Ischyrus quadripunctatus quadripunctatus (Olivier 1792)

Skelley, Paul E., 2009, Pleasing fungus beetles of the West Indies (Coleoptera: Erotylidae: Erotylinae), Insecta Mundi 2009 (82), pp. 1-94 : 49-53

Ischyrus quadripunctatus quadripunctatus (Olivier 1792)

Figure 1b , 11 , 19, 23 , 75, 78

Erotylus quadripunctatus Olivier 1792: 431 , 437.

Mycotretus quadripunctatus (Olivier) ~ Dejean 1836: 429; Dejean 1837: 453.

Ischyrus quadripunctatus (Olivier) ~ Lacordaire 1842: 127-128.

Ischyrus quadripunctatus Crotch 1873b: 144 ~ Gemminger and Harold 1876: 3690.

Ischyrus quadripunctatus quadripunctatus (Olivier) ~ Boyle 1954: 39-41.

Micrischyrus quadripunctatus quadripunctatus (Olivier) 1792 ~ Alvarenga 1994: 16.

Engis variegata Dejean 1821: 45 [nomen nudum] ~ Gemminger and Harold 1876: 3691 [catalog].

Mycotretus variegata (Dejean) ~ Dejean 1836: 429; Dejean 1837: 453.

Mycotretus humeralis Chevrolat in Dejean 1836: 429 [nomen nudum] ~ Dejean 1837: 453; Sturm 1843: 305.

Ischyrus subcylindricus Lacordaire 1842: 117-118 ~ Skelley 1998b: 51.

Mycotretus subcylindricus Chevrolat in Dejean 1836: 429 [nomen nudum] ~ Dejean 1837: 453; Lacordaire 1842: 117-118.

Micrischyrus subcylindricus (Lacordaire) ~ Alvarenga 1994: 16.

Ischyrus graphicus Lacordaire 1842: 125-126 ~ Skelley 1998b: 51.

Ischyrus quadripunctatus graphicus Lacordaire ~ Boyle 1954: 41-43.

Micrischyrus quadripunctatus graphicus (Lacordaire) ~ Alvarenga 1994: 15.

Ischyrus quadripunctatus var. alabamae Schaeffer 1931: 175 ~ Mader 1938: 19.

Ischyrus quadripunctatus var. antedivisa Mader 1938: 19 ~ Boyle 1954: 39-41.

Ischyrus quadripunctatus Var. A Lacordaire 1842: 127-128 .

Ischyrus puncticollis Gorham 1887: 44-45 ~ Skelley 1998b: 51.

Micrischyrus puncticollis (Gorham) ~ Alvarenga 1994: 15.

Ischyrus quadripunctatus chiasticus Boyle 1954 ~ Skelley 1998b: 51, 56.

Ischyrus chiasticus Boyle 1954: 43-46 .

Micrischyrus chiasticus (Boyle) ~ Alvarenga 1994: 13.

Diagnosis. Ischyrus quadripunctatus is easily recognized by: a color pattern with 4 central pronotal spots in a transverse arch ( Fig. 11 , 75 ), club antennomeres asymmetrical, and terminal maxillary palpomeres narrowed and distinctly asymmetrical ( Fig. 19 ).

Description. Length: 4.8-8.8 mm; width: 2.3-3.7 mm. Body elongate, widest at basal third of elytra; variably microreticulate, dull to glossy; dorsal coloration primarily orange with black marks, ventral coloration primarily black with orange marks on lateral abdomen and prothorax; head black with variably sized anterior orange mark; pronotal pattern based on 4 free discal spots in transverse anteriorly concave arch, base with variable black marking on median half, anterior margin narrowly black between eyes; elytron with orange epipleural fold, variable basal, medial and apical transverse black bands; legs entirely black or banded with orange; tarsi dark brown to black; palpi pale brown to black; antennae brown, club black.

Head interocular width = 2.0-2.5 x ocular width; vertex puncture size = an ocular facet diameter, separated 1-3 x their diameter; epistome puncture size = 0.5-0.75 x ocular facet diameter, separated by 1 x their diameter; stridulatory files present on males. Antenna attaining basal quarter of pronotum; antennomere III as long as antennomeres IV-VI combined; antennomeres X-XI asymmetrical; antennomere X angled at base; antennomere XI transverse. Terminal maxillary palpomere triangular, narrowed, longer than wide, width = 0.8 x length. Terminal labial palpomere triangular, extended on medial side, narrow, width = 0.8 x length. Labial palp width = 0.75 x maxillary palp width. Mentum with plate broadly triangular, length = 0.7 x basal width.

