Phalacrus Paykull, 1800

Gimmel, Matthew L., 2013, <strong> Genus-level revision of the family Phalacridae (Coleoptera: Cucujoidea) </ strong>, Zootaxa 3605 (1), pp. 1-147 : 53-58

publication ID	https://doi.org/ 10.11646/zootaxa.3605.1.1
publication LSID	lsid:zoobank.org:pub:19CFDC67-4FCB-431D-8BF2-80EEB9EC76A4
persistent identifier	https://treatment.plazi.org/id/8C75C266-101D-2873-2286-F8AE7CA1CC7D
treatment provided by	Felipe
scientific name	Phalacrus Paykull, 1800
status

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12. Phalacrus Paykull, 1800 View in CoL View at ENA

( Figs. 2d View FIGURE 2 ; 3c View FIGURE 3 ; 15 View FIGURE 15 ; 39d, e View FIGURE 39 )

Phalacrus Paykull 1800: 438 View in CoL . Type species: Anisotoma corrusca Panzer 1797 , fixed by subsequent designation.

Glaurosoma Thomson 1859: 66 . Type species: Phalacrus substriatus Gyllenhal 1813 , fixed by original designation. Type material. Anisotoma corrusca Panzer : types not seen.

Phalacrus substriatus Gyllenhal : types not seen.

Diagnosis. One of the few genera that may be unambiguously recognized in dorsal view based on structural characters. The scutellar shield is greatly enlarged relative to most other members of the family, and there is almost always a single sutural stria on the elytron (sometimes extremely reduced or absent). The spiniform ovipositor is an autapomorphy for the genus. Additionally, members have no emargination of the frontoclypeus above the antennal insertion, have metaventral postcoxal lines not separated from the coxal cavities, and have a group of long, stiff setae postero-ventrally near the apex of the femora.

Description. Very small to very large, total length 1.4–4.5 mm. Dorsal color usually pitch black, but a few forms rufotestaceous and some have reddish maculations on the elytra ( Figs. 39d, e View FIGURE 39 ). Tibial spur formula 2-2-2, tarsal formula 5-5- 5 in both sexes.

Head. Not constricted behind eyes. Eyes small; facets convex; interfacetal setae absent; weakly emarginate medially; without posterior emargination; periocular groove present or absent; with transverse setose groove ventrally behind eye. Frontoclypeus ( Fig. 2d View FIGURE 2 ) not or barely emarginate above antennal insertion; clypeal apex arcuate-truncate, but often with asymmetrical emarginations. Antennal club 3-segmented, club symmetrical or weakly asymmetrical; antennomere XI not constricted, often elongate ( Fig. 15b View FIGURE 15 ); males of some Greater Antillean forms with antennae longer than total body length. Mandible ( Fig. 15a View FIGURE 15 ) with apex usually tridentate, middle cusp often quite long and slender, sometimes bidentate (upper cusp lacking) or simple (upper and lower cusps lacking), mandibles often asymmetrical; retinaculum present, strong; mandible without ventral ridge. Maxillary palpomere IV cylindrical, elongate, narrower than palpomere III, nearly symmetrical; galea short, rounded; lacinia with two stout spines. Mentum with sides divergent toward apex; labial palpomere III fusiform. Labrum with apical margin truncate. Gular sutures short, barely evident.

Thorax. Pronotum without obvious microsetae; with scutellar lobe weakly developed. Prosternum anteriorly with continuous row of marginal setae, setae normal; procoxal cavity with anterolateral notchlike extension; prosternal process rounded in lateral view, not conspicuously setose preapically, without row of spinelike setae at apex. Protrochanter with setae; protibia without ctenidium on kickface ( Fig. 15c View FIGURE 15 ). Scutellar shield large, width of raised portion greater than length of eye. Elytron without spectral iridescence; with one sutural stria, stria rarely absent; disc often with rudimentary striae or rows of punctures; without transverse strigae; lateral margin with row of tiny, sawtooth-like setae. Mesoventral plate ( Fig. 15f View FIGURE 15 ) notched anteriorly, not extending posteriorly to metaventrite, forming procoxal rests; mesoventrite sunken medially, not setose; mesanepisternum with complete transverse carina; mesocoxal cavities separated by much greater than half width of a coxal cavity. Mesotarsomere III bilobed. Metaventral process ( Fig. 15f View FIGURE 15 ) extending at least to anterior level of mesocoxae, often highly protruding and lobed anteriorly; metaventral postcoxal lines not separated from mesocoxal cavity margin; discrimen short, extending less than halfway to anterior margin of metaventral process; metendosternite ( Fig. 15g View FIGURE 15 ) with anterior tendons widely separated, ventral process intersecting ventral longitudinal flange at anterior margin. Anterior margin of metacoxa with emargination sublaterally; metacoxal plate with transverse line; metafemur with subapical row of long setae on posteroventral surface; metatibial foreface with apical ctenidium roughly perpendicular overall to long axis of tibia; spurs cylindrical, longest spur much shorter than width of tibial apex; metatarsomere I shorter than metatarsomere II, joint between I and II flexible, tarsomeres with hairy pads similar to those of pro- and mesotarsus ( Fig. 15d View FIGURE 15 ). Hind wing ( Fig. 15e View FIGURE 15 ) with distinct, ovate anal lobe; leading edge without row of long setae at level of RA +ScP; AA 3+4 not apparent except at base, crossvein to Cu absent; cubitoanal system unbranched apically; CuA 2 and MP 3+4 without distal remnants; r4 absent; flecks absent from apical field distal to rpmp2; flecks absent from region just distal to end of radial bar.

