ANNALS OF CARNEGIE MUSEUM VoL. 67, Number 3, Pp. 245-264 13 August 1998 REVISION OF THE NEOTROPICAL GENUS ISCHYOMIUS WITH A DISCUSSION ON ITS SYSTEMATIC POSITION (INSECTA: COLEOPTERA: TENEBRIONOIDEA: PYTHIDAE) Darren A. Pollock’ Rea Postdoctoral Fellow, Section ofInvertebrate Zoology Abstract The Neotropical genus Ischyomius Chevrolat is reviewed and comprises six species: I. singularis Chevrolat, L denticollis Champion, /. chevroiati Champion, I. bicolorChampion, I. nevermanni, new species (Costa Rica, Limon Province), and /. championi, new species (Ecuador, Pichiocha Province). The following new synonymies are proposed: Pseudoischyomius Pic 1923 = Ischyomius Chevrolat 1878; Pseudoischyomius rufipennis Pic 1923 = Ischyomius bicolor Champion 1916. Primary types were examined for all species, and lectotypes are designated for /. singularis and 1. chevroiati. The systematic placement ofIschyomius is discussed, and based on structure ofmale and femalegenitalia, the genus is placed in the family Pythidae, provisionally near Sphalma Horn. Key Words: insects, Coleoptera, Tenebrionoidea, Pythidae (Ischyomius), Neotropics Introduction The Neotropical genus Ischyomius Chevrolat, like other enigmatic taxa within Tenebrionoidea, never has had a stable family placement. The genus was de- scribed by Chevrolat (1878) in Tenebrionidae, Acropteron Perty. Champion (1886) lelained this position, and created the ‘Tschyomiides,” stating that many features of Ischyomius differed significantly from Acropteron and other tenebri- onids. Later, Champion (1889) transferred Ischyomius to Melandryidae, based on possession ofopen procoxal cavities. This new placement was reflected in Cham- pion’s (1916) treatment of Melandryidae, in which Ischyomius is placed in the Ischyomiina, after the genus Synchroa Newman. Beginning with Csiki (1924), Ischyomius was placed in the Tetratominae (Melandryidae), near Synchroa. This was followed by Blackwelder (1945), Crowson (1955) as Tetratomidae, and Ar- nett (1983). Lawrence (1982) placed the genus in Pythidae without explanation, but stated that it was a very distinct group. Watt (1987) moved Ischyomius into Trictenotomidae based on adult similarities exhibited between the two taxa. Pol- lock (1994) stated, in the absence of detailed analyses, that Ischyomius belonged in Pythidae, based on structural similarities in male and female genitalia. This hypothesis was adopted by Pollock and Lawrence (1995). Lawrence and Newton (1995) treated the genus as Pythidae, incertae sedis. This paper presents a taxonomic revision of Ischyomius, in which evidence is presented for the placement of the genus in Pythidae, provisionally near Sphalma Horn. ' Current address: Department ofEntomology, University ofManitoba, Winnipeg MB R3T 2N2, Can- ada. pollockd@cc,umanitoba.ca Submitted 22 July 1996. 245 246 Annals of Carnegie Museum VOL. 67 Materials and Methods Collection abbreviations used in the text .are: AAAC, AlbertA. Allen collection, Boise, Idaho; BMNH, The Natural History Museum, London, United Kingdom; CASC, California Academy of Sciences, San Francisco, California; CMNH, Car- negie Museum of Natural History, Pittsburgh, Pennsylvania; CNC, Canadian Na- tional Collection of Insects, Ottawa, Ontario, Canada; DAPC, Darren A. Pollock private collection, Carnegie Museum ofNatural History, Pittsburgh, Pennsylvania; FMNH, Field Museum of Natural History, Chicago, Illinois; FSCA, Florida State Collection of Arthropods, Gainesville, Florida; INBC, Instituto Nacional de Bio- diversidad (INBio), Heredia, Costa Rica; MNHN, Entomologie, MuseumNational d’Histoire Naturelle, Paris, France; MUCR, Museo