Platynectes maizuqii, Jiang & Zhao & Jia & Šťastný, 2023

Jiang, Zhuo-Yin, Zhao, Shuang, Jia, Feng-Long & Šťastný, Jaroslav, 2023, Two new species of Platynectes Régimbart, 1879 from China with notes on other Chinese members of the genus, including a key to species (Coleoptera: Dytiscidae: Agabinae), Zootaxa 5227 (4), pp. 401-425 : 403-404

Platynectes maizuqii sp. nov.

( Figs 1A, C–D , 12A )

Type locality. China, Guangdong Province, Shaoguan, Renhua County, Danxiashan Mt. , ca. 25.0347N, 113.7407E, 100 m.

Type material. Holotype ♂ ( SYSU), labelled: “ ŨAE ḂOiẌffiḩẇh / BDƜ / 25.0347N,113.7407E / 98.0 m, 20.ix.2021 / RDZƛ [p] // CHINA: Guangdong Province / Shaoguan , Renhua County / Danxiashan Mt. / 25.0347N, 113.7407E / 98.0 m, 20.ix.2021 / Zuqi Mai leg. [p] // HOLOTYPE / PLATYNECTES / maizuqii sp. nov. / Jiang, Jia & Šťastný det. 2022 [red label, p]” . Paratypes: 1 ♂, same label data as holotype ( SYSU); 2 ♀ , labelled: “ ŨAEBDƜ / 2008.5.23 / NJΦλ：AEṂÄ [p] // CHINA: Guangdong Province / Danxiashan Mt. / 23.v.2008 / Fenglong Jia leg. [p]” ( SYSU). All paratypes with the respective red printed label .

Description of holotype. Habitus ( Fig. 1A ) oblong-oval, with continuous outline, broadest before middle of elytral length, moderately convex. Dorsal surface slightly matt due to distinct reticulation.

Colouration. Head yellow, with black triangular spots on frons between eyes; pronotum black with anterior angles and lateral margins yellow, anterior margin and transverse medial band reddish-brown; elytra black with yellow transverse basal fascia and eight longitudinal vittae, sublaterally behind middle of elytral length and near apex with irregular yellow spots; appendages reddish-brown; ventral side black with reddish-brown spot on each side of abdominal ventrites II–IV.

Head. Moderately broad, width ca. 0.6× that of pronotum. Anterior margin of clypeus semicircular, with pair of sublateral foveae. Antenna with antennomeres long and slender. Eyes emarginate anterolaterally. Punctation double; several coarse setigerous punctures present in fronto-clypeal grooves and in depressions along inner margin of eyes; fine punctures distributed sparsely and irregularly on head surface, mainly at intersections of meshes. Reticulation deeply impressed consisting of heterogeneous, somewhat elongate, polygonal meshes; most meshes closed, usually with several micropunctures inside.

Pronotum. Transverse (width/length ratio = 3.5), broadest between posterior angles. Sides moderately curved, with distinct bead. Anterior margin nearly straight, posterior margin slightly sinuate. Punctation double, similar to that of head; rows of coarse setigerous punctures present along anterior margin and lateral parts of basal margin; fine punctures distributed irregularly on pronotal surface, mainly at intersections of reticulation. Reticulation similar to that of head, on disc meshes larger and less impressed, sometimes not closed, near sides becoming much smaller and more deeply impressed. Centre of disc with small indistinct longitudinal furrow.

Elytra. Base of elytra as broad as pronotal base; lateral margins of elytra moderately curved. Transverse yellow fascia present at base of elytra, interrupted only sublaterally. Eight yellow longitudinal vittae present on each elytron: vitta 1 almost continuous, vittae 2–7 formed by series of dots, vitta 8 interrupted medially, vitta 5 bifurcate anteriorly; vittae 1–5 and 8 beginning from transverse basal fascia and ending at apex, vittae 6 and 7 beginning slightly behind transverse basal fascia and ending at apex. Punctation double; coarse setigerous punctures present along vittae 1, 3, 5, 7 and lateral margins of elytra; fine punctures distributed irregularly over elytral surface, mainly at intersections of reticulation. Reticulation well impressed, similar to that of head and pronotum, meshes usually with several micropunctures inside, sometimes not closed.

