Mauroniscus chilensis, Estrada & Solervicens, 2021

Estrada, Patricia & Solervicens, Jaime, 2021, Description of a new species of Mauroniscus Bourgeois, 1911 from Chile (Coleoptera: Mauroniscidae), Zootaxa 4915 (1), pp. 127-132 : 128-131

Mauroniscus chilensis n. sp.

(Figures 1,2)

Specimens examined: Holotype: Chile, Cordillera, R.N. Río Clarillo, 8/1/92. J. Solervicens. Eryngium paniculatum . Mauroniscus chilensis Estrada & Solervicens 2020 . Holotype deposited in IEUMCE, ♁.

Paratypes: Chile, Cordillera, R.N. Río Clarillo, 8/1/92. J. Solervicens. Eryngium paniculatum . Mauroniscus chilensis Estrada & Solervicens 2020 . 6 ♁ (IEUMCE). Chile, Cordillera, R.N. Río Clarillo, 8/1/92. J. Solervicens. Eryngium paniculatum . Mauroniscus chilensis Estrada & Solervicens 2020 . 3 ♀ (IEUMCE). Chile, Cordillera, R.N. Río Clarillo, 8/1/92. J. Solervicens. Eryngium paniculatum . Mauroniscus chilensis Estrada & Solervicens 2020 . 5 ♁, deposited in Museo Nacional de Historia Natural, Santiago, Chile (MNNC).

Diagnosis. Body oblong, with dense light pubescence on dorsal surface ( Fig.1a ). Antennae with eighth segment narrower than the adjacent antennomeres of flagellum ( Fig.1b ). Labrum with elongated tormae ( Fig. 1c ). Male ventrite VIII with spiculum relictum almost as long as the ventrite ( Fig. 2e ). Parameres like two flat and flexible laminae that surround the median lobe; tegminal arms thick, fused at base forming a short apodeme ( Fig. 2g, h ). Median lobe with two subapical lateral lobes, with five elongated spines on each side at the middle, and with middle part covered at rest by two lateral laminae; struts of median lobe about 0.4 times its total length, with widened and apparently articulated bases.

Description. Average body length 2.3 (range: 2.0-3.0 mm, n= 22), length: width ratio 3.4:1, sides slightly and gradually flared out back; punctuation moderately coarse, dense on the head, pronotum and elytra; pubescence dense, light yellowish, decumbent, and uniformly distributed on the dorsal surface; body black or dark-testaceous, antennae with 3 distal segments darker than the preceding antennomeres; legs orange ( Fig. 1b ).

Head. Black, oblique; including eyes approximately as wide as the anterior margin of pronotum (0.91:1); vertex convex, front sub-flat with a pair of moderately marked elongated lateral depressions, and a thin curved carina over antennal insertions; frontoclypeal region slightly prolonged and narrowed to the apex, frontoclypeal suture fine; labrum as wide as long in the dissected piece but apparently longer than wide in the preserved specimens with a rounded distal margin, tormae half the length of the labrum ( Fig 1c ); eyes large, oblong, their largest longitudinal diameter is almost half the width of the head; they are slightly convex, with medium-sized facets; short temples. Genae with a basal depression to accommodate the antennal base; mandibles moderately elongated and unidentate, prostheca extended along the mesal edge and provided with short bristles, especially at the apex where it forms a kind of brush ( Fig. 1d ); maxilla with short and narrow lacinia adjacent to the base of the galea, both with apical bristles ( Fig. 1e ); labium with ligula undivided, ligule surface with oblique rows of short bristles facing midline; last segment of the palp is long and wide with obliquely truncated apex ( Fig 1f ); antennae longer than the pronotum (1.4:1), with the last five segments moderately widened to form a club, and the eighth segment somewhat narrower than the adjacent ones ( Fig. 1b ); gula squared, slightly wider than long, slightly convex and straight gular sutures.

