Rostrolatum curviceps, Constant & Pham, 2024

Constant, Jérôme & Pham, Hong Thai, 2024, Sixteen issid planthopper species in one day in Dong Son-Ky Thuong Nature Reserve in North Vietnam: Eight new species, one new genus and additional new records (Hemiptera: Fulgoromorpha: Issidae), European Journal of Taxonomy 919 (1), pp. 1-87 : 57-61

Rostrolatum curviceps sp. nov.

urn:lsid:zoobank.org:act:A2D342C3-2312-4072-953D-2E39ECE3291F

Figs 2C–D , 28–30

Diagnosis

Rostrolatum curviceps sp. nov. can be recognized by

(1) the elongate vertex, about 1.7 times as long in midline, as wide basally ( Fig. 28A );

(2) the posterior margin of the pygofer with a distinct angular projection in upper third ( Fig. 29A );

(3) the elongate, strongly recurved ventral processes of the aedeagus overlapping ventrally ( Fig. 29E– F, H ).

Differential diagnosis

The new species can be separated from R. separatum by its more elongate vertex (only 1.2 times as long in midline, as wide basally in R. separatum , as compared to 1.7 – ratio extrapolated from Zhang et al. 2020: pl. 25j), and a more developed, angularly lobous posterior projection along dorsal half of the posterior margin of the pygofer ( Zhang et al. 2020: fig. 133f) as opposed to a triangular projection in R. curviceps sp. nov.

Etymology

The species epithet derives from the Latin adjective ‘ curvus ’ meaning ‘curved’, and the Latin suffix ‘- ceps ’ meaning ‘headed’. It refers to the shape of the head of the new species in lateral view.

Type material

Holotype

VIETNAM • ♂ (dissected – Figs 2C–D , 28–29 ); Quang Ninh Province, Dong Son-Ky Thuong Nature Reserve ; 21°08′29″ N, 107°04′53″ E; 27 Aug. 2022; 550 m a.s.l.; secondary forest; GTI Project; J. Constant, J. Bresseel and L. Semeraro leg.; I.G.: 34.518; RBINS.

Paratypes

VIETNAM • 1 ♀; same collection data as for holotype; RBINS • 1 ♂ (dissected); Lang Son Province, Mau Son Summit ; 21°50′17″ N, 106°54′49″ E; 19–24Aug. 2022; J. Constant, J. Bresseel and L. Semeraro leg.; I.G.: 34.518; VNMN .

Description

MEASUREMENTS AND RATIOS. LT: ♂ (n = 2): 6.2 mm, ♀ (n = 1): 6.9 mm; LT/BB = 2.16; LTg/BTg = 2.34; LW/BW = 1.6; BV/LV = 0.58; LF/BF = 1.41.

HEAD ( Fig. 28A–D ). Narrower than thorax and elongate, with more than half of vertex length surpassing eyes. Vertex brown, curved anteroventrad in lateral view; shallowly concave basally, shortly convex at level of anterior margin of eyes, then grooved on remaining distal portion, about 1.7 times as long in midline as broad basally, with sides concave, converging towards narrowly rounded, paler apex; yellowish median carina in basal ¼; posterior margin carinate; lateral margins carinate, yellowish in basal portion and more elevated in distal half; posterior margin angularly concave. Frons slightly convex in cross-section, strongly curved cephalad at level of eyes in lateral view, widest just above curved frontoclypeal suture; lateral margins sinuate before process; brown more or less densely covered in minute yellowish points, darker on underside of cephalic process and with yellowish pustules along lateral margins; thin median yellowish carina more strongly marked on underside of process. Posterior side of head dark brown with yellowish median line. Genae brown with contrasted yellowish marking basoventrally and a smaller one under eye; strong carina parallel to anterior margin of eye; side of cephalic process brown punctured with yellowish, visible in dorsal view. Clypeus subtriangular, variegated yellowish brown with sides darker. Labium dark brown, elongate and narrow, with apical segment elongate, shorter than penultimate. Eyes subcircular (not emarginate), protruding laterally; ocelli absent. Antennae brown, rather short with scape ring-shaped and pedicel globular.

THORAX ( Fig. 28A, C–D ). Pronotum variegated yellowish brown, darker in middle of disc and with large black-brown marking on anterolateral portion (behind eye); about 0.66 times as long as mesonotum in midline; anterior margin carinate, strongly sinuate and strongly, roundly protruding anteriorly between eyes, with carinae extending down to ventral margin of paranotal lobes, sinuate on lobes; posterior margin weakly bisinuate; median carina obsolete anteriorly with impressed point on each side; rather large blunt, pale yellowish tubercles along anterior margin’s carina and on disc and lateral fields; paranotal lobes (lateral view) moderately broad, posterior to carina brown with pale yellowish tubercles, sometimes turning into short, blunt, longitudinal carinae along posterior margin, anterior to carina black-brown as behind head with transverse pale yellowish marking at mid-height. Mesonotum variegated yellowish brown, darker in middle portion; subtriangular with anterior margin finely carinate; obsolete median carina and two incomplete lateral carinae; disc smooth; some blunt, pale yellowish tubercles in lateral fields of mesonotum. Tegulae yellowish brown.

TEGMINA ( Figs 2C–D , 28A–C ). Mostly variegated olivaceous green with whitish markings; clavus rosy brown with large blackish patch, itself containing whitish area along claval suture; claval suture marked with a black line along most length; transverse whitish band at about basal ¼, from costal margin to claval suture; cross-veins usually paler than background; subcoriaceous with longitudinal veins moderately elevated, with A1-Pcu+A1 distinctly raised in distal portion, and with a dense reticulum of veinlets; shape elongate and convex with sides broadly rounded, about 2.3 times as long as broad; narrowly rounded apically; postclaval margin slightly notched at apex of clavus. Clavus closed, reaching about 3/5 of tegmen length. Venation: ScP+R moderately developed, forking into ScP+RA and RP; RP forking rather shortly after Sc+RA–RP fork; MP forking at about half of tegmen length; CuA not forked; Pcu fused with A1 at ¾ of clavus length; Pcu+A1 fused with CuP slightly before apex of clavus.

