Eleodes

Triplehorn, Charles A., Thomas, Donald B. & Rile, Edward G., 2009, The Genus Eleodes Eschscholtz (Coleoptera: Tenebrionidae) In Texas, The Coleopterists Bulletin 63 (4), pp. 413-437 : 415-417

Key to the Eleodes beetles of Texas

As with most keys, and especially in the case of Eleodes , choices within each dichotomy are more reliable when applied to series representing both genders rather than single specimens. Ambiguities which can be anticipated include the size of individual specimens and the conformation of the profemur. Because Eleodes species fall naturally into large or small in size, the first couplet uses a length of 20 mm as the point of separation. The user is advised, however, that this dimension is the nadir of a bimodal distribution rather than an absolute division. The profemur is diagnostic because the males of many species have a preapical tooth on the anterior margin. In such species the females, when lacking the tooth, have the preapical margin distinctly sinuated, as opposed to an even, uninterrupted margin. However, among those species which lack the tooth (or the female sinuation) there are two which have the profemur clavate, which can be mistaken for sinuate. Lastly, it is recommended that once a specimen is determined through the key, the integumental sculpturing be matched against that shown in the illustrations and described in the diagnoses, as that feature tends to be characteristic for most of the species.

1. Larger species, 20 mm or more in length................................. 2

1 9. Smaller species, up to 20 mm in length.................................. 15

2(1). Profemur mutic (unarmed), anteroventral margin entire................ 3

2 9. Profemoral margin sinuate preapically (females) or bearing a prominent preapical tooth (males)........................................ 7

3(2). Elytra caudately produced, more strongly so in males (Figs. 30–31)....................................................... E. caudiferus LeConte

3 9. Elytra not caudate.......................................................... 4

4(3 9). Elytral surface smooth (Figs. 36–37)............... E. longicollis LeConte

4 9. Elytral surface costulate and/or muricate (Figs. 4–6).................... 5

5(4 9). Elytra finely, densely tuberculate, luster dull (Fig. 5)........................................................................ E. neomexicanus Blaisdell

5 9. Elytra with simple or finely muricate punctures, luster shiny.......... 6

6(5 9). Elytra usually with strong asperate spicules on apical declivity along crest of intervals; disc punctate-striate with intervals slightly convex (Fig. 4) (east of Pecos River)...................... E. pedinoides LeConte

6 9. Elytra not asperate on apical declivity, disc usually not striate, or if so, then intervals flat (Fig. 6) (Chisos and Davis Mountains)........................................................... E. wenzeli Blaisdell

7(2 9). Each elytron with sutural and three discal costae (Figs. 26–27)....................................................... E. mirabilis Triplehorn

7 9. Elytra without costae...................................................... 8

8(7 9). Sides of elytra carinate, at least at humeri............................... 9

8 9. Sides of elytra evenly convex............................................. 10

9(8). Pronotal dorsum concave, margins reflexed; sides of elytra carinate for entire length (Fig. 25)................................ E. suturalis (Say)

9 9. Pronotal dorsum convex, margins not reflexed; sides of elytra carinate only near humeri (Fig. 24)................................. E. acutus (Say)

10(8 9). Anterior angles of pronotum acute, usually prominent, often dentiform................................................................... 11

10 9. Anterior angles of pronotum obtuse, rounded (Fig. 23)............................................................................... E. obscurus (Say)

11(10). Elytral punctures simple (caution: the ‘‘ nuptus ’’ form of hispilabris will key here)................................................................... 12

11 9. Elytral punctures often muricate (either strial or intervals or both).. 14

12(11). Abdomen swollen, especially in female, males caudate; pronotum transverse, lateral margins subparallel, not narrowed toward base, widest near middle (Fig. 34)............................. E. spinipes Solier

12 9. Abdomen parallel-sided to ovate; apex caudate or not; pronotum subquadrate, widest in anterior half..................................... 13

13(12 9). Elytral apex caudate (males) or attenuate (females) (Figs. 32–33)............................................................. E. tenuipes Casey

13 9. Elytral apex rounded in both sexes (Fig. 29)......... E. gracilis LeConte

14(11 9). Elytral surface striato-punctate, intervals costate, especially at sides posteriorly (Fig. 28).................................... E. hispilabris (Say)

14 9. Elytral surface irregularly punctate, intervals not costate, sometimes rugose (Fig. 35)........................................ E. sponsus LeConte

