Toxidium ultimum, Groll, 2025

Toxidium ultimum sp. nov.

urn:lsid:zoobank.org:act:2B63D970-44EE-48E9-B41D-43F93E89373E

Figs 1A–B, E–F View Fig , 89–92 View Fig View Fig View Fig View Fig , 94A–B View Fig

Diagnosis

Body length: 1.56–1.70 mm. Dark brown, elytra apex yellow-ochreous. Sutural striae extending from apex to approximately 0.84 of the elytral sutural length. Metaventrite I with few coarse punctures next to submesocoxal lines. Abdominal ventrite I with imbricate microsculpture. Parameres with poorly sclerotized lobe medially. Sclerite if internal sac D-shaped. Distal gonocoxite slightly fusiform. Gonostylus elongate.

Etymology

The species epithet is a Latin word meaning ‘the last one’, referring both to it being the last species described in this manuscript and the final specimen collected and dissected for this project.

Material examined

Holotype

BRAZIL • ♂ *; Minas Gerais, Viçosa, UFV, Vila Gianetti ; 3 Dec. 2022; E. von Groll leg.; “/ Em Inonotus sp. ( Hymenochaetaceae ) / Dissecado em 15.xii.2022 / HOLOTYPUS ♂ ”; CELC. ( Fig. 89D–E View Fig )

Paratypes

BRAZIL • 1 ♂, 1 ♀ (1 ♂ *, 1 ♀ *); same collection data as for holotype; 3 Dec. 2022; E. von Groll leg.; “/ Em Inonotus sp. ( Hymenochaetaceae )”; CELC .

Description

COLOURATION. Brown; antennae, clypeus, mouthparts, tarsi, apex of abdominal ventrites, and tip of elytra light ochreous; femora and tibiae ochreous ( Fig. 89A View Fig ).

HEAD. Punctations moderately dense and coarse, some punctures coarser. Antennomeres elongate ( Fig. 89J–K View Fig ); proportions (n =3): I 89/42:II 83/40: III 60/17: IV 76/16: V 89/16:VI 85/16: VII 99/28: VIII 71/19: IX 95/30:X 94/33: XI 126/36.

PROTHORAX ( Figs 89L View Fig , 90A–C View Fig ). Pronotum elongate, slightly tapering towards to head, not strongly curved in lateral view ( Fig. 89B View Fig ); punctures moderately coarse; pubescence moderately sparse. Posterior angle of pronotum somewhat acute, and almost at same position as anapleural line ( Fig. 90A–C View Fig ).

MESOTHORAX ( Fig. 90A–C View Fig ). Tip of scutellum just partially exposed (longer than wide), hardly visible. Mesanepisternum finely punctate; pubescence sparse. Secondary lines connected to mesocoxal cavities.

METATHORAX ( Fig. 90A–C View Fig ). Metaventrite lacking microsculpture, almost glabrous; with coarse punctures next to submesocoxal lines – density variable. Submesocoxal lines slightly truncate laterally; connected at midline, forming an acute angle ( Fig. 90E View Fig ); submesocoxal area: 0.07–0.08 mm. Metanepisternal suture almost straight or sinuous, impunctate; metanepisternum mostly covered by elytra.

WINGS ( Figs 89A–C, F–H View Fig , 90D View Fig ). Elytra with moderately sparse punctures, some coarser than other, both coarser than on pronotum. Sutural striae not strongly shortened, extending from apex to approximately 0.84 of the elytral sutural length; variation: female with shorter striae: 0.47 of the sutural length. Lateral striae impunctate, slightly opening at humeral region ( Fig. 89B View Fig ).

LEGS ( Figs 90E–F View Fig , 92A–B View Fig ). With imbricate microsculpture.

ABDOMEN. Sparsely pubescent. Anterior two-thirds of ventrite I ( Figs 89B View Fig , 90A–C View Fig , 92C–D View Fig ), and tergites ( Fig. 90G View Fig ) with imbricate microsculpture; remaining ventrites without microsculpture.

Males

Sternite VIII shortened, with acute posterior projection ( Fig. 90H View Fig ). Tergite VIII without posterior projection ( Fig. 90I View Fig ). Tergite IX with ventral struts short and almost straight ( Fig. 90J View Fig ). Sternite IX acute posteriorly ( Fig. 90K View Fig ). Tergite X triangular ( Fig. 90L View Fig ).

AEDEAGUS ( Fig. 91 View Fig ). Basal bulb 2× as long as apical lobe; apical lobe bent ( Fig. 91B View Fig ). Parameres thin, bearing a poorly sclerotized lobe ( Fig. 91B View Fig ); sclerite of internal sac curved, D-shaped ( Fig. 91D View Fig ).

MEASUREMENTS (n=2, including holotype; in mm; * = invariant). TL 1.56–1.60 (1.58± 0.03), SY 0.19 *, HW 0.42–0.43 (0.43± 0.01), IS 0.14–0.15 (0.14 ± 0.01), WA 0.26–0.27 (0.27 ± 0.01), PL 0.64–0.65 (0.64 ± 0.01), PA 0.40–0.41 (0.41± 0.01), PB 0.76–0.79 (0.78 ± 0.02), EI 1.03–1.06 (1.05± 0.02), EL 1.11–1.14 (1.13± 0.02), EW 0.41 *, EH 0.40–0.41 (0.41 ±0.01), MB 0.10 *, MC 0.29–0.33 (0.31± 0.03), MeW 0.25 *, ML 0.08 *, VL 0.20–0.21 (0.21± 0.01), VL2 0.32 *, PrF 0.40–0.41 (0.41± 0.01), PrT 0.31– 0.33 (0.32± 0.01), MsF 0.46 *, MsT 0.36–0.37 (0.37 ± 0.01), MtF 0.47–0.50 (0.49 ±0.02), MtT 0.45–0.49 (0.47 ±0.03).

Female ( Fig. 92 View Fig )

Sternite and tergite VIII with imbricate microsculpture. Sternite VIII with an acute posterior projection ( Fig. 92E View Fig ). Tergite VIII lacking projections ( Fig. 92F View Fig ). Distal gonocoxite slightly fusiform, gonostylus elongate ( Fig. 92G–H View Fig ).

MEASUREMENTS (n =1; in mm). TL 1.70, SY 0.22, HW 0.46, IS 0.17, WA 0.30, PL 0.69, PA 0.44, PB 0.78, EI 1.13, EL 1.20, EW 0.43, EH 0.43, MB 0.12, MC 0.34, MeW 0.26, ML 0.07, VL 0.20, VL2 0.36, PrF 0.43, PrT 0.31, MsF 0.49; MsT 0.38, MtF 0.50, MtT 0.45.

Host

Collected from Inonotus sp. , located on a tree in front of an avenue ( Figs 1E–F View Fig , 94A–B View Fig ).

Remarks

Similar to T. distortum sp. nov., differing mainly by the more elongate body, the longer submesocoxal area – reaching half of the metaventrite, by the presence of microsculpture on the ventrite I, the less sclerotized tergite IX, the shorter apex of the median lobe, the thinner parameres, and by the shape of the sclerite (D-shaped). Although the female has a larger size and a shorter sutural stria compared to the males, the specimen exhibits all other characteristics of the species. Therefore, these differences can be considered merely intraspecific variation.

Distribution

Universidade Federal de Viçosa, campus of Viçosa, state of Minas Gerais, Southeast Brazil ( Fig. 1A–B, E–F View Fig ).