Pronotal disc puncture size = an ocular facet diameter, separated by 1-3 x their diameter. Scutellum pentagonal, length = 0.5 x width. Elytron strial puncture size = pronotal disc puncture; interval puncture size = 0.20-0.25 x strial puncture diameter.

Prosternum weakly keeled and pinched anteriorly, weakly concave to flattened posteriorly; length = 2 x intercoxal width; coxal lines straight, not continuous around coxal cavity; base shallowly concave. Mesosternum coxal lines straight to slightly arched; base sinuate, medially lobed. Metasternum long, distance between meso- and metacoxae = 1.8-2.0 x intermesocoxal width; coxal lines short, attaining less than 0.25 distance to posterior lateral angle; metasternum finely punctate medially, few shallow coarse lateral punctures. Abdomen with metacoxal lines often continuous around coxal cavity, some with coxal line attaining half distance to posterior edge; surface with coarse punctures laterally, fine punctures medially. Male genitalia with median lobe moderately arched, apically truncate, slightly constricted just before tip; internal sac without noticeable sclerotized structures; flagellum long and narrow, flattened and ribbon-like at basal half ( Fig. 78 ).

Distribution. Found from Canada, through continental North, Central, and South America to Argentina and Paraguay. In the Caribbean, I. quadripunctatus occurs on a few of the lower Lesser Antilles, i.e. St. Lucia ( Skelley 1998b) and St. Vincent ( Gorham 1898: 335, Leng and Mutchler 1914: 412, both as I. graphicus ) ( Fig. 1b ).

Type Material. The repository for the type of Erotylus quadripunctatus is unknown. The identity of the species is based on early illustrations and type localities ( Skelley 1998b).

Specimens Examined. Many specimens of I. quadripunctatus were studied in addition to the 3186 studied for the revision of Ischyrus ( Skelley 1998b) . Only 5 were from the West Indies and have the

following label data: St. Lucia, Union Agric. Sta., 25-V-1987, R. E. Woodruff, blacklight (1- FSCA) ; St. Vincent, H. H. Smith (4- NHML) .

Variation. Ischyrus q. quadripunctatus varies clinally in color pattern across its range ( Skelley 1998b). The pattern variation that occurs in the Lesser Antilles has the head with an orange central spot, legs entirely black, and base of the pronotum with 3 tooth-like spots. The central tooth-like spot connects with 2 “free” central spots on the pronotal disc ( Fig. 11 , 75 ).

Remarks. For a more complete list of references, specimens studied, and comments on biology, see Skelley (1998b).

Figures

Figure 1. West Indian maps. 1a) Map of West Indian countries mentioned in the text. 1b) Map indicating species occurring on specific islands with distribution of Notaepytus flavitarsis (Lacordaire) indicated by the white triangles.

Figure 2-11. Key characters. 2-3) Anterior view of head and pronotum. 2) Iphiclus suturalis. 3) Notaepytus flavitarsis. 4-5) Lateral habitus. 4) Aegithus clavicornis. 5) Iphiclus suturalis. 6-11) Dorsal habitus. 6) Aegithus clavicornis. 7) Aegithus lebasii. 8) Iphiclus guadeloupensis. 9) Iphiclus suturalis. 10) Cubyrus sapphirus. 11) Ischyrus quadripunctatus.

Figure 18-25. Key characters. 18-21) Mesofemur. 22-25) Antenna. 18, 22) Cubyrus sapphirus. 19, 23) Ischyrus quadripunctatus. 20, 24) Epytus cyaneus. 21, 25) Notaepytus flavitarsis.[White arrow points at posterior marginal bead, or note its absence, on mesofemur.]

Figure 73-78. Dorsal habitus and genitalia. 73, 76) Cubyrus sapphirus, paratype (genitalia from Skelley 1998b). 74, 77) Epytus cyaneus. 75, 78) Ischyrus quadripunctatus (genitalia from Skelley 1998b). Genitalic sale lines = 0.66 mm.