 1992), but no specimen from the state of Paraná.

Figures

Fig. 15 Plistonax inopinatus (a– g): a male’s dorsal habitus; b male’s ventral habitus; c female’s dorsal habitus (paratype); d fe- male’s ventral habitus (paratype); e lateral habitus; f head (anterior view); g semierect seta of the elytral punctures, character state 28:0 (thick), micrograph (from left to right, base and apex; zoom 1500×). P. rafaeli (holotype) (h– l): h male’s dorsal habitus; i male’s ventral habitus; j lateral habitus; k head (anterior view); l semierect seta of the elytral punc- tures, character state 28:1 (slen- der), micrograph (from left to right, base and apex; zoom 900×). Scale bars: 5 mm, except figures f, k (1 mm), g, and l (25 μm)

Fig. 2 Character photographs: a 2:0 frons with small punctures (anterior view, Aegomorphus jaspideus). b 2:1 frons with large punctures (anterior view, A. travassosi). c 21:0 mesoventral process with antero-lateral tuber- cles slightly elevated (lateral view, Plistonax albolinitus). d 21:1 mesoventral process with antero-lateral tubercles very ele- vated (lateral view, Acanthoderes (Acanthoderes) daviesii). e 4:1 male’s antennomeres VI–XI with tubercles in the inner surface and 11:1 male’s antennomeres IX–XI with black setae in the inner sur- face (lateral view, male of P. albolinitus). f 6:1 antennomere III with darker stain near apex, 7:1 antennomere III with darker stain near base, 8:1 antennomere IV with darker stain near base, 9:0 antennomeres IV–XI with darker stain near apex in subapical posi- tion, and 10:1 antennomeres III– VII with erect setae in the inner surface (dorsal view, P. rafaeli). g 9:1 antennomeres IV–XI with darker stain near apex in apical position (dorsal view, P. insolitus). White dashed lines highlight the character states 2:0 and 2:1; blue arrows highlight the character states 6:1, 7:1, 8:1, 9:0, and 9:1; red arrows highlight the character state 10:1. Scale bars: 1 mm

Fig. 3 Character photographs: a 12:0 pronotum with punctures mainly in the anterior and posterior margins, rarely in the central region (dorsal view, Acanthoderes (Acanthoderes) daviesii). b 12:1 pronotum with punctures distributed uniformly, 13:0 pronotum with small punctures, 17:0 pronotum without median-longitudinal ridge (dorsal view, Ateralphus dejeani). c 13:1 pronotum with large punctures, 17:1 pronotum with median- longitudinal ridge, and 18:1 pronotum with sparse white setae (dorsal view, Plistonax inopinatus). d 30:1 femora with sparse white setae and 32:1 male’s protarsus with fringes of black setae (dorsal view, male of P. inopinatus). e 31:0 metatibia with darker stain near the apex in subapical position (lateral view, P. inopinatus). f 31:1 metatibia with darker stain near the apex in apical position (dorsal view, P. insolitus). Red arrow high- lights the character state 17:1; blue arrows highlight the charac- ter states 31:0 and 31:1. Scale bars: 1 mm

Fig. 16 Male terminalia: Plistonax inopinatus (a–f): a tegmen (ventral view); b endophallus (ventral view); c endophallus (lateral view); d ventral arc (ventral view); e tergite VII (dorsal view); f tergite VIII (dorsal view). P. rafaeli (g–l): g tegmen (ventral view); h endophallus (ventral view); i endophallus (lateral view); j ventral arc (ventral view); k tergite VII (dorsal view); l tergite VIII (dorsal view). Points and gray shapes represent sclerotized structures. Scale bars: 0.5 mm