Keosarima Constant, 2025

Constant, Jérôme & Pham, Hong Thai, 2025, Keosarima gen. nov., a new genus in the planthopper tribe Sarimini from Indochina (Hemiptera: Fulgoromorpha: Issidae), European Journal of Taxonomy 1007, pp. 35-56 : 37-40

Genus Keosarima Constant gen. nov.

urn:lsid:zoobank.org:act:DC3A4382-03F6-4F40-A217-D43928DDB17A

Type species

Keosarima armillata Constant gen. et sp. nov. by present designation.

Diagnosis

The genus Keosarima gen. nov. can be differentiated from the other genera of Sarimini by the following combination of characters:

(1) the vertex twice as wide as long in dorsal view;

(2) the frons with obsolete peridiscal carinae and with complete, distinct median carina prolongated at least along basal portion of clypeus;

(3) the tegmina elongate, about 2.2 × as long as wide, with distinct lateral hump slightly before basal ⅓ hiding costal margin in dorsal aspect, and with distinct epipleuron;

(4) the vein ScP of the tegmen long, rather weakly curved and reaching margin of tegmen around distal 1 / 5 of tegmen length;

(5) the first fork of MP and the first fork of CuA at about the same level (fork of CuA slightly more basal), around halflength of tegmen;

(6) the anal tube strongly elongate, dorsoventrally flattened, and oblong, moderately narrow in dorsal view;

(7) the massive gonostyli, with capitulum elongate, strongly projecting anterodorsad and with poorly distinct neck, and with anterodorsal margin moderately rounded;

(8) the aedeagus (sensu stricto) with a single pair of elongate, sinuate, ribbon-like, lateroventral processes arising at about distal ⅓, and with the laterodorsal process of the periandrium bearing an apical hook directed dorsad, and an elongate shaft directed cephalad.

Differential diagnosis

The most similar genus is Tetrica Stål, 1866 , which also shows a complete, distinct median carina of the frons, and a median carina on the clypeus (see illustrations of the holotype of the type species, Tetrica fusca Stål, 1970 in Gnezdilov et al. 2015: figs 20–23). However, Keosarima Constant gen. nov. can be separated from the latter by the tegmina more elongate, about 2.2 × as long as wide (1.8 × in Tetrica ), with its rounded angle of the costal margin placed more basally, before midlength (around midlength in Tetrica ), and by the hind wings with lobe CuP-Pcu-A1 without a closed cell (with a large, closed cell in Tetrica ).

Keosarima gen. nov. also shows morphological similarities with the genera Parallelissus Meng, Qin & Wang, 2020 (illustrations in Zhang et al. 2020: figs 182–183; Constant & Pham 2024a: figs 33–34) and Duplexissus Wang, Zhang & Bourgoin, 2019 (illustrations in Wang et al. 2019: figs 12–22), which also possess an elongate shaft directed cephalad on the periandrium. However, in both latter genera, the median carina of the frons doesn’t reach the ventral margin of the frons and does not extend to the clypeus. Parallelissus furthermore differs from Keosarima by the hind wings with vein Pcu furcating distally (not furcate in Keosarima ), and the male genitalia with gonostyli showing a very elongate neck (neck very short in Keosarima ). Duplexissus also differs from Keosarima by a less elongate anal tube (2.4 × as long as wide vs at least 3.0 × in Keosarima ), a strongly rounded anterodorsal margin of the gonostyli (moderately rounded in Keosarima ), and a periandrium with laterodorsal processes lacking an apical hook (strong apical hook in Keosarima ), but with distinctly dentate dorsal margin of the shaft of the periandrium (shaft smooth in Keosarima ).

Etymology

The genus name is formed from the combination of ‘Keo’, for ‘Keo Seima’, the Wildlife Sanctuary where the new genus was discovered, and ‘ Sarima ’, the type genus of the tribe Sarimini . Gender feminine.

Description

BODY. Medium sized (around 5.0–6.0 mm), very convex, moderately elongate, rather robust-bodied.

COLOUR. Mostly brown with paler markings on frons. Live specimens often more or less covered in golden brown powdery wax.

