Brachycerocoris davidii Roca-Cusachs & Salini, 2021

Salini, S. & Roca-Cusachs, M., 2021, Review of the Oriental species of the genus Brachycerocoris Costa, 1863 (Hemiptera: Pentatomoidea: Pentatomidae: Podopinae s. l.) with description of two new species, Zootaxa 5040 (4), pp. 507-527 : 516-521

Brachycerocoris davidii Roca-Cusachs & Salini sp. nov.

( Figs. 4a–c ; Figs. 6a–f ; Figs. 7.4a–d )

urn:lsid:zoobank.org:act:1B917532-434C-40CF-B327-95ED15233BDC

Type locality. Philippines, Mindanao isl., Surigao del Sur, Tandag, San Miguel [8.959757 oN,126.0019 oE]

Material examined. Holotype: PHILIPPINES: Mindanao isl.: 1♀ [ MRC], ‘ Mindanao / Surigao del Sur / Tan- dag, San Miguel / v.2018. // HOLOTYPE / BRACHYCEROCORIS DAVIDII / sp. nov. / det. Roca-Cusachs & Salini, 2021 [p, red label]’. Holotype is mounted on triangular card point.

Differential diagnosis. Lateral abdominal tubercles considerably sharper and pronounced, and comparably, more brownish-gold and less silver-whitish pilosity on head and anterior pronotum than B. came1us and B. petrii sp. nov. Clearly separated from the other Asian species by having the scutellar tubercle extremely protruding (height of central scutellar tubercle about two times as long as wide).

Description. Colouration, Integument & vestiture. ( Figs. 4a–c ) General dorsal colouration blackish brown, with portion of corium, beneath scutellum, transparent and membrane black.Surface with coarse, deep punctures, nearly pit-like and covered with a velvety mat of short, setae; setae of dorsum of head, pronotum, anterior portion of scutellum and exposed portion of corium (at rest) brown and slightly shiny; antennae with sparse, semi erect, golden setae; setae of posterior portion of scutellum brownish gold.

Ventrally concolourous to dorsum ( Fig. 4c ), including legs, with the exception of a moderate sized kidneyshaped spot behind the eye, base of antennal segments IV and V, a small round spot at the distal end (on dorsal side) of each fore, mid and hind tibiae, tarsi of all legs, brownish red. Labium dark brown to black. Spiracular outline, black. Peritreme and evaporatorium and apical half of claws, black. Ventrally, including legs,covered with a velvety mat of short setae; tarsi devoid of mat of setae rather with short, sparse, semi erect, golden setae; exposed portion of genital capsule including the dorsal and ventral rim with mat of short, setae; female genitalia with valvifers VIII and IX, laterotergite VIII and IX including abdominal segment X with mat of short setae. Ventral side with deep, coarse pit-like punctures.

Structure. Head ( Figs. 4 & 6 ; Fig. 7.4a ) together with anterior half of pronotum strongly declivous, nearly perpendicular to body axis; head nearly as long as width including eyes, apex truncate, lateral margin strongly concave, ends in a quadrangular denticle subapically; dorsum of head convex with two distinct tubercles medially (mt), one on each mandibular plates and a nearly indistinct; small, ridge-like tubercle on clypeus, a moderately large tubercle towards base of head disc medially on an imaginary line connecting eyes. Mandibular plates nearly of uniform width throughout, apical margin with shallow incision, meeting in front of clypeus; clypeus narrowed towards apex and closed apically. Antennae 5-segmented, stout. Length of antennal segments: II<I<III<IV<V; antennal segment I geniculate, thickened medially and narrowed towards both ends; antennal segment II the shortest, slender; antennal segments III–IV stout and cylindrical; segment V the longest, thick and club-shaped; base of first antennal segment housed on a groove or pouch on genae. Bucculae with 1+1 short tubercle subapically or anteriorly, bucculae rounded posteriorly, nearly as long as first labial segment. Labium surpassing metacoxae (thanatosis position). Eyes short and rounded, posterior half accommodated in a groove on anterior margin of propleuron. Head posteriad of eyes surrounded by anterior pronotal margin.

