Omalodes (Omalodes) atacamanus Leivas & Degallier, sp. nov.
Creators: name: Leivas, Fernando W. T.
name: Degallier, Nicolas
name: Almeida, Lúcia M.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Histeridae
Omalodes
Omalodes atacamanus

description: Omalodes (Omalodes) atacamanus Leivas & Degallier sp. nov.
Type locality. Chile, Província de Antofagasta, Taltal (Paposo).
Type material. Holotype: (♂) [“ CHILE II REGION/Tal-Tal Paposo/ 24 Octubre 1997 /Leg. V.M. Diéguez M.” “ COLLECION /V.M. Diéguez M.” “ Omalodes /(Diplogrammicus)/ intermedius (Lewis, 1907) / Det. G. Arriagada 2001”] (MNHNC). Paratypes (15) (1 ♂) [“ CHILE III Región/Bahia Esmeralda/ 23.X.1999 /leg. Guildo Castillo” “ Omalodes /(Diplogrammicus)/ intermedius (Lewis) / Det. G. Arriagada 2008”] (DZUP); same data and labels (1 ♀ MNHNC); (1 ♀ CHND); (1 ♀ VMDC); (1 ♂) [“ CHILE II REGION/Taltal/ 22.10.85 /leg. G. Arriagada” “ COLLECION /V.M. Diéguez M.” “ Omalodes / intermedius /G. ARRIAGADA DET. 1997”] (MNHNC); (1 ♀) [“ CHILE II REGION/Taltal/ 22.10.85 /leg. G. Arriagada” “ COLLECION /V.M. Diéguez M.” “ Omalodes / (Diplogrammicus)/ intermedius (Lewis, 1907) / Det. G. Arriagada 2001”] (MNHNC); (2 ♂) [“ CHILE II REGION/ Paposo/ 05.10.92 /leg. G. Castillo” “ COLLECION /V.M. Diéguez M.” “ Omalodes /(Diplogrammicus)/ intermedius (Lewis, 1907) / Det. G. Arriagada 2001”] (DZUP); (2 ♀) [“ CHILE II REGION/Tal-Tal Paposo/ 24.Octubre 1997 / Leg. V.M. Diéguez M.” “ COLLECION /V.M. Diéguez M.” “ Omalodes /(Diplogrammicus)/ intermedius (Lewis, 1907) / Det. G. Arriagada 2001”] (DZUP); (1 ♀) [“ CHILE II REGION/Tal-Tal Paposo/ 24.Octubre 1997 /Leg. V.M. Diéguez M.” “ COLLECION /V.M. Diéguez M.” “ Omalodes /(Diplogrammicus)/ intermedius (Lewis, 1907) / Det. G. Arriagada 2001”] (VMDC); (1 ♀) [“Taltal/S. la Quinta/ 5.10.1985 /Coll. M. Elgueta” “Bajo cactus/ Copiapoa cinerea ” “ COLLECIÓN MNHN / Chile - SANTIAGO” “ Omalodes /(Diplogrammicus)/ intermedius /(Lewis, 1907)/ Det. G. Arriagada 2001”] (MNHNC); (1 ♀) [“ Chile Atacama/Paposo/La Rinconada/ 10.10.1983 /leg. M. Elgueta” “ COLLECIÓN MNHN / Chile - SANTIAGO” “ Omalodes /(Diplogrammicus)/ intermedius /(Lewis, 1907)/ Det. G. Arriagada 2001”] (CEMT); (2 ♂) [“ Chile Anfogasta/Tatal/ 19.09.1957 /leg. G. Kuschel” “ COLLECIÓN MNHN / Chile - SANTIAGO” “ Omalodes /(Diplogrammicus)/ intermedius /(Lewis, 1907)/ Det. G. Arriagada 2001”] (MNHNC).
Diagnosis. Frons flat (Fig. 2 D); marginal stria of prosternal lobe absent (Fig. 2 E, F); posterior margin of the elytra with longitudinal strioles (Fig. 3 E); lateral metaventral stria oblique; all tibiae with a row of setae on outer submarginal region (Fig. 3 B–D); profemora with sparse setae on the posterior surface (Fig. 2 E–F); propygidium and pygidium with punctuation similar to the dorsum (Fig. 3 E); 9th tergite without lateral projections (Fig. 4 M).
