Lasiodactylus kelleri Cline

Cline, Andrew R. & Carlton, Christopher E., 2004, Review of Lasiodactylus Perty, with Descriptions of Three New Species (Coleoptera: Nitidulidae: Nitidulinae), The Coleopterists Bulletin 58 (3), pp. 355-368 : 363-365

Lasiodactylus kelleri Cline , new species

( Figs. 7, 10, 13 , 16, 19, 22 , 26, 33, 34 , 38, 42 , 44 )

Type Series. Holotype: #, Data Labels : Misiones, San Pedro, Argentina: x-16- 2001, coll. H. Keller, in burrows in soil ; HOLOTYPE, Lasiodactylus kelleri, A.R. Cline des. 2002. Deposited in UNSM . Paratypes: $ (6) # (2), Data Labels: 3 $ with same locality label as Holotype; PARATYPE, Lasiodactylus kelleri, A.R. Cline des. 2002.; one deposited in USNM, one in UNSM, and one LSAM. 3 $ and 3 # specimens with the following locality and data labels: Argentina, Misiones , Departmento Guarinı´ ,

(triangles).

Reserva de Uso Múltiple Guarinı´, 26 8 54 9 S –54 8 12 9 – 18 9 W, interior de selva primaria con sotobosque de bambúseas, interior de madrigueras de Heterogomphus aidoneus Perty , 14-11-2002, PARATYPE, Lasiodactylus kelleri, A.R. Cline des. 2002; three deposited in LSAM and three in UNSM.

Description. Length: 9.6 mm, Width: 4.7 mm, Depth: 2.6 mm. Body uniformly dark reddish brown/black. Dorsum lacking pubescence except for a fringe along the margins of the pronotum and elytra. Head large with prominent mandibles. Labral notch broad and triangular with two convergent setae overlapping within the emargination clypeo-labral suture slightly undulate at anterior margin. Vertex with two large impressed fossae, one on each side of midline. Head densely punctate anteriorly becoming diffusely moderately punctate near posterior margin. Antennal club compact, antennomeres 9 and 10 chevron shaped, and antennomere 11 acutely hexagonal with setal band around middle ( Fig. 7 ). Axillary (supraocular) space reaching anterior margin of eye. Pronotum confusedly, shallowly, minutely punctuate, anterior margin shallowly emarginated, lateral margin broadly tapering to posterior margin, widest near posterior angles, posterior margin slightly emarginate near posterior angles. Scutellum broadly hemispherical with light, small punctures unevenly scattered across surface. Elytral humeri moderately produced, lateral margin narrowly explanate from humeral angle to seven-eighths the length of the elytra, apices broadly rounded, argin finely densely ciliate from humeri to apices, medial suture dark piceous along its entire length. Punctures faint, in serial rows of 2–3 punctures, these rows separated by small raised ridges that bear a series of smaller punctures. Pygidium broadly rounded, almost truncate at apex ( Fig. 13 ), covered with short golden pubescence throughout and along apical margin.

Prosternal process in lateral aspect moderately produced posteriorly over coxae ( Fig. 10 ), in ventral aspect greatly expanded behind procoxae, posterior margin bearing short stiff setae along entire margin. Protibia with sharp lateral curve on inner angle ( Fig. 16 ), apical region expanded, lateral border smooth, medial margin with dense area of small slender spines, central ridge distinct from lateral border with area one-fourth width of tibia between ridge and margin, central ridge bearing row of short setae, also short setae present in area between ridge and lateral margin, apical spine short only as long as first tarsomere. Meso- and metatibia more elongate than either of the other two new species ( Figs. 19 and 22 ) (see Gillogly 1965). Anal sclerite of male genitalia with broad fossa for reception of tegmen ( Fig. 26 ), median notch present along basal margin, dispersed curved setae on apex of sclerite. Tegmen in lateral aspect notched on basal margin ( Fig. 33 ), four long setae originating near base of median lobe fossa on tegmen, sparse short setae on remainder of apex. Median lobe with two large lateral impressions ( Fig. 34 ). Ovipositor with gonocoxites long and slender, fused at basal one-fifth of the coxites ( Fig. 42 ), a few sparse setae present along lateral border of each coxite, terminal gonocoxite appendages borne from large latero-apical pit, each terminal appendage bearing three long setae. Paraprocts sub-cylindrical with medial and lateral borders heavily sclerotized ( Fig. 38 ), apical margin bearing a series of sharp points.