Pronotum ( Figs. 4a–b ). Anterior pronotal margin deeply, arcuately concave, accommodating posterior end of head behind eyes; anterolateral angles rectangular bearing a short, blunt tooth, directed laterally; anterolateral margin obliquely straight interrupted with 1–2 short, blunt tubercle. Humeri rounded, globose. Anterior half of pronotal disc strongly declivous, medially with a large tubercle, apex of which rounded; 1+1 shorter tubercles developed on pronotal cicatrices anteriorly; one groove on lateral area of pronotum in front of humeri; posterior half of pronotal disc medially with five longitudinal ridges (1+ 1 in each side and central); Central and lateral ridges contiguous to central with anteriorly 1+1 short tubercle. Posterior margin of pronotum slightly concave; posterolateral angles angular, blunt.

Scutellum ( Figs. 4a–b ) Broad and subtriangular, nearly as long as broad at base. Base of scutellum medially with a short, elevated triangle possessing a very large tubercle (much longer than widein lateral view), apex of which arcuately rounded; outer margin of tubercle formed by a pair of ridges possessing a series of wide, triangular denticles, ridges medially connected by a narrow groove. Lateral margins of elevated triangular region with a row of pit-like structures, converging towards the apex of triangular region; apical half of scutellum medially with a moderately large tubercle, elevated at the same level than the “elevated triangular region”, beyond which troughlike towards the scutellar apex; scutellar apex broadly rounded, much surpassing apex of corium.

Hemelytra. Clavus narrow, elongate triangular. Clavus and an elongate triangular region from distal end of corium transparent. Corium laterally slightly arcuate; anterodistal angles narrowly rounded apically, much surpassing apex of scutellum. Part of corium (longitudinal half) and membrane (basal portion) covered by scutellum while resting. Membrane black, translucent, broadly rounded apically, reaches but usually not extending beyond apex of abdomen. Membrane bearing 7–8 simple veins, without reticulate venation.

Thoracic pleuron and sternum. All coxae placed close to each other, leaving only narrow space for labium; prosternum with deep groove to receive posterobasal portion of bucculae. Anterior margin of propleura with two grooves to accommodate the base of the genae and posterior half of eyes ( Fig. 6c ) respectively. Thoracic sternites with median, longitudinal groove on which labium rests. Ostiole narrowly elongate, accompanied with short, elevated circular disc-like peritreme. Evaporatorium short ( Fig. 6d ; Figs. 7.4b–c ), with prominent wrinkles, extending upto middle of metapleural width. Connexivum narrowly exposed laterally. Metathoracic spiracle long, sometimes only partially visible in ventral view as the thick mat of hairs overgrown ventrally on thoracic pleura.

Legs. Short, stout, all femora unarmed; profemora ventrally with longitudinal groove accommodating foretibiae; meso and metafemora cylindrical and rounded in cross section. All tibiae slightly slender than respective femora, cylindrical and rounded in cross section. All tarsi with segment II the shortest, III the longest with well-developed tarsal claws and pulvulli; all tarsal segments dorsally regularly rounded, not grooved.

Pregenital abdomen. Ventrite III and IV medially with shallow groove accommodating labial apex, remaining ventrites (ventrite V–VII) medially with concolour, glabrous patch of variable shapes( Fig. 6e ). Ventrites III–VII laterally with a pair of trichobothria mesad to spiracles. Posterolateral angles of ventrites III–VII with protruding, rounded tubercles.

Male unknown.

External female genitalia ( Fig. 6f ; Fig. 7.4d ). Terminalia. Valvifers VIII convex, subtriangular with mesial margins straight, with saw-tooth appearance (tooth blunt), posterior margins nearly straight, inner posterior angles rounded, centrolaterally with a shallow depression. Valvifers IX very small, hood-like, inwardly directed and connected to a pair of narrow finger-like plates, abdominal segment X subrectangular. Laterotergite IX large plate-like, partially embedded in the body cavity, exposed portion elongate, longer than broad, broadest medially, anterior half sharply narrowing beyond middle region. Laterotergite VIII joined medially, each laterotergite VIII with a projected caudally round tubercle; laterotergites IX, valvifers IX and abdominal segment X lay in the trapezoidal anterior rim of laterotergite VIII.