Description. Length (pronotum+elytra) 5.3–6.6 mm, elytral width (humeral region): 3.7–4.7 mm. Color dark or dark-brown. Body shape subrectangular, glabrous, covered by ground punctuation (Figs. 2 A–B). Frons and clypeus flat; frontal stria inwardly curved and usually complete; supraorbital stria usually absent or rudimentary; frontoclypeal suture weakly marked only laterally (Fig. 2 D); postoccipital stria complete not setose; fovea of postgena present. Antennal scape basally slender (Fig. 2 D) and with subrectangular elevation at the apical region (Fig. 2 D, see also Fig. 6 F); fifth and sixth segments of the funicle not expanded laterally; antennal club with pseudo-sutures slightly inwardly arcuate and with a distinct apical sensorial area. Palpifer maxillary with robust setae on the external margin and without setae on the internal margin; lacinial hook absent. Submentum subpentagonal and with long setae on the surface; anterior margin of the mentum medially emarginate. Prothorax FIGURE 4. Omalodes (Omalodes) atacamanus sp.nov., female terminalia (A–F) and male terminalia (G-N). A. Bursa copulatrix, common oviduct, spermatheca and spermathecal gland; B. Basal region of bursa copulatrix, spermatheca and spermathecal gland; C, Coxites in ventral view; D. Close of apex of the coxites in ventral view; E, Coxites in dorsal view; F, Coxites in lateral view; G. Aedeagus in dorsal view; H. Aedeagus in lateral view; I. Aedeagus in ventral view; J. 8th tergite; K. 8th sternite; L, Close of the apex of 8th sternite, setae on the apex; M. 9th and 10th tergites; N. 9th sternite. Scale: A, C, E–K, M, N (0.5 mm) and B, D, L (0.25 mm).
with deep cavity to insert the antennal club; prosternal lobe not longer than 1/3 of the total length of the prosternum, anterior margin rounded or feebly truncated, marginal prosternal stria absent, lateral extension of the prosternal lobe without projections; lateral marginal prosternal stria weak and marked only next to procoxae; prosternal keel with transverse elevation medially (Figs. 2 E–F), anterior half with two parallel carinal prosternal striae, posterior margin acuminate (Fig. 2 E), posterior gland openings located below the lateral marginal striae (Fig. 2 E). Pronotum with lateral posterior extremity not rounded, posterior margin with obtuse angle (Fig. 3 A); marginal pronotal stria usually complete; lateral pronotal stria complete. Elytra with posterior and sutural regions not depressed; posteriorly emarginate (Figs. 2 A, C) and with longitudinal strioles; 1st dorsal elytral stria complete, 2nd dorsal elytral stria variable on its length, 3rd dorsal stria short, not exceeding the anterior half of elytra, 4th and 5th dorsal striae variable on its length, sutural elytral stria absent (Fig. 2 A), inner subhumeral stria absent, outer subhumeral stria variable on its length, epipleural region with one stria not reaching the posterior margin. Mesoventrite, anterior margin strongly emarginate medially, laterally with shallow excavations for receiving the anterior trochanters; marginal mesoventral stria interrupted medially; discal mesoventral stria absent (Fig. 2 F). Metaventrite with lateral stria oblique, postmesocoxal stria absent (Fig. 2 B). Profemora with setae on the posterior surface (Figs. 2 E–F); all tibiae with a row of setae on outer margin and submarginal region (Figs. 3 B–D). Protibiae truncated with a weak emargination at apex; inner row of setae ending in an apical cluster (Fig. 3 B); tarsal cavity slightly sinuous; internal region of tarsal cavity with a differentiated sulcus with setae. Stria of 1st visible abdominal sternite marked only laterally and sometimes rudimentary. Propygidium and pygidium with punctuation similar to the dorsum, the first one with punctuation slightly thicker on the sides (Fig. 3 E). Pygidium longer than half propygidium length and with regular punctuation (Fig. 3 E).