HIND WINGS ( Fig. 28E ). Brown with yellowish zone in CuP-Pcu-A1 lobe, venation slightly darker than background; wing broader than tegmen and deeply bilobed at CuP; costal margin sinuate; CuP-Pcu-A1 lobe about 1.5 times as wide as Sc-R-MP-CuA lobe, both lobes of same length and rounded apically; postclaval margin broadly rounded; A2 lobe brown, reduced and narrow. Venation: main veins present; ScP+R, MP and CuA running more or less parallel, slightly diverging towards apex, with numerous cross-veins; Pcu curved around basal third of wing towards CuP but not reaching the latter; A1 curved, more or less parallel to postclaval margin; CuP-Pcu-A1 lobe with numerous cross-veins; A2 vein obsolete.

LEGS ( Fig. 28A–D ). Elongate and slender, olivaceous with femora slightly darker than corresponding tibiae; pro- and mesofemora with more or less distinct pale ring at midlength; metafemora paler at base and apex; apex of spines of metatibiae and -tarsi black; metatibiae with 2 lateral teeth on distal third and 8 apical teeth; first metatarsomere elongate and slender, with strong spine at each side and row of 5 smaller spines in between ventrally along posterior margin; second metatarsomere short with one tooth at each side. Metatibiotarsal formula: (2) 8 / 7 / 2.

ABDOMEN ( Fig. 28B ). Dark brown.

MALE TERMINALIA. Pygofer (Py – Fig. 29A–D ) about 2.7 times as high as long at mid-height in lateral view, with anterior margin weakly concave and posterior margin oblique in dorsal ⅓ to posterior triangular projection (directed caudad), then more or less straight under projection, subparallel to anterior margin. Gonostyli (G – Fig. 29A–C ) (in lateral view) concave, elongate, about 2.4 times as long as high (without dorsal capitulum), projecting posteriorly to capitulum in distinct lobe rounded apically; capitulum (ca) strongly developed, with wide neck, directed dorsad, twisted with distal portion anteroposteriorly flattened, with apical hook directed mesocephalad and with lateral laminate projection in basal half curved lateroventrad, hook-shaped in caudal view. Aedeagus ( Fig. 29 E–J ) symmetrical, moderately curved dorsad (in lateral view); pair of elongate lateroventral processes (lvp) directed mesocephalad, evenly, strongly recurved and overlapping ventrally, reaching beyond anterior margin of periandrium; periandrium strongly developed, wider than remaining part of aedeagus; dorsal lobe of periandrium (dl) dorsoventrally flattened, tapering and with lateral lobe (ll) sinuate in distal portion, and with distal middle portion developed as a vertically protruding disc; phallus with elongate lateral shafts with inner margin indented subapically; ventral lobe of periandrium (vl) laminate, rather thin and tapering towards roundly acute apex. Anal tube (An – Fig. 29A–D ) dorsoventrally flattened, about as wide as long in midline, in dorsal view suboval with posterior margin deeply, roundly emarginate, the posterior angles projecting posteroventrad and narrowly rounded; lateral margin in basal portion, expanded into a moderately developed lobe curved ventrad; anal opening at about basal ⅓.

Biology

Rostrolatum curviceps sp. nov. was collected in August, on lower vegetation and bushes, in moist evergreen tropical forest at about 550 m in altitude ( Fig. 1B ) in Dong Son-Ky Thuong Nature Reserve, and in moist evergreen tropical mountain forest at about 1000 m in altitude ( Fig. 30B ) on Mount Mau Son.

Distribution

The species is currently recorded from Dong Son-Ky Thuong Nature Reserve, Quang Ninh Province and Mount Mau Son, Lang Son Province ( Fig. 30A ).

Figures

Fig. 2. Issidae Spinola, 1839 in nature in Dong Son-Ky Thuong Nature Reserve. A. Kodaianella mua sp. nov. B. Longieusarima lunulia Wang, Bourgoin & Zhang, 2017. C–D. Rostrolatum curviceps sp. nov. E. Fortunia sp., nymph. F. Hemisphaerius bresseeli sp. nov. G. Maculergithus luteomaculatus (Constant & Pham, 2016). H. Neogergithoides scapularis sp. nov.

Fig. 28. Rostrolatum curviceps sp. nov., dissected holotype, ♂ (RBINS). A. Habitus, dorsal view. B. Habitus, ventral view. C. Habitus, lateral view. D. Habitus, perpendicular view of frons. E. Right hind wing.

Fig. 29. Rostrolatum curviceps sp. nov., holotype, ♂ (RBINS), terminalia. A–D. Pygofer, anal tube and gonostyli. A. Lateral view. B. Caudal view. C. Laterocaudal view. D. Dorsal view. E–J. Aedeagus and connective. E. Left lateral view. F. Left ventrolateral view. G. Ventrocaudal view. H. Ventral view. I. Dorsal view. J. Anterodorsal view.Abbreviations: see Material and methods.

Fig. 30. A. Rostrolatum spp., distribution map. B. Habitat of R. curviceps sp. nov. on Mount Mau Son, 23 Aug. 2022.

Fig. 1. Dong Son-Ky Thuong Nature Reserve. A. Topographic map. B. Sampled habitat.