Litochropus Casey, 1890

Gimmel, Matthew L., 2013, <strong> Genus-level revision of the family Phalacridae (Coleoptera: Cucujoidea) </ strong>, Zootaxa 3605 (1), pp. 1-147 : 92-93

24. Litochropus Casey, 1890

( Figs. 27 ; 42c, d )

Litochropus Casey 1890: 140 . Type species: Litochropus scalptus Casey 1890 , fixed by monotypy.

Type material. Litochropus scalptus Casey : three syntypes, lectotype here designated to stabilize species name, male with genitalia dissected, “˙ N.C. [=Hot Spring, French Broad River, North Carolina] // CASEY \ bequest \ 1925 // scalptus 2 \ PARATYPE USNM \ 49013 [epithet and numbers handwritten] [red label] // LECTOTYPE ♂ \ Litochropus \ scalptus Casey \ des. M.L. Gimmel 2010 [red label]” ( USNM). Paralectotypes (2 males, USNM), one with similar data to lectotype, another with locality “D.C.”, each with label affixed “ PARALECTOTYPE ♂ \ Litochropus \ scalptus Casey \ det. M.L. Gimmel 2010 [yellow label]”.

Diagnosis. Recognized by the small scutellar shield, lack of protibial ctenidium, protruding metaventral process, metatarsomere I longer than II, mesoventral plate extending posteriorly to metaventral process, and (usually) distinct transverse strigae on elytra.

Description. Very small to medium-sized, total length 1.0– 2.9 mm. Dorsal color solid brunneo-piceous to black ( Figs. 42c, d ), some darker forms with elytral apices lighter. Tibial spur formula 2-2-2 or 2-1-2, tarsal formula 5-5- 5 in both sexes.

Head. Not constricted behind eyes. Eyes small to large; facets flat; interfacetal setae absent; weakly or (rarely) strongly emarginate medially; without posterior emargination; periocular groove absent or (rarely) present; 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 ( Fig. 27b ). Mandible ( Fig. 27a ) with apex bidentate; retinaculum present; mandible without ventral ridge. Maxillary palpomere IV fusiform, nearly symmetrical; galea short, rounded; lacinia with two stout spines. Mentum with sides divergent toward apex; labial palpomere III fusiform. Labrum with apical margin arcuate. Gular sutures short, barely evident.

Thorax. Pronotum with obvious microsetae present, distinct; with weakly to strongly developed scutellar lobe. Prosternum anteriorly with continuous row of marginal setae, setae normal; procoxal cavity with anterolateral notchlike extension; prosternal process rounded to angulate in lateral view, sometimes conspicuously setose preapically, without spinelike setae at apex. Protrochanter without setae; protibia without ctenidium on kickface ( Fig. 27c ). Scutellar shield small. Elytron without spectral iridescence; with one or (sometimes) two sutural striae; disc with rudimentary striae or rows of punctures; with weak to strong transverse strigae; lateral margin with row of tiny, sawtooth-like setae. Mesoventral plate ( Fig. 27f ) notched anteriorly, extending posteriorly to metaventrite, dividing mesoventral disc in two, usually forming procoxal rests; mesanepisternum with complete transverse carina; mesocoxal cavities widely separate, separated by more than half width of a coxal cavity. Mesotarsomere III not bilobed. Metaventral process ( Fig. 27f ) extending to or 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. 27g ) with anterior tendons moderately separated, ventral process intersecting ventral longitudinal flange behind anterior margin. Anterior margin of metacoxa with emargination sublaterally; metacoxal plate with transverse line; metatibial foreface with apical ctenidium roughly perpendicular overall to long axis of tibia; spurs cylindrical, longest spur shorter than or subequal in length to width of tibial apex; metatarsomere I longer than metatarsomere II, joint between I and II rigid ( Fig. 27d ). Hind wing ( Fig. 27e ) 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 oblique 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 with asymmetrical anterior margin and parameres hinged to basal piece, parameres with medial longitudinal division; penis with with paired sclerites and fields of endophallic spicules, apex simple; spiculum gastrale V-shaped, arms free. Female ovipositor weakly sclerotized, palpiform.

Immature stages. Steiner (1977), in an unpublished thesis, illustrated and described the larva and pupa of L. clavicornis .

Bionomics. Litochropus clavicornis larvae, pupae, and adults have been collected and reared from Daldinia fissa C. G. Lloyd (Ascomycota: Xylariaceae ) in Texas ( Steiner 1984; Lawrence 1977, as D. simulans Child ). Litochropus scalptus adults were collected from the stromata of Daldinia concentrica (Bolton) Cesati & de Notaris in Vermont ( Lawrence 1977). Larvae feed on the corky tissue, while adults feed primarily on the spores. I have collected an undescribed species of Litochropus from another species of Xylariaceae (probably Nemania ) in Tennessee.

Distribution and diversity. Most diverse in the New World, where it occurs from Quebec in the north to Bolivia in the south. I have seen specimens only from Cuba in the West Indies. This genus was revised for North America in an unpublished thesis ( Steiner 1977), in which one new species is illustrated and characterized. I have seen a new species from the Great Smoky Mountains of the southern Appalachians, and a large number of species from the Neotropics are undescribed. Litochropus also occurs in eastern and northern Australia, New Guinea, and Borneo. The number of described Old World species is unknown (see discussion).

Included species (6):

Litochropus clavicornis Casey, 1916 ( Distribution : USA) (type!)

Litochropus divergens ( Lea, 1932) , comb. nov. ( Litochrus ) (Distribution: Australia)

Litochropus globulus (Sharp, 1889) , comb. nov. ( Litochrus ) ( Distribution : Panama) (type!)

Litochropus moerens (Guillebeau, 1894) , comb. nov. ( Merobrachys ) ( Distribution : Brazil) (type!)

Litochropus reversus (Sharp, 1889) , comb. nov. ( Litochrus ) ( Distribution : Guatemala) (type!)

Litochropus scalptus Casey, 1890 ( Distribution : Canada, USA) (type!)

Discussion. From the description (including the presence of two sutural striae) and illustrations (metatibia/ tarsus, antenna) of Lea (1932) for his Litochrus divergens , I have determined that this species actually belongs to Litochropus . Additional species described in Litochrus by Arthur Lea (1932) may belong to this genus, but their generic identities will be unknown until examination of types is undertaken.

Figures

FIGURE 27. Litochropus clavicornis, female. (a) Left 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).

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.