15(1 9). Mentum with median carina; antennae long and slender, terminal 4 or 5 segments extending caudad beyond pronotal base; rare, restricted to caves in Big Bend area ( Caverneleodes ).................................. 16

15 9. Mentum without median carina; antennae relatively stout, only 2 or 3 segments extending caudad beyond pronotal base; found in open habitats..................................................................... 17

16(15). Mentum with median longitudinal carina rising abruptly to form conspicuous finger-like process (Fig. 39).......... E. labialis Triplehorn

16 9. Mentum with median longitudinal process only rising slightly anteriorly and with apex acute (Fig. 38)......... E. easterlai Triplehorn

17(15 9) Body distinctly dorso-ventrally compressed; pronotum flattened, about as wide as elytra; elytra broad, flattened, truncate at base, sides abruptly declivent, humeral angles rectangular and prominent (Figs. 3, 15–16, 21–22).................................................... 18

17 9. Body cylindrical; pronotum subquadrate, convex, always narrower than elytra; sides of elytra convex, humeral angles obtuse, not prominent.................................................................. 20

18(17). Base of thorax overlapping base of abdomen; elytra alternately costate (Fig. 3).......................................... E. tricostatus (Say)

18 9. Base of thorax not overlapping base of abdomen; elytra regularly costulate.................................................................... 19

19(18 9). Base of elytra prolonged to embrace thorax laterally (Figs. 15–16) (panhandle)................................................. E. opacus (Say)

19 9. Base of elytra truncate, closely apposed to thorax (Figs. 21–22) (coastal bend)............................................ E. veterator Horn

20(17 9) Anteroventral margin of profemur sinuated preapically (females) or with a tooth (males)....................................................... 21

20 9. Anteroventral margin of profemur unarmed, straight (except males of E. nigrinus and E. arcuatus which have the profemora clavate and preapical margin notably arcuate)....................................... 25

21(20). Elytral surface finely muricate............................................ 22

21 9. Elytral surface smooth, punctate-striate................................. 23

22(21). Integument dull, opaque; basal three protarsomeres of male with pads or tufts of golden setae on plantar surface (Figs. 19–20)..................................................................... E. spiculiferus Triplehorn

22 9. Integument shiny; basal three protarsomeres with open plantar grooves (males may have tuft of setae on basal segment) (Figs. 7– 8).......................................................... E. extricatus (Say)

23(21 9). Elytra with double series of small, closely spaced punctures (Figs. 11– 12).................................................... E. striolatus LeConte

23 9. Elytra with strial punctures uniserial.................................... 24

24(23 9). Elytral striae formed by large, widely spaced dents; integument shiny (Figs. 9–10).................................................. E. goryi Solier

24 9. Elytral striae formed by fine punctures; integument dull (Figs. 17– 18)................................................. E. knullorum Triplehorn

25(20). Elytral surface muricate to granulate, opaque; profemoral margin of males arcuate, often microcrenulate..................................... 26

25 9. Elytral surface smooth, finely punctate, usually shiny; profemoral margin entire............................................................... 27

26(25). Elytra with muricate punctures; size larger, 18–22 mm (Fig. 40).......................................................... E. nigrinus LeConte

26 9. Elytra without muricate punctures; size smaller, 12–16 mm (Figs. 43– 44)........................................................ E. arcuatus Casey

27(25 9). Body fusiform, pronotum widest base to middle; humeral angles of elytra embracing base of pronotum (Figs. 13–14)................................................................................. E. fusiformis LeConte

27 9. Body not fusiform, pronotum widest anterior to middle; humeral angles truncate in apposition to base of pronotum..................... 28

28(27 9). Mentum without prominent middle lobe; body slender, length usually less than 15 mm ........................................................... 29

28 9. Mentum with prominent subtriangular middle lobe directed forward with arcuate apex; body robust, often 15–20 mm in length........... 30

29(28). Pronotum widest in anterior third, anterior margin wider than posterior margin; elytra narrow, more or less parallel-sided (Fig. 41)............................................... E. dissimilis Blaisdell

29 9. Pronotum widest at middle, anterior and posterior margins subequal in width; elytra more or less ovate in dorsal view (Fig. 42)......................................................... E. delicatus Blaisdell

30(28 9) Small, seldom more than 14 mm in length (Fig. 1); protibial spurs in females unequal in size, upper larger than the lower.................................................................................. E. debilis LeConte

30 9. Larger, usually more than 15 mm in length; protibial spurs equal in size in both genders (Fig. 2).......................... E. carbonarius (Say)