Abdomen. Abdominal ventrite I without paired lines or calli; spiracles apparently absent from segment VII; males of some New World forms with medial tufts of setae on some or all ventrites. Male with aedeagus rotated in repose, resting on its side; tegmen ( Fig. 15h View FIGURE 15 ) with asymmetrical anterior margin and parameres either fused to basal piece or separated from (but not hinged to) basal piece by suture, parameres divided longitudinally; penis ( Fig. 15i View FIGURE 15 ) with unpaired endophallic sclerites, apex simple; spiculum gastrale V-shaped, arms free. Female ovipositor ( Fig. 3c View FIGURE 3 ) sclerotized, gonocoxites modified into cornified spinose structures, with 1–3 outwardly directed spines, gonostyli attached subapically.

Immature stages. Friederichs (1908) described the larva of Phalacrus corruscus (Panzer) . Emden (1928) described the larvae of P. grossus Erichson and P. fimetarius (Fabricius) . d’Aguilar (1944) described the larva of P. caricis Sturm. Böving and Craighead (1931) illustrated the larva of the Nearctic P. politus Melsheimer , while the larva of the Australian P. uniformis (Blackburn) was described by Thompson and Marshall (1980).

Bionomics. Members of this genus are highly specialized feeders on smut fungi ( Ustilaginales ) and rust fungi ( Pucciniales ). Level of host specificity is unknown, but Phalacrus species have been recorded from Ustilago (including corn smut, U. maydis (DC.) Cda. ), Sporisorium (including sugarcane smut, S. scitamineum (Sydow) M. Piepenbr., M. Stoll & Oberw. ; see Agarwal [1956]), Tilletia , and Cintractia . Evidence exists ( Agarwal 1956; Ericson et al. 1993) that smut-inhabiting beetles may be aiding in dispersal of their hosts. Adults and larvae of the Australian and introduced New Zealand species Phalacrus uniformis (Blackburn) feed on galls of the rust fungi Uromycladium notabile (Ludwig) McAlpine and U. acaciae (Cooke) Sydow , which infect Acacia mearnsii DeWildemann (see Thompson and Marshall 1980).

Among Australian specimens (mixture of species) with specific host data, Phalacrus specimens have been collected from: Acacia brachybotrya Benth. (Fabaceae) , A. dealbata Link , A. difformis R.T.Baker , A. implexa Benth. , A. paradoxa DC. , A. parramattensis Tindale , A. pendula A.Cunn ex G.Don , Eucalyptus , Melaleuca leucadendra (L.) L. ( Myrtaceae ), and from Sporisorium amphilophis (H.Sydow) Langdon & Full. ( Ustilaginales : Ustilaginaceae ) on grass. Adults are also occasionally collected on flowers, including those of Melaleuca ericifolia Sm. , Leptospermum , and Eucalyptus (all Myrtaceae ) in Australia, and Ligustrum sinense Lour. (Oleaceae) in China. Phalacrus substriatus is often collected on Narthecium ossifragum (L.) Huds. ( Nartheciaceae ) in Europe. Flower-visiting is a somewhat common occurrence among (at least Palearctic) members of this genus.

Distribution and diversity. A morphologically isolated genus, similar only to the related Phalacropsis Casey , and one of only seven genera occurring in both the New and Old Worlds. The range of this genus is essentially coextensive with that of the family as a whole. In the New World, occurs from Alaska (specimens in USNM, certainly the northernmost record for the family in the Western Hemisphere) south to Argentina, including the Greater and Lesser Antilles, with the highest concentration of species in mountainous and xeric areas. In the Old World, it occurs in every region save for the Pacific Islands, though there is a report of a (probably introduced) Phalacrus species occurring in the Hawaiian Islands ( Bowler et al. 1977; Ramsdale and Samuelson 2006). One introduced Australian species, Phalacrus uniformis (Blackburn) , occurs in New Zealand, the only phalacrid known to be established there ( Thompson and Marshall 1980), though a species of Austroporus may also be surviving there.

Included species (96):

Phalacrus acaciae Montrouzier, 1861 (Distribution: New Caledonia)

Phalacrus aethiops Gerstaecker, 1871 (Distribution: Tanzania)

Phalacrus affinis Motschulsky, 1866 (Distribution: Sri Lanka)

Phalacrus alluaudi Guillebeau, 1896 ( Distribution : Madagascar) (type!)

Phalacrus americanus Guillebeau, 1894 ( Distribution : United States) (type!)

Phalacrus apicalis Guillebeau, 1894 ( Distribution : Tanzania) (type!)

Phalacrus arizonicus Casey, 1916 ( Distribution : United States) (type!)

Phalacrus aterrimus Wollaston, 1867 (Distribution: Cape Verde, Senegal)

Phalacrus atrolucens Casey, 1916 ( Distribution : United States) (type!)

Phalacrus atticus Guillebeau, 1894 (Distribution: Greece)

Phalacrus bataviensis Champion, 1925 ( Distribution : Indonesia) (type!)