Male terminalia. 10th tergite cordiform and composed of two regions more sclerotized but sometimes with separation not clear; 9th tergite without lateral projections (Fig. 4 M); 9th sternite “U”-shaped (Fig. 4 N); 8th sternite composed of two sclerites, with setae on the lateral-posterior region (Figs. 4 K–L); 8th tergite with basal membrane attachment line, basal margin emarginate (Fig. 4 J). Aedeagus, basal piece about 1/3 parameres length, with a dorso-lateral projection, anterior margin in dorsal view strongly emarginate on the middle (Figs. 4 G, H). Parameres with posterior margin medially emarginate; in lateral view subcylindrical on anterior region (Fig. 3 H), posterior region slightly narrowed; ventrally fused on anterior region by a weakly sclerotized region, posterior region with setae, with the extremity rounded and oblique sides.
Female terminalia. Spermatheca with constraining rings, longer than wide and inserted on the anterior extremity of bursa copulatrix (Figs. 4 A–B). Spermathecal gland connected at the base of spermatheca and bigger than it, duct of spermathecal gland with constraining rings (Figs. 4 A–B). Common oviduct inserted on the posterior region of the bursa (Fig. 4 A). Coxites without a subapical lateral projection next to the cavity for insertion of stylus; in lateral view with internal and external margins carinate (Figs. 4 C–E).
Remarks. The frontal stria can be anteriorly discontinuous; supraorbital usually developed, but incomplete; frontoclypeal suture very discrete (imperceptible in some specimens). In the male, the suture between the prosternal keel and the lobe can have two glands opening at the middle (Figs. 2 E–F), but it is not consistent in the species; the carinal stria of the prosternal keel may vary in length. Pronotal marginal stria may be slightly interrupted in the middle of the anterior margin of pronotum. Between the first and third dorsal striae there may be several short and random striae; second elytral dorsal stria can be complete or absent on the posterior half or posterior third; fourth and fifth dorsal striae can be short or absent; outer subhumeral stria is usually discontinuous next to apical extremity of humeral stria. The sulcus on internal region of tarsal cavity can be formed by strong and close punctures.
Geographic distribution. The new species is known only from the Antofagasta Province (Taltal, Paposo and Bahia Esmeralda) along the arid coastal region of Chile, in the Atacama biogeographic province (described by O’Brien 1971) which belongs to the South American Transition Zone (Morrone 2006; 2014). This zone is characterized by the overlapping areas of Neotropical and Andean biotic components. The Atacama biogeographic province has an entomological fauna related with that from Coquimbo (belonging to Central Chilean Subregion of Andean Region) (Morrone 2006). Several taxa of Magnoliophyta (plants), Arthropoda (including Coleoptera) and Vertebrata are reported as endemic to the Atacama province (Morrone 2014).
Biology. The adults and larvae of Omalodes atacamanus sp. nov. were found within Copiapoa cinerea (Philippi) Britton & Rose (Plantae: Cactaceae) feeding on the larvae of Drosophilidae and Syrphidae (Volucella sp.) (Arriagada 1985; 1986, cited it as Omalodes (Diplogrammicus) intermedius Lewis). All specimens were collected in September and October in the BWk region (cold desert) where the mean annual temperature is <18°C (Peel 2007). Living in cold desert environments in South America appears to be a unique feature of Omalodes atacamanus sp. nov. among the Omalodini, since other species of Omalodes and Ebonius occupy tropical and subtropical areas, with only a few species of Omalodes found in xeric areas in New Mexico and Arizona (USA) (Kovarik & Caterino 2001). The presence of setae on the outer submarginal region of anterior, middle and hind tibiae, as well as on the surface of the femur represent possible adaptations to sandy environments in order to increase the surface of contact of the beetle's body with the sand, and thus assist in the vertical movement in sandy soil.
Etymology. The species’ name refers to the desert region of Atacama, where this species has been found.
description: Published as part of Leivas, Fernando W. T., Degallier, Nicolas & Almeida, Lúcia M., 2015, New species of Omalodes and redefinition of the tribe Omalodini (Coleoptera: Histeridae: Histerinae), pp. 109-119 in Zootaxa 3925 (1) on pages 111-116, DOI: 10.11646/zootaxa.3925.1.7, http://zenodo.org/record/236793