HEAD. Vertex distinctly broader than long in midline (about 2.0 ×), weakly concave with obsolete median carina; anterior margin forming widely obtuse angle, posterior one rather deeply concave, lateral ones sinuate; all margins moderately carinate. Frons weakly convex, narrowly visible (median carina distinct) from above, about 1.2 × as wide as long in midline, smooth with distinct complete median carina, and obsolete peridiscal carina; row of paler tubercles along margins; maximum breadth slightly under level of antennae; dorsal margin weakly concave. Anteroventral angle of genae not projecting anteriad. Ocelli present, under eye. Clypeus triangular, convex, smooth, with distinct median carina (stronger in basal portion). Labium with last segment longer than broad, about as long as penultimate. Antennae with scape short, ring-shaped, and bulbous pedicel.

THORAX. Pronotum subtriangular, projecting anteriorly in blunt straight angle, about 0.6 × as long in midline, as mesonotum; smooth with anterior margin carinate and pair of impressed points on each side of paler median line; lateral fields very narrow behind eyes; paranotal lobes with posteroventral angle rounded, sometimes with some tubercles. Mesonotum subtriangular with posterolateral margins slightly incurved, smooth, weakly convex with shallow depression before scutellum; incomplete, rather distinct, median and sublateral carinae.

TEGMINA. Distinctly convex, elongate, about 2.2 × as long as wide, with longitudinal veins elevated; costal margin forming broadly rounded angle at basal 2 /5; apical margin rounded; distinct lateral hump including vein ScP+RA slightly before basal ¼, hiding costal margin in dorsal aspect; costal margin hidden by vein RP in distal half, in dorsal view; distinct epipleuron; clavus closed, reaching 4 /5 of tegmen length. Venation: ScP+R rather short; ScP+RA long, reaching external margin of tegmen around distal 1 /5 of tegmen length; RP unforked, long and weakly curved; first fork of MP slightly before midlength of tegmen, MP1 with two terminales; first fork of CuA at about same level (slightly more basal), around halflength of tegmen; Pcu and A1 fused slightly beyond halflength of clavus, Pcu+A1 reaching apex of clavus; A1-Pcu+A1 strongly elevated, and slightly sinuate in dorsal aspect; numerous cross-veins on all surface of tegmen.

HIND WINGS. Well developed, with three distinct lobes ( Sarimini type) more or less equal in width; mostly brown. Venation: ScP+R and CuA furcate; MP simple, sinuate; second branch of CuA fused distally with CuP; Pcu and A1 fused on basal half, Pcu unforked and A2 simple; one transverse vein between second branch of ScP+R and MP, and between MP and first branch of CuA.

LEGS. Moderately elongate and slender, with pro- and mesofemora and pro- and mesotibiae slightly flattened dorsoventrally, tibiae more slender than corresponding femora; posteroventral margin of pro- and mesofemora with row of minute teeth; pro- and mesotarsi rather elongate. Metatibiae with two lateral spines in distal half and six apical spines. Metatarsi moderately short with first segment about as long as combined length of remaining segments. First metatarsomere with two latero-apical and six intermediate spines arranged in arc. Metatibiotarsal formula: (2) 6/ 8–9 / 2.

Male terminalia

Pygofer short, about 2.2 × as high as long at midheight in lateral view, with posterior margin broadly rounded in lateral view; in caudal view suboval, 1.4 × as high as wide. Gonostyli massive, moderately convex, subtriangular in lateral aspect with posterior and anterodorsal margins distinctly rounded; capitulum elongate, rather strongly projecting dorsad and with poorly distinct neck, curved anterodorsad and more or less evenly tapering towards apex in lateral view, with basilateral laminate process directed lateroventrad in caudal view. Anal tube strongly elongate, dorsoventrally flattened, and oblong, moderately narrow in dorsal view, about 3.0–3.4 × as long as wide in dorsal view and with anal opening in basal ¼; in lateral view, downcurved. Aedeagus symmetrical, rather strongly curved posterodorsad in lateral view. Ventral lobe of periandrium laminate, spatulate. Dorsal lobe of periandrium laminate, elongate, spatulate; laterodorsal processes of periandrium arising lateroventrally from middle portion of dorsal lobe, curved posterodorsad with apical hook directed dorsad, and moderately upcurved, elongate shaft directed cephalad. Aedeagus (sensu stricto) surpassing dorsal and ventral lobes of periandrium, bifid, with distal portion dilated, with single pair of elongate, sinuate, ribbon-like, lateroventral processes arising at about distal ⅓.

Distribution

Cambodia: Mondulkiri Province; Vietnam: Gia Lai Province.

Species included

Keosarima armillata Constant gen. et sp. nov.

Keosarima konkakinha gen. et sp. nov.