Etymology. The specific epithet honors the collector of the specimens, Hector Keller, who also provided the accounts of the biology of the species.

Diagnosis. The deep inward curvature of the male metatibia, and greatly produced shape of the protibia are all unique characters of this species. Several genitalic features also distinguish this species from any other Lasiodactylus , including: fusion of gonocoxites only along basal one-fifth of the structure, three terminal setae on gonocoxal accessory appendage, sharp projections on apical margin of paraprocts, medial notch of male anal sclerite and recurved setae on apex of this sclerite, deep notch at base of tegmen, and overall structure of median lobe.

Distribution. Known only from the type locality in Misiones, Argentina near San Pedro ( Fig. 44 ).

Biology. The accounts of the biology of L. kelleri are from conversations with Hector Keller, an ethnobotanist from Argentina, who is currently pursuing research on the interactions of dynastine scarabs, food plants, and the native people of the area ( Keller 2003). During his work on scarab-plant interactions, he observed the presence of Lasiodactylus kelleri specimens within burrows constructed by dynastines near damaged plants. Dynastines of the genus Heterogomphus construct burrows near potential food plants, then forage nocturnally at the base of the stalks and on foliage of the plants, in particular the bamboo plant Chusquea ramosissima Lindm. (Poaceae) for H. aidoneus Perty. The scarabs return to their burrows during the day, where they defecate. Keller has found up to 20 specimens of L. kelleri within the confines of these burrows. Thus far, L. kelleri has been found associated with two species of Heterogomphus , namely, H. eteocles Burmeister and H. aidoneus . Species of Heterogomphus are found throughout the range of Lasiodactylus , extending from southern Mexico to Argentina. Direct observation by Keller demonstrated that L. kelleri feeds from the sap flows of the plant stems damaged by the dynastines (see Fig. 43 ). The burrow microhabitat provided by these large herbivorous scarabs represents an ideal refuge for the nitidulids due to its proximity to a food source and protection against predation. This microhabitat and other types of burrow habitats should be more fully explored to discover species that share this interesting association. Keller did not find specimens of L. kelleri in every burrow he examined, suggesting that there may be a successional component to the relationship.

Figures

Figs. 3–13. External characters of Lasiodactylus. 3–4) Maxillary palpi; 3) L. falini; 4) L. centralis. 5–7) Antennomeres 8–11; 5) L. falini; 6) L. centralis; 7) L. kelleri. 8–10) Prosternal process, lateral aspect; 8) L. falini; 9) L. centralis; 10) L. kelleri. 11–13) Pygidium; 11) L. falini; 12) L. centralis; 13) L. kelleri. Scale bar ¼ 0.25 mm for Figures 3–4, 0.5 mm for Figures 5–13.

Figs. 14–22. Tibiae of Lasiodactylus spp. 14–16) Protibia; 14) L. falini; 15) L. centralis; 16) L. kelleri. 17–19) Mesotibia; 17) L. falini; 18) L. centralis; 19) L. kelleri. 20–22) Metatibia; 20) L. falini; 21) L. centralis; 22) L. kelleri. Scale bar ¼ 1.00 mm.

Figs. 23–34. Male genitalia of Lasiodactylus spp. 23–26) Anal sclerite; 23) L. brunneus; 24) L. falini; 25) L. centralis; 26) L. kelleri. 27–34) Tegmen and median lobe; 27–28) L. brunneus; 29–30) L. falini; 31–32) L. centralis; 33–34) L. kelleri. Scale bar ¼ 0.8 mm.

Figs. 35–42. Female genitalia of Lasiodactylus spp. 35–38) Paraprocts; 35) L. brunneus; 36) L. falini; 37) L. centralis; 38) L. kelleri. 39–42) Gonocoxites; 39) L. brunneus; 40) L. falini; 41) L. centralis; 42) L. kelleri. Scale bar ¼ 0.8 mm.

Fig. 44. Distribution of L. falini (squares); L. centralis (circles); L. kelleri (3); and L. brunneus

Fig. 43. Specimens of L. kelleri feeding at a stem sap flow of Chusquea ramosissima Lindm.