Tomosomus subtestaceus Motschulsky, 1855

Telnov, Dmitry & Gusakov, Alexey A., 2023, Rediscovery of Tomosomus Motschulsky, 1855 (Coleoptera: Anthicidae) with redescription of the genus, a new genus-rank synonym, and a key to species, Zootaxa 5293 (3), pp. 541-556 : 554-555

Tomosomus subtestaceus Motschulsky, 1855 ( Figs 1–4 )

Tomosomus subtestaceus — Motschulsky (1855: 18) original description.

Type material examined. Lectotype ♁ [designated herewith] MZUM ( Figs 1–2 ): ly [handwritten, label green, circular] // Type [handwritten] // Tomosomus subtestaceus Motsch Panama Obispo [handwritten, label green].

Paralectotypes 2♁ & 2♀ MZUM ( Fig. 1 ): same labels as lectotype [not sexed] .

[All type specimens are in reasonably good condition].

New material. 75 specimens MIUP , 10 specimens BMNH & 30 specimens DTC ( Fig. 3 ): IBISCA Project Panama Colon San Lorenzo NP [printed] // IBISCA 20030-05 Morphospec. Sort Juergen Schmidl COANTH 8 [printed] .

The lectotype designation is made in order to maintain nomenclatural stability since T. subtestaceus is the type of its genus.

Redescription. Lectotype ♁, total body length 2.2 mm; head 0.42 mm long, across compound eyes 0.33 mm broad, pronotum 0.56 mm long, maximum width 0.5 mm, minimum width 0.27 mm, elytra 1.35 mm long, 0.85 mm combined wide. Paralectotype 1 ♁, total body length 1.95 mm; head 0.38 mm long, across compound eyes 0.27 mm broad, pronotum 0.47 mm long, maximum width 0.45 mm, minimum width 0.25 mm, elytra 1.22 mm long, 0.75 mm combined wide. Paralectotype 2 ♁, total body length 2.0 mm; head 0.39 mm long, across compound eyes 0.28 mm broad, pronotum 0.49 mm long, maximum width 0.45 mm, minimum width 0.27 mm, elytra 1.25 mm long, 0.77 mm combined wide. Paralectotype 3 ♀, total body length 2.1 mm; head 0.42 mm long, across compound eyes 0.32 mm broad, pronotum 0.52 mm long, maximum width 0.49 mm, minimum width 0.27 mm, elytra 1.27 mm long, 0.83 mm combined wide. Paralectotype 4 ♀, total body length 2.25 mm; head 0.42 mm long, across compound eyes 0.33 mm broad, pronotum 0.56 mm long, maximum width 0.52 mm, minimum width 0.28 mm, elytra 1.3 mm long, 0.85 mm combined wide.

Dorsum and venter brown, forebody somewhat paler brown. Mouthparts, antennae, palps and legs pale yellow, abdomen yellowish brown. Head subtriangular, glossy dorsally and ventrally, slightly convex in dorsal aspect. Anterolateral margin of frons slightly bulging between antennal insertion and internal anterior margin of a compound eye. Compound eye moderate, protruding beyond lateral outline of head. Tempus rounded and constricted towards subtruncate head base. Head dorsal punctures minute and inconspicuous. Head dorsal setae moderately long, sporadic. Antenna extending slightly beyond humeral area of elytron when directed posteriad. Antennomere three about same length as antennomere two, antennomeres 8–10 distinctly thickened, transverse. Terminal antennomere elongate triangular with tapered apex, asymmetrical, 2.25× as long as penultimate antennomere. Penultimate maxillary palpomere subtriangular. Terminal maxillary palpomere securiform. Pronotum dorsally and laterally glossy, slightly convex in dorsal aspect, anterior lobe wider than head across compound eyes. Front margin of anterior lobe subtruncate, dorsally and laterally with very narrow anterior rim. Anterior lobe with shallow, moderately broad, median longitudinal sulcus (this sulcus is moderately present, nearly obsolete in some specimens). Posterior lobe strongly narrower and shorter than anterior. Postmedian lateral constriction deep and broad, dorsally with a row of moderate punctures with raised, narrow, longitudinally directed intervening spaces, continues onto pronotal disc as a shallow depression (in lateral view). Pronotal punctures minute, sparse, intervening spaces significantly wider than punctures. Dorsal pronotal setae whitish, sparse, subdecumbent. Pronotal tactile setae yellowish, long, erect, sporadic, mainly aligned along with lateral margins of pronotum. Scutellar shield minute, subtriangular, rounded at posterior margin. Elytra ovoid, moderately convex in dorsal aspect, widened laterally before midlength, humerus obsolete (apterous species). Elytral punctures much stronger and larger than those on the dorsal forebody including in the lateral constriction area, becoming smaller on the posterior half of elytron. Intervening spaces glossy and glabrous, in the basal third of elytron as wide as to twice as wide as punctures. Posterior sutural angle prolonged into a short, acute denticle ( Figs 2C , 3A ). Epipleuron nearly complete, moderately broad. Elytral setae whitish to yellowish, long, rather sparse, suberect to erect. All femora clavate. Protibia at posterior margin with distinct, obtusely angulate postmedian swelling ( Fig. 3D ). Basal metatarsomere longer than combined length of remaining metatarsomeres. Tergite VII broadly rounded at posterior margin, with broad median longitudinal furrow ( Fig. 4A ). Morphological sternite VII broadly rounded at posterior margin ( Fig. 4B ). Morphological sternite VIII broadly emarginate at posterior margin ( Fig. 4C ). Morphological sternite IX as in Fig. 4D . Aedeagus elongate, tubular, apically rounded, slightly curved in lateral view ( Figs 2C , 4E–G ).

Sexual dimorphism. Female protibia not or only slightly swollen at posterior margin. Morphological sternite VIII without apical emargination. Morphological sternite IX rod-like, without accessory arms.

Ecology. Species of lowland rainforests.

Distribution. Panama. Type locality ‘Obispo’, as of Selander & Vaurie (1962) and Chandler (2013), was a settlement ‘on the Río Obispo across the Chagres River from the site of Gamboa which is today along the transisthmus railroad’. Today the area is known as Bas Obispo (9°06’00’’N 79°40’59’’W).

Type depository. MZUM.

Figures

FIGURE 1. Tomosomus subtestaceus Motschulsky, 1855. A—Paralectotypes ♀♀, habitus, laterodorsal view; B—Lectotype ♁ (upper specimen) and paralectotypes ♁♁, habitus, dorsal view; C—Labels [not to scale].

FIGURE 2. Tomosomus subtestaceus Motschulsky, 1855. A—Lectotype ♁, habitus, dorsal view; B—ditto, lateral view; C— Apex of elytra, tergite VII and aedeagus, dorsal view [not to scale]. Images courtesy Kirill V. Makarov (Moscow, Russia).

FIGURE 3. Tomosomus subtestaceus Motschulsky, 1855, ♁ from San Lorenzo NP, Panama.A—Habitus, dorsal view; B—ditto, lateral view; C—ditto, pro-, meso- and metathorax, ventral view; D—Foreleg including procoxa [not to scale].

FIGURE 4. Tomosomus subtestaceus Motschulsky, 1855, ♁ from San Lorenzo NP, Panama, terminalia and genitalia. A— Tergite VII, dorsal view; B—Morphological sternite VII, ventral view; C—Morphological sternite VIII, ventral view; D— Morphological sternite IX; E—Aedeagus, ventral view; F—ditto, lateral view; G—ditto, apex, ventral view [not to scale].