Praocis (Praocis) Eschscholtz, 1829

Flores, Gustavo E. & Pizarro-Araya, Jaime, 2012, Systematic revision of the South American genus Praocis Eschscholtz, 1829 (Coleoptera: Tenebrionidae). Part 1: Introduction and subgenus Praocis s. str., Zootaxa 3336, pp. 1-35 : 5-9

Subgenus Praocis (Praocis) Eschscholtz, 1829

Praocis Eschscholtz, 1829: 6 .

Praocis (Praocis) : Solier, 1840: 220; Solier, 1851: 186; Lacordaire, 1859: 213; Kulzer, 1958: 11 (rev.); Peña, 1966: 428 (cat.); Vidal & Guerrero, 2007: 73, 212; Flores, 2007: 411, 416.

Redescription. Length 5.0–14.0 mm; habitus elongate to oval, flattened or convex; body glabrous or with short setae. Colour of body and legs black to dark brown, antennae dark brown.

Head. Clypeus with anterior margin concave, extending anterior to lateral expansion of frons, width of anterior margin not exceeding half the width of interocular distance; clypeal suture not covered by frons, clypeus and frons at same level; frons with round punctures, lateral expansion rounded ( Fig. 1 ); antennae equal in length in both sexes; antennomere 10 wider than long, antennomere 9 longer than antennomere 10, antennomere 11 longer than antennomere 10 ( Fig. 2 ); apical tomentose sensory patches on antennomere 9 in two areas subequal in size, on antennomere 10 in a semicircle dorsally continuous, on antennomere 11 on distal half ( Fig. 2 ).

Thorax. Pronotum with round punctures, lacking carinae or striae; prosternum with a narrow, well defined edge on anterior margin. Proepisternum, mesepisternum, and metepisternum with protuberances. Proepisternum with shallow grooves not reaching superior margin. Metasternum with punctures.

Elytron convex, surface punctate, lateral margin well defined with a fine edge, epipleuron conspicuous throughout, with edge, anterior margin reaching elytral humeri and posterior angle of pronotum, anterior quarter four times as wide as posterior half.

Legs. Distance between meso– metacoxae exceeding half mesocoxal length. Ventral surface of profemora with a row of setae on anterior edge. Protibiae explanate, apical process concave from behind, inner and outer margins armed with a row of contiguous spines, outer margin concave ( Fig. 5 ), anterior face with long, fine setae; posterior face of protibiae and outer face of meso– and metatibiae with short, stout setae. Ventral surface of tarsi bearing sparse decumbent setae.

Male genitalia ( Figs 6 − 9 ). Dorsal membrane of proctiger concave, with two sclerotized areas. Basal lamina of tegmen long (B/E> 1.0) ( Figs 6, 8 ). Lateral styles of tegmen distally close, with apex narrow, with setae on ventral surface and lateral margins ( Figs 7, 9 ), and not overlapping median lobe dorsally. Median lobe tubulous, one third width of lateral styles of tegmen ( Figs 6, 8 ).

Female genitalia ( Fig. 10 ). Spiculum with arms “V”-shaped. Paraprocts with setae; coxites with setae, basal lobe of coxite not extended over paraproct, midventral sclerite distally broadened. Vagina saccate. Spermathecal accesory gland longer than vagina, with duct not annulate. Spermatheca with six basal tubes or less, all similar in width and branching pattern.

Geographic distribution. The species of Praocis s. str. are endemic to central and southern Chile and occur from 26º South (Atacama Region, Quebrada el León) to 42º South (Los Lagos Region, Carelmapu) in the biogeographic provinces of Atacama, Coquimbo, Santiago, Maule and Valdivian Forest ( Morrone 2006).

Habitat. The distribution range of the subgenus extends from the sea level to an altitude of ~ 1300 m. Most species are distributed between the Huasco coastal desert and the coastal steppe shrub ( Gajardo 1994), with 4 and 10 species each one and are ecologically related to shrubby and herbaceous vegetation (perennial and annual) characteristic of the Chilean Coastal Desert (CCD) such as Frankenia chilensis K. Presl (Frankeniaceae) , Nolana brunonianus Hook. et. Arn, Nolana sedifolia Poepp. (Nolanaceae) , Haplopappus foliosus DC. ( Asteraceae ), Cristaria glaucophylla Cav. (Malvaceae) , Leucocoryne dimorphophetala (Gay) (Alliaceae) , Adesmia littoralis Burkart (Papilionaceae) , and Alstroemeria leporina Ehr. (Alstroemeriaceae) . One species ( Praocis (P.) costata ) inhabits deciduous woodlands of Nothofagus obliqua , N. alpina , and Aextoxicon punctatum ( Gajardo 1994) in the Valdivian Forest biogeographic province ( Morrone 2006).