Legs. Meso- and metafemora with tuft of spiniform setae along ventral margin of anteroapical angle. Pro- and mesotibia broadened, club shaped, densely punctured with spinigerous punctures over ventral surface. Metatibia with two lines of coarse spinigerous punctures on ventral surface. Pro- and mesotarsomeres 1–3 moderately broadened, with adhesive setae on ventral side; claws simple. Metatarsal claws subequal; anterior claw slightly shorter than posterior one. Surface of legs with distinct reticulation consisting of elongate meshes.

Ventral side. Anterior margin of prosternum sinuate, obtusely keeled medially. Prosternal process shortly lanceolate, in cross-section convex, with distinct lateral bead in basal half, apex pointed; surface with irregular sparse double punctation. Medial part of metaventrite without microsculpture, shiny, with sparse fine punctation; lateral parts of metaventrite (“metasternal wings”) tongue-shaped, slender, reaching lateral margins. Metacoxal lines distinct, well impressed, subparallel anteriorly, divergent posteriorly. Metacoxal plates covered with shallow transverse wrinkles; reticulation consisting of polygonal meshes, punctation consisting of sparse fine punctures. Conjoint posterior margin of metacoxal processes slightly concave. Abdominal reticulation consisting of elongate polygonal meshes, longitudinal on ventrite I, oblique on ventrite II and transverse on ventrites III–V; ventrites III–V additionally with numerous fine transverse wrinkles medially. Punctation double; ventrites III–V with setigerous punctures arranged sparsely in transverse line in medial part and with one coarser setigerous puncture presents in middle; fine punctures distributed sparsely and irregularly on ventrite surface. Abdominal ventrite VI with sublateral rugose area comprising nearly 10 deep longitudinal grooves on each side; reticulation present only baso-laterally; punctation double, coarse setigerous punctures present along posterior margin, fine punctures distributed densely on middle part.

Male genitalia. Median lobe of aedeagus in lateral view strongly curved; with distinct setae subapically along both ventral and dorsal margins; basal piece with distinct protuberance subapically on dorsal side; apical region moderately elongate, apex rounded ( Fig. 1C ). Parameres slender, with dense setae dorsally, with distinct subbasal tooth on ventral side ( Fig. 1D ).

Female. Identical to male in habitus. Meshes of dorsal surface reticulation more deeply impressed and longitudinally stretched, reticulation postero-laterally to eyes densely consists of elongate closed meshes, surface appearing more matt. Abdominal ventrite VI without deep longitudinal grooves sublaterally. Pro- and mesotibia less broadened; pro- and mesotarsomeres not broadened, without adhesive setae ventrally.

Variability. Sublaterally behind middle of elytral length sometimes without irregular yellow spots.

Measurements. TL: 6.3–6.5 mm (mean value: 6.4 ± 0.1 mm); holotype: 6.4 mm. TL-h: 5.7–5.9 mm (mean value: 5.8 ± 0.1 mm); holotype: 5.8 mm. MW: 3.8–4.0 mm (mean value: 3.9 ± 0.1 mm); holotype: 3.8 mm.

Differential diagnosis. The new species is similar to P. nanlingensis Šťastný. Some specimens of P. maizuqii sp. nov. with irregular yellow spots sublaterally behind middle of elytral length, but this is not stable. The two species can be reliably distinguished by the shape of the median lobe: apical region in lateral view almost of even width in P. maizuqii sp. nov., but slightly broadened in P. nanlingensis .

Collection details. The two male specimens were collected among crevices between stones in a rainwater ditch alongside a mountain road.

Etymology. The species is dedicated to its collector, Zu-qi Mai (SYSU), a specialist of water scavenger beetles ( Hydrophilidae ). The species name is a noun in the genitive singular.

Distribution. So far known only from the type locality in Danxiashan Mt., northern Guangdong, China ( Fig. 12A ).

Figures

FIGURE 1. Habitus and male genitalia of new species. (A, C–D) P. maizuqii sp. nov. (holotype ♂; Danxiashan, Guangdong); (B, E–F) P. pangu sp. nov. (holotype ♂; Huanglianshan, Yunnan). (A, B) habitus in dorsal view; (C, E) median lobe in lateral view; (D, F) paramere. Scale bar = 2.0 mm (A, B); Scale bars = 0.5 mm (C–F).

FIGURE 12. Maps of distribution of Platynectes species in China. (A) P. kashmiranus lemberki, P. maizuqii sp. nov., P. major and P. mazzoldii; (B) P. nanlingensis, P. pangu sp. nov. and P. rihai.