de Insectos, Universidad de Costa Rica, Ciudad Universitaria, Costa Rica; NMNH, National Museum ofNat- ural History, Smithsonian Institution, Washington, D. C.; OXUM, Hope Ento- mological Collections, Oxford University Museum, Oxford, United Kngdom; RHTC, Robert H. Turnbow, Jr. Collection, Fort Rucker, Alabama; SEMC, Snow Museum, University of Kansas, Lawrence, Kansas; SMTD, Staatliches Museum fur Tierkunde, Dresden, Germany. The techniques used for specimen preparation and study are the same as those explained in Pollock (1995). Type specimens were examined for all species of Ischyomius; label data are enclosed in quotes and individual labels are separated HL— by a slash (/). Measurements are presented in millimeters, as follows: length of hea—d between anterior margin of labrum and ant—erior margin of pronotum; GHW- -maximum width around head, across eyes; PL —length ofpronotum along midline; GPW—“-maximum width across pronotum; EL length of elytron from humerus to apex of spine; GEW—^maximum width across both elytra; TL-^-sum of HL and PL and EL. Taxonomic Accounts Genus Ischyomius Chevrolat, 1878 Ischyomius Chevrolat, 1878:98; Champion, 1886:258; Champion, 1893:548; Champion, 1916:81; Seidlitz, 1916:387; Seidlitz, 1917:88 (as Ischiomius); Csiki, 1924:6; Blackwelder, 1945:494; Crowson, 1955:113, 132; Lawrence, 1982:544; Arnett, 1983:2; Watt, 1987:115; Pollock, 1994: 522; Pollock and Lawrence, 1995:466, 468; Lawrence and Newton, 1995:897. Type species, Ischyomius singularis Chevrolat, by monotypy. Pseudoischyomius Pic, 1923:21; Blackwelder, 1945:494. Type species, Pseudoischyomius rufipennis Pic, by monotypy. New synonymy. Dfflgwoj'A.“—Specimens of Ischyomius may be distinguished from other genera of Pythidae based on the following character states (also see key in Pollock and Lawrence [1995]): mandibles with lateral flange (Fig. 2A, D); pronotum wide, at least indistinctly expianate laterally, with distinct lateral carina; tarsomeres 1-4 (1-3 on hind legs) lobed (Fig. 3D), densely setose ventrally; elytra widest ante- riorly, distinctly tapered posteriorly (Fig. 1). — antDeersicorrliyptainodn.narBroodwyed(Fpiogs.te1r)ioerlloy;ngTatLe5(.T9-L1/3G.4E;WG3E.5W“4.13.)5,-3f.l8a.ttened slightly dorsoveetrally, widest Head relatively short and wide, narrowed behind eyes; eyes large, relatively coarselyfaceted, emar- ginate slightly near antenna! insertions; frontoclypeal suture indicated laterally, medially marked by transversely sunken area; labrum transverse, anteriormargin slightly emarginate to truncate; antennae elongate, antennomeres subserrate to filiform, slightly to moderately flattened. Mandibles (Fig. 2, 3B) large, prominent, slightly asymmetrical; apices unidentate, with small ventral accessory tooth situated posterior of apex; ventral lateral flange distinct, extended from accessory tooth to basal point of articulation; terebra! teeth (Fig. 2E:t) short, blunt; both mandibles with dorsal carina (Fig. 2D:dc), — 1998 Pollock Revision of Ischyomius 247 — Fig. 1. Dorsal habitus ofIschyomius species. A, /. singularis Chevrolat (TL 11.7 mm); B, I. chev- rolati Champion (TL 9.9 mm); C, /. denticollis Champion (TL 10.1 mm); D, I. championi, n. sp. (TL 9.5 mm); E, /. bicolor Champion (TL 10.6 mm); F, I. nevermanni, n. sp. (TL 8.7 mm). significantly more distinct on right mandible; ventral microtrichia (Fig. 2B:mi) elongate, extended posteriorly onto distinct prostheca (Fig. 2F:p); mola (Fig. 2C:m; 3B) distinct, subtriangular, concave and convex on left and right mandible, respectively; occlusal surface of mola composed of rows of minute asperities. Maxilla with large, subtriangular galea, fringed with dense, fine setae; lacinia re- duced in size, fringed apically with long setae; apical maxillary palpomere securiform (Fig. 3A). Mentum (Fig. 3A) distinctly transverse, anterior margin evenly arcuate or slightly lobed; distinct pit 248 Annals of Carnegie Museum VOL. 67 — Fig. 2. Mandibles ofadult Ischyomius chevrolati. A, left mandible, dorsal; B, left mandible, ventral; C, left mandible, occlusal; D, right mandible, dorsal; E, right mandible, ventral; F, right mandible, occlusal, dc = dorsal carina, m = mola, mi = microtrichia, n = basal notch, p = prostheca, t = terebral tooth. Scale bar = 0.1 mm. (Fig. 3A:p) in mentum in males of two species. Labium with apical palpomere similar in shape to maxillary palp, slightly securiform (Fig. 3A). Prothorax widerthan long, widest anteriorly; pronotal disc slightly and more or less evenly convex, with small depressions posterolaterally; disc slightly explanate laterally in one species (/. singularis); lateral edge ofpronotal disc smooth (Fig. 4C) orwith small tubercles (Fig. 4A); lateralpronotalcarina distinct along entire lateral margin; posterior pronotal margin with or without distinct bead, at least vaguely bisinuate; prosternum anterior of coxae distinct; prosternal process (Fig. 3C) distinctly pro- duced posteriorly between coxae; apex ofprocess broadly rounded and margined; procoxae rounded, not extending significantly below process; procoxal cavities open externally and internally; protro- chantins concealed. Elytra elongate (Fig. 1), about 2.3-2.8 times longer than wide; sides subparallel anteriorly, then narrowed posteriorly; lateral margins visible dorsally or narrowly concealed; humeri distinct; disc evenly convex; epipleuron distinct, wide anteriorly, narrowed posteriorly, traceable to, orjust anterior of, apical spine; apex ofelytra with variously acute spine, indistinct in one species; scutellum trans- verse, broadly rounded posteriorly; mesosternum narrowly separating mesepisterna, sloping from an- terior margin to intercoxal process; mesocoxae separated narrowly, trochantin concealed or barely visible between lateral extensions of meso- and metasternum; mesocoxal cavities closed partly by mesepimeron; metasternum convex, without distinct median line; metendosternite (Fig. 6) with mod- — 1998 Pollock Revision of Ischyomius 249 — Fig. 3. Structural features of adult Ischyomius spp. A, I. singularis, head, ventral view; B, I. chev- rolati, detail of right mandibular mola; C, I. chevrolati, prothorax, ventral view; D, L singularis, foretarsus, dorsal view, p = mental pit. Scale bar = 0.5 mm (A), 0,05 mm (B), 0.4 mm (C), 0.2 mm (D). eratelylong,broadstalk; anteriortendons insertedonelongatearmsdistalofmidlength; laminaebroad, rounded laterally. Hind wing (Fig. 5) with relatively short membrane; veins indistinctly pigmented (shown dark in figure for clarity); area beyond radial cell about 0.3 times as long as entire wing; radial cell distinct, small; medial region with four terminal veins; wedge cell narrow, elongate. Legs slender, femora expanded slightly toward midlength; tibiae very slightly widened apically; apex of tibiae with row of stout setae; tibial spurs short, stout; inner apical surface of tibia with moderately dense brash of setae, especially distinct on fore tibiae; all but last tarsomere expanded laterally, triangular; tarsomeres (Fig. 3D) distally slightly emarginate, ventral surfacewithdensesetae; apical tarsomere narrow, relatively elongate; tarsal claws relatively long and slender. Abdomen with all segments freely articulated; ventral surfaces more or less uniformly punctate, with orwithoutsetae; tergite 8broadlyrounded apically; tergite 8 shallowly,broadlyroundedapically; sternite 8 shallowly emarginate; sternite 9 in males with elongate spiculum gastrale. Aedeagus (Fig. 7, 8B) with tegmen oriented dorsad of median lobe; basaie subequal in length to apicale, or with apicale distinctly longer than basaie; apicale variously narrowed to near apex, cleft slightly; accessory lobes short and angular, to slender and elongate, rounded or slightly spatulate distally, with setaebasally and apically; parameral strutspresent, membranoustowards, andarticulated with, base of median lobe; median lobe paralleLsided, slender, apex evenly tapered, distinctly scler- otized along lateral margins only; tegmenite distinct, subquadrate, adpressed tightly against basaie. 250 Annals of Carnegie Museum VOL. 67 — Fig. 4. Prothoraces ofIschyomius spp. A, /. singiilaris, pronotal disc, anterolateral oblique view; B, /c.hesvirnoglualtair,is,proptrhootrhaoxr,ax,antaenrtieorriovriveiw.ew;ScCa,le/.bacrhev=ro0l.a1ti,mmpro(nAo,taCl),di0sc.,2amntmero(lBa,teDr)a.l oblique view; D, I. Ovipositor (Fig. 8A) elongate, flexible; coxites three-segmented, apical segment distinctly longerthan basal two; coxites sparsely setose, more so distally; two pairs of elongate baculi distinct; spiculum ventrale elongate, subequal or slightly greater in length than ovipositor; styli spindle-shaped. Internal reproductive tract (Fig. 8A) with two-chambered bursa copulatrix (Fig. 8A:b), distal chamber cleft slightly, possibly forming spermatheca (Fig. 8A:s); slender, elongate spermathecal gland (Fig. 8A:g) attached by narrow duct to distal chamber (= spermatheca). — Natural History. Little has been published on the biology or habits of species ofIschyomius. Champion (1916) stated that specimens of1. chevrolati were com- mon in dead banana leaves in Panama. The information below was derived from the label data of specimens examined. Specimens of /. chevrolati were collected from wilted foliage of several species of Musaceae: Musa sapientum L. (banana), M. paradisiaca L. (plantain), and M. textilis Nee. This species was found among banana debris at several quarantine interception points in the USA. Most of the individuals of /. singularis were collected by beating dry banana leaves on a plantation. Specimens of /. nevermanni, new species, were taken from foliage of two genera of Palmae: Cryosophila (= Acanthorrhiza) warscewiczii (H. Wendl.) — 1998 Pollock Revision of Ischyomius 251 r — Fig. 5. Flight wing of/. singularis. Scale bar = 2 mm. Bartlett and Iriartea sp. A specimen of Ischyomius bicolor was collected in a fallen palm (Or—bigna phalerata Martins) frond in Brazil. Distribution. -The species of Ischyomius exhibit a Neotropical distribution, with a range that extends from Costa Rica, through Panama, into northwestern South America as far south as central Brazil (the latter based on one potentially dubious record). Key to Species of Ischyomius Chevrolat 1. Pronotum withdistinctbead along entireposteriormargin (inmostspecimens);abdominal ventrites 1-4 with obvious vestiture 2 1'. Pronotum without posteriorbead, or present laterally only; abdominal ventrites 1-4 with- out obvious vestiture 4 2 (1). Antennomeres filiform; elytral apex with conspicuous, outer spine (Fig. lA-D, F) .... 3 2'. Antennomeres short, subserrate; elytral apex without conspicuous, outer spine (Fig. IE) ... Ischyomius 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 testaceous, with median, lon- gitudinal dark vitta extended from frons to elytral apex (Fig. ID) Ischyomius championi, n. sp. 3'. Antennomeres 1-11 concoiorous, rufous; lateral margins ofpronotum without long setae; body testaceous to rufous with elytral infuscation, around scutellum and rectangular to diamond-shaped, transverse dark area slightly posterior ofelytral midlength (Fig. IF) .... Ischyomius nevermanni, n. sp. 4 (!'). Anterolateral angles of pronotum produced, square to slightly acute (Fig. 1C) Ischyomius denticollis Champion 4'. Anterolateral angles of pronotum not produced, more or less rounded 5 5 (4'). Lateral margins of pronotal disc evenly arcuate (Fig. 4C); lateral pronotal bead not at- taining anterior pronotal margin (Fig. 4D); lateral margins evenly convex to edge ...... .......................................... Ischyomius chevrolati Champion 5'. Lateralmarginsofpronotaldiscstraighter(Fig4A);lateralpronotalbeadattaininganterior pronotal margin (Fig. 4B); lateral margins explanate, flat to slightly concave to lateral edge Ischyomius singularis Chevrolat . . — 252 Annals of Carnegie Museum VOL. 67 — Fig. 6. Metendosternite of/. singularis. Scale bar = 0.5 mm. Ischyomius singularis Chevrolat (Fig. lA; 3A, D; 4A, B; 5; 6; 7D; 10) Ischyomiussingularis Chevrolat, 1878:98; Champion, 1916:81; Csiki, 1924:6; Blackwelder, 1945:494. — Type Specimens. Lectotype, here designated, female, labelled: “[green label with illegible handwritten locality] / Museum Paris 1906 Coll. L. FAIRMAIRE / [red label] TYPE / [handwritten] Ischyomius singularis Chev Bogota”, (MNHN, coll. Fairmaire). Paralectotype male, labelled: “[green label] N Grenad Honda Goudon / Museum Paris 1906 Coll. L. FAIRMAIRE / [red label] TYPE” (MNHN, coll. Fairmaire). OXUM Taxonomic Notes.—Owq specimen from bears the label “Amphora complanata de Breme.” This specimen was mentioned by Champion (1916) as BMNH having been given to the in 1871 as part of the Bowring Collection. Although the label on this specimen predates Chevrolat’s description, Champion states that Amphora complanata is a manuscript name only and he does not question the validity of /. singularis. Amphora is already twice pre-occupied in zoology, once for an echinoderm and once for a weevil (Neave, 1939). Another BMNH specimen in has the label “Amphora sec. Doue’s coll.” I have beenunable to find a citat—ion forA. complanata, and it is here discarded as an available name. Diagnosis. Ischyomius singularis is one of the three unicolorous species in the genus. Its diagnostic features include the mental pit in the male (Fig. 3A) and carinate lateral pronotal margin (Fig. 4A, B). Ischyomius singularis is structurally similar to 1 denticollis, but lacks the produced anterolateral pronotal angles of . the latter. Pronotal features separating 1. singularis and /. chevrolati are given in the key. Description. TL 6.9-13.4; GEW 1.8-3.5. Color uniformly rufotestaceous to rufopiceous. Eyes relatively small, nonprotuberant; antennae relatively long, antennomeres 5-10 filiform, elongate; male — — 1998 Pollock Revision of Ischyomius 253 — Fig. 7. Aedeagi of Ischyomius spp., median lobe removed, dorsal. A, /. bicolor, B, /. nevermanni, oS.caslpe.;bCa,r/=. c0h.e5vrmolmaii(;AD-,D)/,,s0i.n8gumiamris(;E)E., /. denticoliis. a = apicale, al == accessory lobe, b = basale. with pit on mentum; dorsal punctation relatively coarse, sparse, shallow. Pronotum wider than long (GPW/PL 1.2--L4),withoutelongate, erectsetae;posteriorbeadabsent; lateralmarginofdiscvariously crenulate, or tubercuiate, widest anterior of midlength; anterolateral angles rounded; disc relatively flat, slightlyexplanatetolateralmargins, withdistinctposterolateraldepressions; lateralcarinadistinct, present to anterior margin; punctation relatively shallow, irregular. Elytra without regular, erect setae; apical spine very long; punctation fine, shallow. Tarsomeres (all but distal) greatly expanded. Venter of abdomen without distinct vestiture. Aedeagus relatively stout, with apicale subequal in length to basale; apicale broad, almost parallehsided; accessory lobes relatively elongate, inserted proximad to apicale midlength. — Other Material Examined. BOLIVIA. Country record only, (SMTD, 1). COLOMBIA. Magda- lena: San Sebastian de Rabago, Sierra Nevada de Santa Marta, 2000 m, 1l-14Jv.l968, B. Malkin, beating dry banana leaves on plantation, (FMNH, 43); same locality, except 12-13.iv.1968, ex dry banana leaves on banana plantation, (FMNH, 28). Valle: nr. Pichinde, 50002 i8.vii.l970, H. & A. Howden, (CNC, 1). Country records only, (OXUM, 1), (BMNH, 2). ECUADOR. Bolivar: Balzapam^ ba, 1500 m, (MNHN, 3). Chimborazo: Chimbo [= Puente de Chimbo], M. deMathan, 1891, (MNHN, 2). Napo: Lago Agrio (41 Kms. W.), 18,v.1975, Spangler et ah, Ecuador-Peace Corps-Smithsoniae Institution Aquatic Insect Survey, (NMNH, 1); Limoncocha, 250 m, 9-16.iii.1976, J. M. Campbell, (CNC, 2). Pastaza: Cusuimi, Rio Cusuimi, 150 km SE Puyo, 300 m, 15-3l.v.1971, B. Malkin, (FMNH, 2); same data, except 300 m, 18-23.vii.1971, (FMNH, 1); 8 km NE Puyo, 28.iv.1978, C. W. & L. B. O’Brien & Marshall, (FSCA, 1). Pichincha: 47 km SE Sto. Domingo, Rio Paienqiie Sta., 300' m, 22-28.ii.1976, J. M. Campbell, (CNC, 1). PERU. Hudnuco: Yurac, 67 mi E. of Tingo Maria, lLxii.1954, E. L Schlinger & E. S. Ross, (CASC, 1). Lima: Callanga, (FMNH, 8), (NMNH, 2). General locality (not mapped). Nova Grenada, (BMNH, 1). Geographical Distribution.—All examined specimens ofL singuiaris were col- lected in northwestern South America (Fig. 10). Ischyomius chevrolati Champion (Fig. IB; 2; 3B, C; 4C, D; 7C; 8; 11) Ischyomius chevrolati Champion, 1916:82; Csiki, 1924:6; Blackwelder, 1945:494. Type Specimens. ^Lectotype, male, here designated, left specimen on card with two specimens, labelled: “V. de Chiriqui, 25-4000 ft. Champion, / [round label 254 Annals of Carnegie Museum VOL. 67 A B — Fig. 8. A, ovipositor and reproductive tract of female I. chevrolati\ B, aedeagus of /. chevrolati, ventral, b = bursa copulatrix, g = spermathecal gland, m = median lobe, o = oviduct, ps = parameral strut, s = spermatheca. Scale bar = 0.5 mm. with red margin] Type H. T. / [male and female biological symbols] / Ischyomius chevrolati, Ch / B.C.A. Col. IV. 2. Ischyomius singularis Chev. Champ. / [round label with blue margin] SYNTYPE” (BMNH). Paralectotype, female, mounted on same card as lectotype. Two paralectotypes, mounted on one card, one female, the other sex indeterminate, labelled: “V. de Chiriqui, 25-4000 ft. Champion. / B.C.A. Col. IV. 1. Ischyomius singularis Chev. Champ. / Ischyomius singularis Chevr. / [round label with blue margin] SYNTYPE” (BMNH). Ischyomius singularis Champion (not Chevrolat) 1886:259, pi. 11, fig. 17 and 17 a, b, c. — Diagnosis.- Ischyomius chevrolati is recognized by the following features: body unicolorous; males without mental pit; pronotum with lateral margin smooth, Carina dorsal (Fig. 4C, D). Among the other unicolorous species of Ischyomius, L chevrolati lacks the produced anterolateral pronotal angles of/. denticollis (Fig. 1C) and has a different pronotal structure than /. singularis (Fig. 4A, B). — Description. TL 7.7-11.4; GEW 2.2-3.2. Color uniformly rufotestaceous. Eyes relatively small, nonprotuberant; antennae long, antennomeres filiform, relatively elongate; male without pit on men- tum; punctation relatively coarse, more or less uniformly spaced. Pronotum wider than long (GPW/