Tetradonia ramirezi Gualdron-Diaz & Chani-Posse 2024, sp. n.
Creators: name: Gualdrón-Díaz, Juliette C.
name: Chani-Posse, Mariana R.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Tetradonia
Tetradonia ramirezi

description: Tetradonia ramirezi Gualdrón-Diaz & Chani-Posse sp. n.
Figs. 18–33
Material studied. Holotype ♂, COLOMBIA, with one label: “ COLOMBIA, Santander / Tona, Golondrinas, / 7.169912, -73.03480 1400m Mayo-2018 / foraging ants in a / column of Eciton burchellii / Daniel F. Silva, leg.” [white, printed] (MPUJ_ENT). Paratypes, 2 ♂ (dissected on slides): same data as for holotype.
Diagnosis. T. ramirezi Gualdrón-Diaz & Chani-Posse sp. n. differs from the other species of Tetradonia by the following combination of characters: elytral surface weakly punctate with one macroseta near scutellum and three on the lateral margin (the first macroseta is larger than the other two); pronotum with four small macrosetae along midline and four long macrosetae along lateral margin; antennomere 4 short; tergite VII with 3+3 macrosetae without a raised area; tergite VIII with the inner points bluntly rounded and the outer two narrowly rounded.
Description.
Measurements: LPL: 1.24; LEL: 1.91; HW: 0.65; HL: 0.52; AL: 1.8; PW: 0.70; PL: 0.62; EL: 0.26; TL:0.06; NW: 0.25; EtW: 0.54; EtL: 0.69.
Body length 3.35 mm (Figs. 18–19); head and pronotum dark brown; elytra, abdomen, antennae, and legs light brownish; abdomen with long erect dark brown setae; pronotum, elytra and sternites abdominal with short recumbent light brown setae; whole body shining.
Head capsule transverse (HW/HL = 1.25), slightly narrower than pronotum at widest point (HW/PW = 0.92); surface smooth and shiny, covered with short, thin, and recumbent light brown setae; eyes large, distinctly convex, notably longer than temples (EL/TL=4.3) seen from above; antennae long (Fig. 20), slightly shorter than head, pronotum and elytra combined (AL = 1.8 mm); all antennomeres longer than wide; antennomeres 2–10 slightly wider toward apex; scape long, widened medially, slightly shorter than antennomeres 2 and 3 combined; pedicel abruptly wider from medial portion toward apex, apical area translucent; antennomere 4 short, 2.9 x shorter than scape; last antennomere parallel sides, narrowed apically into a rounded apex.
Labrum transverse, 1.65 x as wide as long, with 16 setae on each side of midline, most of them on anterior half, lateral margins convex, anterior margin concave, posterior margin nearly straight with two long apodeme (Fig. 21); labium with ligula bifid and short, divided to near midpoint into 2 widely separated rounded lobes; prementum with discal seta widely separated, medial pseudopore field with a few pseudopores near base, lateral pseudopore fields with two real pores and one setal pore; labial palpi 3-articled, first and second article subequal in length, article 3 a bit longer, the first two articles bear several setae and some pores; mentum trapezoidal, anterior margin concave, lateral and posterior margins almost right with corners rounded, two transverse rows of four setae each, the pair of setae near to the corner of anterior margin very long, several sensory pores primarily on each side of midline (Fig. 22); mandibles nearly symmetrical, right mandible bears large tooth, left mandible lacking teeth (Fig. 23); maxillae with galea elongate and densely setose at apex, lacinia elongate, longer and wider than galea, with some short setae near base, numerous long setae on middle third and densenly setose toward at apex; maxillary palpi with palpomere I tranverse and very short, palpomere II a bit longer than III, with few long setae, palpomere III a bit wider than II, with several long setae, apical palpomere much narrower, lacking setae (Fig. 24)
Pronotum transverse, 1.13 x as wide as long, distinctly margined; dorsal surface smoothly convex covered with short recumbent light brown setae; four small macrosetae along midline and four long macrosetae along lateral margin; anterior margin convex; lateral margins broadly convex to nearly straight, converging slightly towards the base; hypomera visible in lateral view; elytra slightly longer than pronotum; punctate, shining, covered with short recumbent light brown setae, with one macroseta near scutellum and three on the lateral margin (the first macroseta is larger than the other two); lateral margins broadly convex and with anteromesial border densely scaled (Fig. 27); hind wings fully developed, wing flabellum with nine rays attached to a short broad lobe (Fig. 26). Mesoventrite with intercoxal process extremely short and broad; metaventral process longer than mesoventral process, with apex truncated (Fig. 25).
Abdomen with tergite III with two macrosetae; tergites IV–V with four macrosetae; tergite VI with six macrosetae; sternite IV with a pair of gland reservoir on the anterior margin; tergite VII (Fig. 28) with 3+3 long macrosetae and 8+8 short fine macrosetae along the apical margin; margin posterior with a dense apical comb consisting of two types of teeth (Fig. 28a); paratergites with 1+1 macrosetae; sternite VII (Fig. 29) with three rows of dark brown strong macrosetae and two rows of yellow fine macrosetae; tergite VIII (Fig. 30) with four distinct processes on the posterior margin, two on each side of the longitudinal midline, 4+4 long macrosetae and several short fine setae on lateral margin; sternite VIII (Fig. 29) narrower apically; anterior margin concave, with 7+7 black long macrosetae, several pale short macrosetae, and fine setae along the posterior margin; tergite and sternite IX as in Fig. 32, with 4+4 macrosetae on the lateral lobes and 4+4 macrosetae on the median lobe, and with a row of yellow fine setae at the base of the median lobe.
Male.Aedeagus elongated and sclerotized; median lobe with base bulbous and apical portion gradually narrowed toward apex, with athetine bridge present (Fig. 33); parameres, as in Fig. 33.
Female. Unknown
Remarks. T. ramirezi reminds of T. marginalis Reichensperger, 1935. These species share the presence of large eyes, not occupying the entire sides of head; pronotum with four long macrosetae along lateral margin; elytra with three macrosetae on lateral margin and sternite VIII with 7 + 7 macrosetae. However, T. marginalis can be distinguished from T. ramirezi not only by a different color pattern but also by the elytral surface, which is smooth and not punctate in T. marginalis, as opposed to that of T. ramirezi, which is punctate. Additionally, T. marginalis bears four macrosetae on tergite III, whereas T. ramirezi has only two. Finally, the antennomere 4 in T. marginalis is quadrate, while in T. ramirezi, it is slightly longer than wide.
Geographical distribution. The new species is only known from its type locality, Golondrinas in Tona, Santander, Colombia.
Etymology. The specific name is dedicated to Dr. José Ramírez-Salamanca, a staphylinologist, colleague, and dear friend.
Natural history and habits. Specimens were collected by Daniel F. Silva from a column of Eciton burchellii while they were foraging for ants. It was observed that these species were located at the edges of the raid, where they captured the smaller workers and even attempted to steal the food carried by the ants (pers. comm.).
description: Published as part of Gualdrón-Díaz, Juliette C. & Chani-Posse, Mariana R., 2024, First record of the genus Tetradonia Wasmann, 1894 (Coleoptera: Staphylinidae: Aleocharinae) in Colombia, with description of two new species, pp. 181-191 in Zootaxa 5474 (2) on pages 187-190, DOI: 10.11646/zootaxa.5474.2.6, http://zenodo.org/record/12567475