Macratria saccharum, Telnov, 2023

Telnov, Dmitry, 2023, Fourth contribution to the Macratriinae LeConte, 1862 of the Papuan Region and Wallacea (Coleoptera: Anthicidae) with descriptions of sixteen new species, Zootaxa 5361 (1), pp. 1-52 : 33-36

Macratria saccharum sp. nov.

urn:lsid:zoobank.org:act:772842F9-2EE4-4F20-82A0-C506F36EE097

( Figs 82–89 )

Type material designated. Holotype ♂ NME: INDONESIA E, New Guinea, Papua Prov., Bonggo 26 km SE, Toareng River , 02°25’15’’S 139°46’25’’E, 25 m, 28.III., river valley, from riverside vegetation [printed].

Paratypes 13 specimens. 9♂ ♀ NME & 4♂ ♀ DTC: same label as holotype.

Derivatio nominis. Named after Saccharum Linnaeus, a genus of grasses with several species native to New Guinea ecologically bound with this new species. Noun in apposition.

Measurements, holotype male, total body length about 2.8 mm; head length 0.6 mm, head width across compound eyes 0.55 mm, pronotal length 0.65 mm, maximum pronotal width 0.55 mm, elytral length 1.6 mm, combined maximum elytral width 0.7 mm. Selected male paratypes 2.6–2.8 mm, selected female paratypes 2.6–2.9 mm long.

Description. Male ( Figs 82–83 ). Dorsum and venter uniformly black to black-brown. Mouthparts including maxillary palpi, antennomeres 1–8, pro- and mesotarsi yellow, Antennomeres 9–11 dark brown with distal parts contrastingly yellow. Femora and tibiae brown, latter somewhat paler distally and basally. Basal metatarsomere brown, remaining metatarsomeres yellowish. Head slightly glossy dorsally, moderately glossy ventrally, nearly circular. Frons moderately narrow, about 0.8× as wide as dorsal eye length. Compound eye large, occupying whole lateral side of head beyond antennal insertion, moderately strongly protruding from lateral outline of head, about 4× as long as rounded, short tempus. Interfacetal setae moderately long, sparse. Head base broadly rounded. Frontoclypeal suture or impression not observed. Head dorsal punctures rather small, dense, moderately deep. Intervening spaces smooth, generally narrower than punctures, considerably less dense on vertex. Head dorsal setae greyish, appressed to somewhat subdecumbent, dense, not concealing dorsal surface of head. Tactile setae sparse, erect, not longer than ordinary setae, mainly arranged on head base. Antenna slender, slightly thickened at apex, not or hardly extending towards base of pronotum when directed posteriad. Basal antennomere elongate, about 1.3× as long as antennomere two. Antennomere three about 1.3× as long as antennomere two, about as long as antennomere four. Antennomeres 3–8 elongate, 9–10 widened distally. Terminal antennomere elongate, acutely pointed, twice as long as penultimate antennomere. Terminal maxillary palpomere shortly cultriform. Pronotum slightly glossy dorsally and on prothoracic hypomeron, flattened in dorsal aspect, broadly elliptical, hardly narrower than head across compound eyes. Anterior margin broad, rounded, medially truncate. Lateral margins constricted laterally posteriad. Dorsal pronotal punctures much larger and denser than those on head, deep. Intervening spaces smooth, distinctly narrower than punctures. Pronotal dorsal setation intermixed whitish and dirty yellowish, dense, appressed to slightly subdecumbent, not fully concealing dorsal sculpture of pronotum. Tactile setae sparse, erect, not longer than ordinary setae. Scutellar shield small, truncate at posterior margin. Elytron moderately elongate, subopaque, slightly narrows posteriad. Humerus broadly rounded. Postbasal transverse impression not indicated. Punctures on each elytron in anterior half arranged into five incomplete, poorly defined, flat rows. Intervening spaces between rows smooth to minutely punctate. Elytral setation greyish, moderately long, dense, directed posteriad, effectively concealing dorsal sculpture of elytron. Those setae in rows of punctures yellowish, directed strongly posteriad. Lateral humeral stria not shifted dorsad, not visible in dorsal view. Sutural stria complete, rather broad. Metathoracic wing fully developed. Legs moderately stout. Femur clavate. Tibial terminal spurs paired, at least those on foretibia serrate. Basal terminal metatarsomere longer than combined length of remaining metatarsomeres. All claws dentate at base. Male tergite VII subtruncate to shallowly, broadly emarginate at posterior margin ( Fig. 84 ). Male morphological sternite VII short and broad, subtruncate at posterior margin ( Fig. 85 ). Aedeagus ( Figs 86–87 ) long and slender, basale slightly longer than narrower apicale. Paramere wider in basal two thirds, strongly narrower in apical third, apically rounded. Median lobe deeply and narrowly cleft in apical part, appears monopartite.

Sexual dimorphism. Female externally similar to male, antennomeres 9–11 comparatively shorter, terminal antennomere about twice as long as penultimate antennomere. Female tergite VII subtruncate at posterior margin ( Fig. 88 ), morphological sternite VII broadly subtriangular, rounded at posterior margin ( Fig. 89 ).

Differential diagnosis. Macratria saccharum sp. nov. is a member of the pygmaea species-group (see Telnov 2011: 106 for the group definition) and differs from externally similar congeners in the shape of the aedeagus. The aedeagus of M. saccharum sp. nov. appears similar to that of M. distincticornis Pic, 1900 (West New Guinea: Onin Peninsula and Bird’s Neck Isthmus), but the paramere significantly widened medially and basally (the paramere slender in M. distincticornis ), and the male tergite VII very shallowly emarginate at posterior margin (broadly rounded in M. distincticornis ). The aedeagus, the subtruncate posterior margin of the male morphological sternite VII and the broadly emarginate posterior margin of the male tergite VII of M. saccharum sp. nov. appears closest to those of M. albertisi Pic, 1900 (southern lowlands of New Guinea and the Papuan Peninsula), but the paramere without arched fold in basal area (present in M. albertisi , delimiting the transparent, wing-like lateral extension of the paramere from its main “stem”) and the median lobe at base prolonged into two distinct, narrow and long prongs M. saccharum sp. nov. which are absent in M. albertisi .

Ecology. Collected on a hot, open riverbank from underside and inside of leaf sheaths of Saccharum sp. reed-like riverside vegetation.

Distribution. Northern lowlands, New Guinea.

Figures

FIGURES 82–83. Macratria saccharum sp. nov., holotype ♁. 82—Habitus, dorsal view; 83—Same, forebody and antennae, dorsal view [not to scale].

FIGURES 84–89. Macratria saccharum sp. nov. 84—Paratype ♁, tergite VII, dorsal view; 85—Same, morphological sternite VII, ventral view; 86—Same, aedeagus; 87—Same, aedeagus, apical portion; 88—Paratype ♀, tergite VII, dorsal view; 89— Same, morphological sternite VII, ventral view [not to scale].