Geiserocerus flavifrons Roza, 2025, sp. nov.
Creators: name: Silva Roza, André
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Phengodidae
Geiserocerus
Geiserocerus flavifrons

description: Geiserocerus flavifrons sp. nov.
Figs 1, 2, 3, 4, 5, 6
Etymology.
A combination of the Latin adjective flavus, “ yellow ”, and feminine noun frons, “ forehead ”, in reference to the yellowish coloration present on the anterior region of the head of the specimens of this species. Name in apposition.
Type locality.
Los Volcanes refugee, Amboro National Park, Santa Cruz, Bolívia.
Diagnosis.
Body overall brown to dark brown, with light brown antennae and yellow to yellowish brown head dorsally and ventrally (anterior region to almost the entire head, varying between specimens), prosternum, mesosternum, legs and aedeagus (Fig. 1 A, B). Eyes occupying almost 1 / 6 of head width in dorsal view (Figs 1 C, 2 A); in lateral view, posterior margin vertical, straight (Figs 1 D, 2 C). Antennomere IV 1.5 × as long as III, crescent until VIII, IX subequal to VIII and X – XI slightly decrescent, XII subequal to XI (Fig. 2 I). Pronotum slightly wider than long, anterior margin rounded, posterior margin slightly curved (Figs 1 C, 3 A). Elytron around 3 × as long as wide (Fig. 4 A).
Description.
Male. Measurements (n = 6): Total length: 4.55–5.50 mm (aver. 4.90 mm, 5.50 mm in holotype). Head length: 0.59–0.66 mm (aver. 0.61 mm, 0.57 mm in holotype). Head width: 0.84–0.90 mm (aver. 0.88 mm, 0.89 mm in holotype). Pronotum length: 0.69–0.76 mm (aver. 0.73 mm, 0.74 in holotype). Pronotum maximum width: 0.74–0.83 (aver. 0.81 mm, 0.82 in holotype). Elytron length: 1.56–1.62 mm (aver. 1.58 mm, 1.56 mm in holotype). Elytron maximum width: 0.48–0.51 mm (aver. 0.50 mm, 0.48 in holotype).
Morphology: Head slightly wider than long, integument glossy, smooth, coarsely punctate, eyes small, feebly protruding, occupying around 1 / 6 of the width in dorsal view (Figs 1 C, 2 A) post-ocular area subequal to eye length in lateral view, posterior margin straight, straight (Figs 1 D, 2 C); antennomere IV 1.5 × as long as III, crescent until VIII, IX subequal to VIII and X – XI slightly decrescent, XII subequal to XI (Fig. 2 J); maxilla with last palpomere as long as the three preceding ones combined (Fig. 2 F); labium with last palpomere 1.5 × as long as the two preceding ones (Fig. 2 G). Pronotum slightly wider than long, integument glossy, smooth, coarsely punctured, anterior margin rounded, lateral margins dorsally subparallels, slightly convergent anteriorly, posterior margin slightly curved (Figs 1 C, 3 A). Elytron heavily setigerous punctate, around 3 × as long as wide (Fig. 4 A). Posterior wings with venation as in the genus description (Fig. 4 C). Tergite IX transversal, 2 × as wide as long in the middle line; tergite X 2 × as long as wide (Fig. 5 E); Sternite VIII with posterior margin slightly marginated (Fig. 5 D); sternite IX almost 2 × as long as wide when including membranous area, posterior margin distinctly emarginate (Fig. 5 F). Aedeagus with phallobase sclerotized, transverse and shaped as a ribbon-like stripe, medially separated; median lobe cylindrical, strongly curved at base, rounded and not constricted apically, flagellum encircled around median lobe at rest; about 2 × as long as median lobe length, with serration in the apical half; paramere parallels, slightly asymmetrical, narrowing slightly past the middle towards the apex, which is truncate, toothed innard, with short and scarce bristles (Fig. 5 G – I).
Coloration. Body overall brown to dark brown, with light brown antennae, brown to yellowish brown head dorsally and ventrally (anterior region to almost the entire head, varying between specimens – yellowish brown in the anterior half, medially yellowish brown and laterally brown in the posterior half of the holotype), yellowish light brown prosternum, mesosternum, legs and aedeagus (Fig. 1 A, B).
Immatures and females. Unknown.
Biology and distribution.
Geiserocerus flavifrons sp. nov. is only known to occur in the Parque Nacional Amboró, Santa Cruz, Bolívia (Fig. 6). The National park is a region where four major biomes come into contact: the humid vegetation from Amazonia, the seasonal subtropical lowland vegetation from the Chaco, the subtropical highland vegetation from the Andes and the seasonal vegetation of the Chiquitanía (Ibisch et al. 2003). The specific site of the sampling, Los Volcones refugee, has a heterogeneous phytophysiognomy, being composed of elements belonging to seasonal forests as well as to humid tropical forests (Linares-Palomino et al. 2008).
All specimens were collected between November and December, by the end of the spring and beginning of the summer in the southern hemisphere. Species of this genus were never seen alive, so there is no data regarding their habits.
Type material.
Holotype: BOLIVIA. Santa Cruz. BOLIVIA: Santa Cruz / Amboro National Park / Los Volcanes, c. 1000 m / S18°06’ W63°36’ / 20 / xi- 12 / xii / 2004 \\ Flight Intercept Trap / Mendel, H. & / Barclay, M. V. L. / BMNH (E) 2004-280 \\ Geiserocerus / flavifrons / HOLOTYPE / det. Roza, A. S. (1 male) (BMNH). Paratypes: Santa Cruz. BOLIVIA: Same data as holotype except last label: Geiserocerus / flavifrons / PARATYPE / det. Roza, A. S. (2 males) (BMNH), (1 male) (DZRJ); Santa Cruz / Amboro National Park / Los Volcanes, c. 1000 m / S18°06’ W63°36’ / 20 / xi- 12 / xii / 2004 \\ Flight Intercept Trap / Mendel, H. & / Barclay, M. V. L. / iBMNH (E) 2004-280 \\ Eurymastinocerus sp. / Quintino, H. Y. S. det 2017 \\ Geiserocerus / flavifrons / PARATYPE / det. Roza, A. S. and a (1 male) (BMNH); Santa Cruz / Amboro National Park / Los Volcanes, c. 1000 m / S18°06’ W63°36’ / 20 / xi- 12 / xii / 2004 \\ Flight Intercept Trap / Mendel, H. & / Barclay, M. V. L. / BMNH (E) 2004-280 \\ Phengodidae / det E. Jiménez-Sánchez 2006 \\ Geiserocerus / flavifrons / PARATYPE / det. Roza, A. S. and a (1 male) (BMNH).
description: Published as part of Silva Roza, André, 2025, A new genus and a new species of railroad-worm beetles from Bolivia (Coleoptera, Phengodidae, Mastinocerinae), pp. 203-212 in Contributions to Entomology 75 (1) on pages 203-212, DOI: 10.3897/contrib.entomol.75.e143153