Silphidae

Mullins, Patricia L., Riley, Edward G. & Oswald, John D., 2013, Identification, distribution, and adult phenology of the carrion beetles (Coleoptera: Silphidae) of Texas, Zootaxa 3666 (2), pp. 221-251 : 223-224

Key to the adult Silphidae of Texas

1 Elytra shorter, truncate, exposing 3 or 4 abdominal terga, usually with irregular red or orange maculae ( Figs. 24–30 ); fifth abdominal tergum with stridulatory files; head with epistomal suture present ( Fig. 1 ); second antennomere small, indistinct, hidden in tip of first antennomere ( Fig. 2 ). ( Nicrophorinae : Nicrophorus )........................................ 7

- Elytra longer, usually not truncate, at most exposing 1 or 2 abdominal terga, usually without large colored maculae ( Figs. 18– 23 ); fifth abdominal tergum lacking stridulatory files; head with epistomal suture absent ( Fig. 3 ); second antennomere distinct, not hidden in tip of first antennomere ( Fig. 4 ). ( Silphinae ).................................................... 2

2(1-) Pronotum widest toward base ( Fig. 6 ); elytra immaculate; hind femur of male not swollen and without spines............. 3

- Pronotum orbicular, widest toward middle ( Fig. 5 ); elytra with small red maculae before apex; hind femur of male swollen, with one or two spines. Habitus: Fig. 19 ......................................... Necrodes surinamensis (Fabricius)

3(2) Head with a row of long erect hairs behind eyes; elytral disc with rugose to rugulose sculpturing, at least distally, and with dis- tinct costae ( Figs. 18, 20–22 )........................................................................... 4

- Head without a row of long erect hairs behind eyes; elytral disc smooth, without costae. Habitus: Fig. 23 .............................................................................................. Thanatophilus truncatus (Say)

4(3) Elytral epipleuron without aeneous luster or short golden hairs; pronotum entirely black, or with a black median macula and red-orange margins; elytral disc distally with weak rugulose sculpturing ( Figs. 20–22 ). ( Oiceoptoma ).................. 5

- Elytral epipleuron with aeneous luster and short golden hairs; pronotum with a black median macula and yellow margins; ely- tral disc uniformly rugose. Habitus: Fig. 18 ....................................... Necrophila americana (Linnaeus)

5(4) Pronotum entirely black ( Figs. 20, 22 ).................................................................... 6

- Pronotum black with red-orange margins. Habitus: Fig. 21 ........................ Oiceoptoma noveboracense (Forster)

6(5) Elytral epipleuron wide in posterior half ( Fig. 7 ), with upper oblique portion twice width of lower vertical portion; elytral inter- vals distally with weak rugulose sculpturing. Habitus: Fig. 20 ........................ Oiceoptoma inequale (Fabricius)

- Elytral epipleuron narrow in posterior half ( Fig. 8 ), with upper oblique portion approximately equal in width to lower vertical portion; elytral intervals distally with weak to strong rugulose sculpturing. Habitus: Fig. 22 ...................................................................................................... Oiceoptoma rugulosum Portevin

7(1) Pronotum with anterior transverse impression, lateral margins not exceptionally narrow ( Fig. 10 ); elytral epipleuron wide.. 8

- Pronotum without anterior transverse impression, lateral margins extremely narrow ( Fig. 9 ); elytral epipleuron narrow. Habi- tus: Fig. 25 ................................................................ N icrophorus carolinus (Linnaeus)

8(7) Frons and pronotal disc black; tarsal empodium bisetose ( Fig. 12 ).............................................. 9

- Frons and pronotal disc red ( Fig. 10 ); tarsal empodium quadrisetose ( Fig. 11 ). Habitus: Fig. 24 ..................................................................................................... Nicrophorus americanus Olivier

9(8) Pronotum glabrous, or with sparse hairs on anterior or lateral margins............................................ 10

- Pronotum with dense yellow pubescence. Habitus: Fig. 30 ............................ Nicrophorus tomentosus Weber

10(9) Posterior lobe of metepimeron glabrous or with dark hairs (or only a few yellow hairs) ( Fig. 15 ); pronotum variable ( Figs. 16– 17 )............................................................................................... 11

- Posterior lobe of metepimeron covered with dense yellow pubescence ( Fig. 13 ); pronotum cordate, widest anteriorly ( Fig. 14 ). Habitus: Fig. 26 ............................................................ Nicrophorus marginatus Fabricius

11(10) Dorsal surface of elytra without long hairs ( Fig. 13 ); epipleural ridge extended almost to humeral callus................ 12

- Dorsal surface of elytra with long fine hairs, especially laterally ( Fig. 15 ); epipleural ridge obliterated well before humeral cal- lus. Habitus: Fig. 29 .............................................................. Nicrophorus orbicollis Say

12(11) Epipleuron entirely black; dorsal elytral maculation inconspicuous. Habitus: Fig. 28 ....... Nicrophorus pustulatus Herschel

- Epipleuron mostly orange with anterior black macula; dorsal elytral maculation conspicuous. Habitus: Fig. 27 ...................................................................................... Nicrophorus mexicanus Matthews

Figures

FIGURES 24 – 30. Habitus of Texas Nicrophorus. 24, N. americanus; 25, N. carolinus; 26, N. marginatus; 27, N. mexicanus; 28, N. pustulatus; 29, N. orbicollis; 30, N. tomentosus. All scale bars = 10 mm.

FIGURES 1 – 6. Details of Texas Silphidae. 1. Nicrophorus pustulatus, presence of epistomal suture; 2. Nicrophorinae, antenna; 3. Necrophila americana, absence of epistomal suture; 4. Silphinae, antenna; 5. Necrodes surinamensis, pronotum; 6. Oiceoptoma inaequale, pronotum.

FIGURES 18 – 23. Habitus of Texas Silphidae. 18, Necrophila americana; 19, Necrodes surinamensis; 20, Oiceoptoma inaequale; 21, O. noveboracense; 22, O. rugulosum; 23, Thanatophilus truncatus. All scale bars = 10 mm.

FIGURES 7 – 11. Details of Texas Silphidae. 7. Oiceoptoma inaequale, ventral view, wide elytral epipleuron; 8. Oiceoptoma rugulosum, ventral view, narrow elytral epilpeuron; 9. Nicrophorus carolinus, pronotum; 10. Nicrophorus americanus, pronotum; 11. Nicrophorus americanus, tarsal empodium quadrisetose.

FIGURES 12 – 17. Details of Texas Silphidae. 12. Nicrophorus tomentosus, tarsal empodium bisetose; 13. Nicrophorus marginatus, yellow pubescence of posterior lobe of metepimeron, no hairs on dorsal surface of elytra; 14. Nicrophorus marginatus, pronotum. 15. Nicrophorus orbicollis, posterior lobe of metepimeron glabrous, long hairs on dorsal surface of elytra; 16. Nicrophorus pustulatus, pronotum; 17. Nicrophorus mexicanus, pronotum.