Thorax. Pronotum slightly wider than it is long (1.08:1), surface moderately convex in the middle and strongly convex on the sides, sub-straight longitudinally, base wider than apex (1.25:1) and narrower than humeral region (0.80:1), widest at middle, anterior and posterior margins very fine, lateral margin weakly marked or obsolete, anterior margin slightly concave at middle, posterior margin slightly convex, anterior angles rounded, basal angles moderately obtuse ( Fig. 1a ). Prosternum short in front of the coxa, transverse, thin and linear prosternal process; contiguous coxal cavities, widely open. Small mesoventrite, with narrow mesoventral process; open and subcontiguous coxal cavities. Broad, transverse metaventrite, markedly convex transverse and longitudinally, long discrimination, almost touching the anterior border, intercoxal space as wide as the base of the trochanter. Scutellum with sides slightly converging backwards, rounded posterior angle. Elytra 1.74:1 longer than it is wide and 1.8-2.6 times as long as pronotum, sides sub-parallel, slightly and gradually widening towards distal third, elytral disc slightly convex at center and markedly convex at sides, apex rounded, exposing the pygidium; epipleura narrow attenuating and terminating at ventrite III. Metendosternite: stalk longer than it is wide, anterior tendons short, approximated, lateral arms long, slender, extend anterolaterally ( Fig. 1g ). Legs: elongated and moderately hairy, with scarce and fine bristles in the ventral surface of tarsi, simple claws.

Abdomen. Female: ventrite VIII transverse, distal margin convex, spiculum ventrale four times longer than ventrite ( Fig. 2a ); spermathecal sclerite short, uniformly curved with conical extension to the center ( Fig. 2b ); pygidium semicircular, with rounded distal angles, basal margin with short apodemes ( Fig. 2c ). Male: ventrite VIII transverse, distal margin rounded, slightly prolonged at middle, spiculum relictum almost as long as the ventrite itself, basal angles laterally rounded ( Fig. 2d ); pygidium semicircular with short apodemes ( Fig 2e ); segment IX (spicular fork), with fine sternal arms and short apodeme, with central slightly sclerified piece, tergite membranous ( Fig. 2f ). Male genitalia: tegminal arms thick, curved and convergent medially, fused at base forming short apodeme ( Fig. 2g,h ); Median lobe with two subapical lateral lobes, with five elongated spines on each side at the middle, and with middle part covered at rest by two lateral laminae; struts of median lobe about 0.4 times its total length, with widened and apparently articulated bases ( Fig. 2h,i ).

Etymology. The specific name chilensis is a masculine adjective referring to Chile, the first species of Mauroniscus with Chilean distribution.

Distribution. CHILE: Metropolitan region, Cordillera Province, Río Clarillo National Park

Most of the specimens of Mauroniscus chilensis were collected on Eryngium paniculatum Cav. & Dombey ex F. Delaroche (Apiaceae) , probably in flowers. The latter is a native, perennial herbaceous plant, which is distributed throughout central Chile ( Rodriguez et al. 2018). Another specimen was collected under riparian vegetation using a pit-fall trap ( Solervicens 2014). Although the species has been collected in a single locality, it probably has a greater distribution in central Chile, similar to that of the host plant. The record of M. chilensis in the Central Chilean subregion ( Morrone 2015) corroborates Majer’s assumption (1995) about the presence of representatives of this genus in Chile.

Figures

FIGURE 1. Mauroniscus chilensis n. sp. a: habitus, scale 0.5 mm; b: antennae; c: labrum; d: mandible; e: maxilla; f: labium; g: metendosternite, scale 0.2 mm

FIGURE 2. Mauroniscus chilensis n. sp.: Female, a: ventrite VIII, scale 0.25 mm; b: spermathecal sclerite, scale 0.05 mm; c: pygidium, scale 0.25 mm; Male, d: ventrite VIII; e: pygidium; f: IX segment, scale 0.2 mm. Male genitalia, g: tegmen dorsal view; h: edeagus dorsal view; i: median lobe dorsal view, scale 0.2 mm