Neolitochrus Gimmel, 2013

Gimmel, Matthew L., 2013, <strong> Genus-level revision of the family Phalacridae (Coleoptera: Cucujoidea) </ strong>, Zootaxa 3605 (1), pp. 1-147 : 95-97

25. Neolitochrus Gimmel , gen. nov.

( Figs. 28 ; 42h, i )

Type species: Litochrus pulchellus LeConte 1856 , here designated.

Type material. Litochrus pulchellus LeConte : holotype, “[orange disc (=Southern states, Gulf states)] // Type \ 6657 [red label, number handwritten] // Litochrus \ pulchellus \ Lec. [handwritten] // HOLOTYPE \ Litochrus \ pulchellus LeConte \ det. M.L. Gimmel 2010 [red label]” ( MCZ), point mounted.

Diagnosis. Recognized by the lack of a protibial ctenidium, presence of one or two elytral striae, small scutellar shield, metatarsomere I longer than II, lack of spectral iridescence on elytra, and metaventral plate not extending posteriorly to metaventral process.

Description. Very small to medium-sized, total length 0.9–2.3 mm. Dorsal color highly variable, some darker forms with yellowish or reddish maculations ( Figs. 42h, i ). Tibial spur formula 2-2-2 (appearing 1-1- 1 in an undescribed species from Haiti), tarsal formula 5-5- 4 in males, 5-5- 5 in females.

Head. Not constricted behind eyes. Eyes medium-sized to large; facets convex; interfacetal setae absent; strongly emarginate medially; without posterior emargination; periocular groove absent or (rarely) present and weak; with transverse setose groove ventrally behind eye. Frontoclypeus emarginate above antennal insertion; clypeal apex arcuate-truncate. Antennal club 3-segmented, club weakly asymmetrical; antennomere XI not constricted or constricted on anterior aspect only ( Fig. 28b ). Mandible ( Fig. 28a ) with apex bidentate; retinaculum absent; mandible without ventral ridge. Maxillary palpomere IV fusiform, short, nearly symmetrical; galea short, rounded; lacinia with two stout spines. Mentum with sides divergent toward apex; labial palpomere III extremely short, round, as wide as long to slightly longer than wide. Labrum with apical margin arcuate. Gular sutures short, barely evident .

Thorax. Pronotum with obvious microsetae present, distinct; with weakly to moderately developed scutellar lobe. Prosternum anteriorly with marginal row of setae discontinuous, with gap medially, setae normal; procoxal cavity with anterolateral notchlike extension; prosternal process rounded in lateral view, not conspicuously setose preapically, without spinelike setae at apex. Protrochanter without setae; protibia without ctenidium on kickface ( Fig. 28c ). Scutellar shield small. Elytron without spectral iridescence, though usually with microsculpture-induced iridescence; with two or (sometimes) one sutural striae; disc usually devoid of rudimentary striae or rows of punctures; sometimes with weak transverse strigae; lateral margin with row of tiny, sawtooth-like setae. Mesoventral plate ( Fig. 28f ) notched anteriorly, lateral borders becoming obscured posteriorly, incomplete, not extending to mesocoxal cavities or mesoventral process, not forming procoxal rests; mesoventral disc sunken medially, asetose; mesanepisternum with complete transverse carina; mesocoxal cavities widely separate, separated by more than half width of a coxal cavity. Mesotarsomere III bilobed. Metaventral process ( Fig. 28f ) extending beyond anterior level of mesocoxae, sometimes protruding and arcuately lobed anteriorly; metaventral postcoxal lines narrowly or not at all separated from mesocoxal cavity margin, smoothly arcuate; discrimen short, extending less than halfway to anterior margin of metaventral process; metendosternite ( Fig. 28g ) with anterior tendons moderately separated, ventral process intersecting ventral longitudinal flange behind anterior margin. Anterior margin of metacoxa without emargination sublaterally; metacoxal plate with transverse line; metatibial foreface with apical ctenidium roughly perpendicular overall to long axis of tibia; spurs cylindrical, longest spur distinctly longer than width of tibial apex; metatarsomere I longer than metatarsomere II, joint between I and II rigid ( Fig. 28d ). Hind wing ( Fig. 28e ) with distinct, ovate anal lobe; leading edge with complete row of long setae at level of RA +ScP; AA 3+4 absent; cubitoanal system unbranched apically; CuA 2 and MP 3+4 without distal remnants; r4 absent; flecks absent from apical field distal to rp-mp2; long transverse proximal sclerite and weak irregular sclerite present just distal to end of radial bar.

Abdomen. Abdominal ventrite I without paired lines or calli; spiracles present and apparently functional on segment VII. Male with aedeagus upright in repose; tegmen ( Fig. 28h ) with asymmetrical anterior margin and parameres hinged to basal piece, parameres with or without medial longitudinal division; penis ( Fig. 28i ) with with paired sclerites and fields of endophallic spicules, apex simple or weakly bilobed; spiculum gastrale V-shaped, arms free. Female ovipositor weakly sclerotized, palpiform.

Immature stages. Unknown.

Bionomics. Members of this genus have been collected by beating and often come to lights at night in numbers. Their feeding habits remain poorly known, although they are probably feeders on ascomycete fungi.

Distribution and diversity. Occurring in the New World from at least New Jersey, Illinois, and Arizona in the north to Bolivia, Paraguay, and Brazil (Santa Catarina) in the south. I have seen specimens from the Bahamas, Cuba, and Hispaniola in the West Indies. The Neotropical region contains a large number of undescribed species. I have seen specimens from Thailand (HIC) that appear to belong to this genus.

Included species (5):

Neolitochrus aterrimus (Casey, 1890) , comb. nov. ( Litochrus ) ( Distribution : USA) (type!)

Neolitochrus crucigerus (Casey, 1890) , comb. nov. ( Litochrus ) ( Distribution : USA) (type!)

Neolitochrus immaculatus (Casey, 1890) , comb. nov. ( Litochrus ) ( Distribution : USA) (type!)

Neolitochrus mexicanus (Guillebeau, 1894) , comb. nov. ( Heterolitus ) (Distribution: Mexico) (type!) Neolitochrus pulchellus (LeConte, 1856) , comb. nov. ( Litochrus ) (Distribution: USA) (type!)

Discussion. In the Neotropical Region some species (recognized dorsally by a nebulous transverse dark band across the elytra) exhibit body forms that are virtually opisthognathous. They also possess an abnormally acute metaventral process and a narrow prosternal process. Upon further study this group of species may warrant generic status. At 0.9 mm, Neolitochrus contains the smallest known phalacrids.

Etymology. Derived from the Greek neos (new) and the phalacrid genus Litochrus , with which this genus was formerly confused. The gender of the name is masculine.

Figures

FIGURE 28. Neolitochrus pulchellus, male. (a) Right mandible, dorsal; (b) left antenna (scale bar = 0.5 mm). (c) Left protibia and tarsus, dorsal; (d) left metatibia and tarsus, ventral (scale bar = 0.5 mm). (e) Hind wing (scale bar = 1.0 mm). (f) Meso- and metaventrite, ventral (scale bar = 0.5 mm). (g) Metendosternite (scale bar = 0.5 mm). (h) Tegmen, ventral; (i) penis, ventral (scale bar = 0.5 mm).

FIGURE 42. Photographs. Grouvelleus n.sp., Africa: (a) dorsal; (b) ventral. Litochropus n.sp.: (c) dorsal; (d) ventral. Litochrus sp.: (e) dorsal; (f) ventral. Malagophytus steineri, holotype: (g) dorsal. Neolitochrus pulchellus: (h) dorsal; (i) ventral.