Biology. Adults are epigean and phytophagous, have diurnal habits and bury underground or hide under stones or shrubs in the hours of highest solar radiation. They are found mainly on coastal terraces, plains, and basins of the longitudinal valley of the CCD. One of us (JPA) collected Praocis bicentenario sp. nov. walking during the daytime on dunes and eating flowers and leaves of Scirpus americanus (Cyperaceae) and Chorizanthe paniculada (Polygonaceae) in the Choapa Province (Coquimbo Region, Chile).

Laboratory observations on oviposition: eggs are laid on the substrate surface –mainly sand– or at a depth ranging from 5 to 10 cm. Larval development is hypogeous and occurs mainly in protected places, e.g., under bark or rocks, and on sandy soils containing roots or rotting wood (J. Pizarro-Araya pers. obs.). The behavior of Praocis (Praocis) spinolai Gay & Solier and Praocis (Praocis) tibialis Gay & Solier 1840 shows that eggs are laid in groups of 5 to 7, with a maximum of 6 ovipositions. These data agree with reports by Pizarro-Araya et al. (2005, 2007) on Gyriosomus Guérin-Méneville , a genus of Tenebrionidae Pimeliinae sympatric with Praocis .

Ecology. Some studies on coleopteran communities have documented the presence of species of the genus Praocis in central Chile and provided details about their distribution. Sáiz & Campalans (1984) and CepedaPizarro (1989) studied the relationship between the assemblage of epigean coleopterans and plant communities; Cepeda-Pizarro et al. (1996) examined the relationship between the body size of tenebrionids and biomass, and Vergara et al. (2006) related the distribution patterns of coleopteran species to protected areas.

Alfaro et al. (2009) documented the taxonomic diversity of epigean tenebrionids on the Choros Archipelago (Coquimbo Region). They recorded fourteen species from eight genera, and Praocis (Praocis) spinolai Gay and Solier was the second most abundant, making up 17% of the total capture. Praocis was the most diverse genus of Tenebrionidae , with four sympatric species from three subgenera in all three islands associated mainly to dune systems, where they captured larvae of the genera Praocis and Gyriosomus at different stages of development. The preference for sandy places by species of these two genera agrees with observations by Pizarro-Araya et al. (2005, 2007) showing that such habitats allow for deeper ovipositions ( Alfaro et al. 2009; Pizarro-Araya 2010).

Key to species of the subgenus Praocis s. str.

1. Pronotum widest at midpoint ( Fig. 15 ), lateral margin with a horizontal, outer groove bearing a row of long, golden setae, dorsal surface of lateral margin lacking a row or tuft of setae; prosternum convex, with edge on anterior margin of equal width throughout, lacking prosternal process ( Fig. 11 )................................... P. (Praocis) costata Gay & Solier

- Pronotum widest behind midpoint ( Figs. 16 − 26 ), lateral margin lacking horizontal outer groove and without setae, dorsal surface of lateral margin bearing a row or tuft of short, golden setae ( Fig. 3 ); prosternum horizontal, with edge on anterior margin broadened below gula, prosternal process subrectangular forming a straight angle or produced backwards ( Figs. 12 − 14 )...... 2

2. Apical tomentose sensory patches on antennomere 9 arranged in two areas contiguous dorsally ( Fig. 2 ); antennomere 10 wider than antennomere 11 ( Fig. 2 ); prosternum and mesosternum with protuberances; prosternal process subrectangular forming a straight angle, not produced backwards ( Fig. 12 ); pseudopleuron with setae arising on protuberances..................... 3

- Apical tomentose sensory patches on antennomere 9 arranged in two areas separated dorsally; antennomere 10 as wide as antennomere 11; prosternum and mesosternum with punctures; prosternal process produced backwards ( Figs. 13–14 ); pseudopleuron glabrous or with setae arising on punctures..................................................... 6

3. Antennomere 9 longer than wide; pronotum with lateral quarters flat, dorsal surface of lateral margin bearing a row of long, golden setae ( Fig. 3 ); elytron with four longitudinal grooves bearing fine, golden setae ( Fig. 16 )............................................................................................. P. (Praocis) sanquinolenta Gay & Solier

- Antennomere 9 wider than long ( Fig. 2 ); pronotum with lateral quarters convex, dorsal surface of lateral margin bearing a tuft of long, golden setae; elytron with two to four longitudinal grooves bearing broad, golden, scaly setae ( Fig. 4 )............... 4

4. Pronotum with disc glabrous, width of anterior margin not exceeding half the width of posterior margin; elytron with four longitudinal grooves bearing setae, grooves wider than intervals, inner groove parallel with the inner groove of the other elytron; metatibiae straight......................................................... P. (Praocis) quadrisulcata Germain

- Pronotum with disc bearing fine golden setae, width of anterior margin exceeding half the width of posterior margin; elytron with two or three longitudinal grooves bearing setae, intervals wider than grooves, inner groove converging at the apex with the inner groove of the other elytron ( Fig. 17 ); metatibiae curved outward ( Fig. 17 )........................................ 5

5. Pronotum with posterior angles right; elytron with three longitudinal grooves bearing setae, inner groove from apex of elytron surpassing the midpoint of elytron towards anterior, medial and outer grooves from apex of elytron reaching the base towards anterior, intervals arched....................................................... P. (Praocis) rufipes Eschscholtz

- Pronotum with posterior angles acute; elytron with two longitudinal grooves bearing setae, inner groove from apex of elytron reaching only the posterior third, not surpassing the midpoint of elytron towards anterior, outer groove wider than inner, from apex of elytron reaching the base towards anterior and broadened in central part, intervals flat ( Fig. 17 )................................................................................................. P. (Praocis) bicentenario sp. nov.

6. Elytron with dorsal surface bearing two kinds of golden setae: some short, broad, scaly, dense, and others long, finer, twice or three times longer than scaly setae, sparse or forming tuft; setae disperse or arranged into three longitudinal grooves............ 7

- Elytron with dorsal surface glabrous or bearing only short, broad, golden, scaly setae disperse or arranged into three or four longitudinal grooves on dorsal surface or one groove over lateral margin ( Fig. 4 ).................................. 8

7. Elytron rugose with three longitudinal grooves well demarcated, grooves wider than intervals, with two kinds of setae abundant on dorsal surface or arranged into three grooves visible over entire surface ( Fig. 18 )............ P. (Praocis) hirtella Kulzer

- Elytron punctured with three longitudinal grooves weakly demarcated, intervals wider than grooves, with two kinds of setae disperse on dorsal surface or arranged into three grooves visible on posterior half ( Fig. 19 ) P. (Praocis) subsulcata Gay & Solier

8. Elytron with three or four longitudinal grooves on dorsal surface or one groove over lateral margin; grooves bearing abundant or sparse short, broad, golden, scaly setae ( Figs 20–22 ).......................................................... 9

- Elytron lacking grooves on dorsal surface or over lateral margin; dorsal surface glabrous or with disperse short, broad, golden, scaly setae ( Figs 23–26 )................................................................................ 13

9. Elytron with one longitudinal groove over lateral margin bearing short, golden, scaly setae ( Figs 20–21 ); inner surface of meso– and metatibiae with short, stout setae..................................................................... 10

- Elytron with three or four longitudinal grooves on dorsal surface bearing short, golden, scaly setae ( Fig. 22 ) or lacking setae; inner surface of meso– and metatibiae with long, finer setae................................................... 12

10. Antennae reaching 3/4 along lateral margin of pronotum; prosternal process produced backwards, surpassing the midpoint of the space between pro– and mesocoxae ( Fig. 14 ); pseudopleuron and epipleuron glabrous, lacking protuberances or punctures; ( Fig. 20 )........................................................................ P. (Praocis) marginata Germain

- Antennae reaching midpoint of lateral margin of pronotum; prosternal process produced backwards, not reaching the midpoint of the space between pro– and mesocoxae ( Fig. 13 ); pseudopleuron with setae arising on punctures; epipleuron with setae arising on protuberances....................................................................................... 11

11. Lateral quarters of pronotum and dorsal surface of elytron glabrous; elytron with one carina more approximate to lateral margin than suture, with a broad groove over lateral margin occupying outer third or quarter of elytra bearing short, golden, scaly setae ( Fig. 21 )............................................................ .. P. (Praocis) elliptica Philippi & Philippi

- Lateral quarters of pronotum and dorsal surface of elytron with short, golden setae; elytron lacking carinae, with a narrow groove over lateral margin occupying only outer sixth of elytra bearing short, golden, scaly setae.... P. (Praocis) subaenea Erichson