Measurements (in mm). Female (n = 1); Body length 8.5; head: length 2.1, width (including eyes) 2.2, interocular width 1.4; pronotum: length 2.9, width (including humeri) 4.3; scutellum: length 4.2, width (at basal angles) 4.1; height of scutellar tubercle: 2.1.

Remarks. This species is very distinct in having the distinctly large tubercle (much longer than wide in lateral view), apex of which arcuately rounded.

Etymology. The new species is kindly dedicated to our colleague and friend David A. Rider (North Dakota State University, Fargo, USA) for his valuable contribution to the taxonomy of Pentatomidae and also for helping the authors on numerous occasions. The gender of the genus Brachycercoris was not stated in the original description by Costa (1863), hence treated as masculine according to the Article 30.2.4 of ICZN. The species group name is noun in genitive case as per the Article 31.1.2 of ICZN and is masculine.

Bionomics. Unknown.

Distribution. Philippines [Mindanao]

Conclusion. The genus Brachycerocoris is represented by seven species including the two new species, viz., B. petrii Salini & Roca-Cusachs sp. nov. and B. davidii Roca-Cusachs & Salini sp. nov. described in this paper. Of these, three are from African region and the remaining four are from the Asian region. Among the Asian species, B. camelus , B. dromedarius and B. petrii Salini & Roca-Cusachs sp. nov. closely resemble one another in external morphology but they can be easily distinguished by the male genitalia, especially the shape of dorsal and ventral rim of genital capsule and shape of paramere. Schaefer (1997) recorded B. camelus for the first time from India, the only known species from India so far (before the addition of B. petrii Salini & Roca-Cusachs sp. nov. by this paper). B. camelus was originally described from China.Though Schaefer (1997) pointed out some differences in the specimens collected from India, the samples were still identified as B. camelus probably due to the non examination of male genitalia. In this paper, we could examine the male genitalia of the specimens collected from southern part of India (as of now the distribution of Brachycerocoris spp. is restricted to southern part of India) and lead to the description of B. petrii Salini & Roca-Cusachs sp. nov. Therefore, we presume that the close similarity in external morphology of B. camelus with B. petrii Salini & Roca-Cusachs sp. nov. might have lead to the misidentification of B. petrii Salini & Roca-Cusachs sp. nov. as B. camelus by earlier researchers ( Chatterjee 1934, Schaefer 1997, Azim 2011, Salini & Viraktamath 2015) as the male genitalia structures were not examined during their study. Moreover, the members of this genus were known to feed on host plants such as Canthium didymium C. F. Gaertn (Rubiaceae) , Zizyphus oenoplia (L.) Miller ( Rhamnaceae ) and Pterolobium hexapetalum (Roth) Santapau & Wagh. (Fabaceae) , but the report of host plant, Vitex trifolia L. ( Lamiaceae ) (in this paper) is an addition to the existing host list.

Figures

FIGURE 4. Habitus of Brachycerocoris davidii sp. nov. a, Habitus (dorsal); b, Habitus (lateral); c, Habitus (ventral). Lettering: mt–mandibular plate tubercle. Scale bar equals 1 mm.

FIGURE 6. Details of Brachycerocoris davidii sp. nov. a, head (dorsal);b, head (ventral);c, head (lateral); d, external scent efferent system; e, detail of pregenital abdomen, concolourous glabrous patches of variable size; f, female genital plates. Scale bar equals 1 mm.

FIGURE 7. SEM photographs: 1, Brachycerocoris camelus Costa; 2, Brachycerocoris petrii sp. nov.; 3, Brachycerocoris dromedarius (Vollenhoven); 4, Brachycerocoris davidii sp. nov. (a, head; b, external peritreme and evaporatoria; c, Detail of peritreme; d, female terminalia with deligned profile (yellow) for the left valvifers. Brachycerocoris camelus (7.1a–d) carries the scale bar and the numbering for all the serial photographs.