MYRIAPODOLOGICA Virginia Museum of Natural History Voi. 8, No 10 ISSN 0163-5395 28 February 2006 Four new psaphodesmine genera from the Papuan Region (Polydesmida: Platyrhacidae) By Richard L. Hofftnan ABSTRACT 7’he nev\ platyrhacid gcnom Acerhacus (type species: A. oxyhmus, n. sp.) and Clastrorhacus (type species: Platvrhacus acmophorus Chamberlin), arc described from New Guinea; Beiarhacus (type species: Piatyrrhacus fallens Chamberlin) from the Solomon Islands, and Corymhorhacus (type sjjecies: C manus, n. sp.) from the Bismarck Islands. Ongoing investigation of the platyrhacid fauna of Indonesia has disclosed botli undescribed species as well as a number of named forms which are no longer referable to Platvrhacus, the genus in which they were described. Some of these orphaned species are accommodated in the new genera proposed here as part of a continuing survey of the tribe Psaphodesmini, initiated with my recent ( 1 997) account of Par azodesmus. Several larger genera such as Ozorhaciis will be discussed in individual accounts as the opportunities arise. TRIBE PSAPHODESMINI Psaphodesmini (as subfamily) Cook, 1896, Brandtia, p. 4. Hoffman, 1980, Classifi- cation of the Diplopoda, p. 163 (as tribe). Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) 94 Myriapodologica Because of the apparently random loss or gain of apical gonopod processes, it is not possible for me to identify- any single apomorphic condition that defines this taxon, nor phrase a definition that is not extensively qualified to account for exceptional conditions. Yet the genera (species groups) appear to be both intcmalh' cohesive and related by characters shared in a variety of combinations. Possibh . greater precision \m 11 result from knowledge of the numerous psaphodesmine t>pes remaining to be discovered throughout Indonesia. Members of the tribe abound in all of the islands from Sulawesi to Guadalcanal without, at least with present infonnation, much correlation of gonopod diversification with geography. In addition to the four proposed herein, the follow mg genera arc referable to the Psaphodesmini: Psaphodesmus Qook, 1896 Zodesmiis Cook, 1 896 Farazodesmus Pocock, 1898 Pleorhacus Attems, 1914 Ozorhacus Attems^ 1933 I'jyfhrhacus Hoffman, 1962 Petaiorhacus 1997 Corymhorhacus. new genus Type species: C. maims, new^ species. Name: A neologism composed of the Greek elements korymhos {group.clustcr) and rhaciis (from the generic name Platyrhacus)^ in reference to the crowded basal placement of the five apical tclopodite processes. Diagnosis: Gonotclopodite with five distal elements, the fomiula a,b,c.D,E; D and E nearly svTitopic, generally similar in size and shape, notably divergent: processes a, b, and c distinct and separate, not borne at the end of a common basal stem and much shorter than processes D and E. Coxal setae moderate in size, slightly peniciliate apically. Remarks: Corymborhacus shares the full compliment of five apical processes with only two other genera: Psaphodesmus and Parazodesnms. In both of these taxa. processes a. b, and c are located distally on a long slender stem, and the gonocoxa is provided with a dorsal field of long, robust, apically peniciliate setae. