Ischyomius escalonai Pollock, 2009

Pollock, Darren, 2009, A new species of Ischyomius from Venezuela (Coleoptera, Tenebrionoidea, Pythidae) with a revised key to world species, ZooKeys 6 (6), pp. 69-74 : 70-73

Ischyomius escalonai Pollock , sp. n.

urn:lsid:zoobank.org:act:7DFC5962-B47E-4848-9608-C387CE58049B

( Figs. 1-4 )

Type series. Holotype male, labeled: “ VENEZUELA, Lara, P.N. Yacambú, El Blanquito, 1400 m 26.VI.2005; Hermes Escalona, collector” / “coll. on bird of paradise ( Strelitzia ) dry leaves” / “ HOLOTYPE Ischyomius ♁ escalonai, sp. n. D. A. Pollock 2007 ” . Allotype female, same labels as holotype (with “ ALLOTYPE ” instead of “ HOLOTYPE ” on third label). Two paratypes, one male, one female, with same labels as Holotype (with “ PARATYPE ” instead of “ HOLOTYPE ” on third label). Holotype, allotype and female paratype deposited in Museo del Instituto de Zoología Agrícola “Francisco Fernández Yepez”, UCV, Maracay, Venezuela (Luis J. Joly, curator). Male paratype deposited in collection of author.

Derivation of specific epithet. I am very pleased to name this new species after friend and colleague Hermes Escalona, a fellow specialist on the “salpingid group” of tenebrionoid families, and who also collected all known specimens of this species.

Diagnosis. This new species of Ischyomius may be separated from the rest of the genus by the following combination of characters: posterior pronotal bead indistinct; lateral pronotal bead not attaining anterior bead; color uniformly light to medium brown; abdominal ventrites with short but obvious setation; elytral apices rounded, without spine ( Fig. 3 ) aedeagus relatively short and stout, accessory lobes very short, inserted midlength on the tegmen ( Fig. 4 ); known only from Venezuela.

Description. With generic characteristics of Ischyomius (see Pollock 1998: 246- 250), plus the following: total length (TL) 9.9-11.5 mm; greatest elytral width (GEW) 2.8-3.2 mm; body ( Fig. 1 ) elongate (TL / GEW = 3.5-3.8) color uniformly light to medium brown dorsally, without obvious color contrasts, ventrally, thorax and abdominal ventrites slightly darker than legs and elytral epipleuron; eyes moderately protuberant; antennae relatively long, antennomeres filiform, slightly widened from antennomere 5; male lacking pit on mentum; entire dorsal surface of body with shallow, sparse punctation, without any obvious microsculpture; pronotum wider than long (GPW / PL = 1.19-1.21); posterior pronotal bead indistinct; lateral pronotal carinae distinct, smooth, without tubercles, prolonged anteriorly to, and in contact with, anterior pronotal bead; lateral pronotal margins parallelsided basally, then relatively abruptly widened, greatest width anterior of midlength ( Fig. 2 ); anterolateral angles of pronotum rounded, not angulate; disc of pronotum moderately convex with indistinct posterolateral depressions; elytra convex, slightly flattened dorsally, without distinct setation; outer apical elytral spine absent ( Fig. 3 ); thoracic sterna and abdominal ventrites with distinct, almost isodiametric microsculpture; abdominal ventrites relatively coarsely punctate, with short but evident setation; aedeagus ( Fig. 4 ) stout, apicale slightly shorter than basale; apicale broad, tapered distally; accessory lobes narrow, very short, not extended to end of apicale, inserted about midlength of apicale.

Distribution. The four type specimens were collected from a single locality, in Yacambú National Park, Lara State, in easternmost Venezuela.

Natural history. All four specimens were collected by beating withered leaves of “Bird of Paradise” plants ( Strelitzia sp.) (Hermes Escalona, pers. comm.). Very little is known about any other species of Ischyomius , although they seem to be associated with dead or dying vegetation of Musaceae or Palmae ( Champion 1916; Pollock 1998). Although the genus Strelitzia is native to South Africa, and therefore was introduced to the Venezuelan type locality, the family Strelitziaceae is closely related to Musaceae (which are also introduced), in the “banana and ginger” group of plants ( Kress and Hahn 1997). It seems probable that I. escalonai will be found in association with Musaceae , also.

Discussion. The description of I. escalonai brings the total known species in Ischyomius to eight. The first couplet of Pollock’s (1998) key divided the species into two groups: those that have a distinct, posterior pronotal bead and distinct vestiture on abdominal ventrites and those without posterior bead and lacking ventral abdominal vestiture. Each of the four type specimens of I. escalonai are intermediate between these two groups, i. e. without the pronotal bead, but with short, but distinct ventral abdominal vestiture. Therefore, the original key of Pollock (1998), revised by Pollock (2007) for inclusion of I. hovorei , must be amended, as follows. References to figures for species other than I. escalonai refer to figures in Pollock (1998).

1 Pronotum with distinct bead along entire posterior margin (in most speci-mens).......................................................................................................... 2

1' Pronotum without posterior bead, or present laterally only......................... 4

2(1) Antennomeres filiform; elytral apex with conspicuous, outer spine ( Fig. 1 A-D, F)................................................................................................................ 3

2' Antennomeres short, subserrate; elytral apex without conspicuous, outer spine ( Fig. 1E ) ............................................................. I. bicolor Champion

3(2) Antennomeres 2-10 piceous to black, contrasting in color to antennomeres 1 and 11; lateral margins of pronotum with several long setae; body testa-ceous, with median, longitudinal dark vitta extended from frons to elytral apex ( Fig. 1D )............................................................. I. championi Pollock

3' Antennomeres 1-11 concolorous, rufous; lateral margins of pronotum without long setae; body testaceous to rufous with elytral infuscation, around scutellum and rectangular to diamond-shaped, transverse dark area slightly posterior of elytral midlength ( Fig. 1F ) ..................... I. nevermanni Pollock

4(1') Anterolateral angles of pronotum produced, square to slightly acute ( Fig. 1C )................................................................ I. denticollis Champion

4' Anterolateral angles of pronotum not produced, more or less rounded ....... 5

5(4') Lateral pronotal bead attaining anterior pronotal margin, continuous with anterior bead ( Fig. 4B )................................................................................ 6

5' Lateral pronotal bead not attaining anterior pronotal margin ( Fig. 4D ) ...... 7

6(5) Apex of elytron with distinct outer spine ( Fig. 1A ); abdominal ventrites without obvious setation (setae, if present, hidden within punctation); accessory lobes of aedeagus long, greater than half length of apicale, extended to apex of apicale (Fig. 7D)................................................... I. singularis Chevrolat

6' Apex of elytron smooth, without outer spine ( Fig. 3 ); abdominal ventrites with short but obvious setation; accessory lobes of aedeagus short, distinctly less than half length of apicale, not extended to apex of apicale ( Fig. 4 ) ........ ........................................................................... I. escalonai Pollock , sp. n.

7(5') Body color uniform, from testaceous to rufous ....... I. chevrolati Champion

7' Body color orange-red except for elytral apices, femora and tibiae piceous to nearly black...................................................................... I. hovorei Pollock

Figures

Fig. 1. Dorsal habitus of Ischyomius escalonai sp. n., male paratype. TL = 11 mm.

Fig. 2. Ischyomius escalonai sp. n., male, detail of forebody. Scale bar = 1 mm.

Fig. 3. Ischyomius escalonai sp. n., male, detail of elytral apices. Scale bar = 1 mm.

Fig. 4. Ischyomius escalonai sp. n., aedeagus, dorsal view. Scale bar = 0.5 mm.