12. Elytron with three longitudinal grooves weakly demarcated bearing sparse short, broad, golden, scaly setae, intervals arched ( Flores & Pizarro-Araya 2010, Fig. 1 ); ventral surface of meso– and metafemora lacking a row of setae on posterior edge............................................................................. P. (Praocis) sulcata Eschscholtz

- Elytron with three or four longitudinal grooves well demarcated bearing abundant short, broad, golden, scaly setae, intervals carina–shape ( Fig. 21 ); ventral surface of meso- and metafemora with a row of setae on posterior edge.................. ........................................................................ P. (Praocis) spinolai Gay & Solier 13. Elytral punctures twice the size of pronotal punctures; elytron with a carina more approximate to lateral margin than suture ( Fig. 23 ); ventral surface of meso– and metafemora lacking a row of setae on posterior edge; inner surface of meso– and metatibiae with short, stout setae......................................................... P. (Praocis) medvedevi sp. nov.

- Elytral punctures same size as pronotal punctures; elytron lacking carinae or with two or three weakly defined carinae equidistant between suture and lateral margin ( Figs 24–26 ); ventral surface of meso– and metafemora with a row of setae on posterior edge; inner surface of meso- and metatibiae with long, finer setae....................................... 14

14. Antennae reaching midpoint of lateral margin of pronotum; width of anterior margin of pronotum not exceeding half the width of posterior margin; posterior angles of pronotum acute; elytron lacking carinae..................... P. (Praocis) curta Solier

- Antennae reaching 3/4 along lateral margin of pronotum; width of anterior margin of pronotum exceeding half the width of posterior margin; posterior angles of pronotum right; elytron with two or three weakly defined carinae equidistant between suture and lateral margin.............................................................................. 15

15. Elytron rugose with a net of lateral ramifications from carinae ( Fig. 24 ); metatibiae curved outward............................................................................................... P. (Praocis) aenea Gay & Solier

- Elytron punctured and dorsal surface lacking a net of lateral ramifications from carinae ( Figs 25–26 ); metatibiae straight.. 16

16. Pronotum and elytra with small punctures; elytron with two or three carinae ( Fig. 25 ); lateral styles of tegmen with proximal margin ventrally concave and with abundant setae on distal third of ventral surface; median lobe distally broadened................................................................................... P. (Praocis) tibialis Gay & Solier

- Pronotum and elytra with big punctures; elytron with two carinae ( Fig. 26 ); lateral styles of tegmen with proximal margin “inverted V”-shaped ventrally, and with sparse setae on distal 1/5 of ventral surface; median lobe narrowed in pre-distal quarter and distally broadened........................................................ P. (Praocis) parva Gay & Solier

Figures

FIGURES 1 − 4. Scanning electron micrographs of body details of Praocis (Praocis) species. 1. Praocis (P.) subaenea, head in dorsal view. 2. P. (P.) bicentenario sp. nov., antennomeres 9 – 11 in dorsal view. 3. P. (P.) spinolai, lateral margin of pronotum in dorsal view. 4. P. (P.) spinolai, scaly setae of elytron into a groove.

FIGURES 5 − 14. Male and female genitalia and body details of Praocis (Praocis) species. 5. Fore tibia and tarsus in anterior view of Praocis (P.) sanquinolenta. 6 − 9: Male: 6, 7. P. (P.) rufipes, dorsal and ventral views; 8, 9. P. (P.) elliptica, dorsal and ventral views. Abbreviations: bl, basal lamina of tegmen, ls, lateral styles of tegmen, ml, median lobe. 10. Ovipositor (ventral view), spiculum and internal female reproductive tract of P. (P.) hirtella. Abbreviations: c, coxite, o, oviduct, p, paraproct, s, spermatheca, sag, spermathecal accessory gland, sp, spiculum, v, vagina. 11 – 14. Prosternum and mesosternun, lateral aspect. 11. P. (P.) costata; 12. P. (P.) quadrisulcata; 13. P. (P.) elliptica; 14. P. (P.) marginata. Abbreviations: p, prosternum, m, mesosternum. Scale bars: 1 mm.

FIGURES 15 − 20. Habitus in dorsal view. 15. Praocis (Praocis) costata; 16. P. (P.) sanquinolenta; 17. P. (P.) bicentenario sp. nov., holotype; 18. P. (P.) hirtella; 19. P. (P.) subsulcata; 20. P. (P.) marginata.

FIGURES 21 − 26. Habitus in dorsal view. 21. Praocis (Praocis) elliptica; 22. P. (P.) spinolai; 23. P. (P.) medvedevi sp. nov., holotype; 24. P. (P.) aenea; 25. P. (P.) tibialis; 26. P. (P.) parva.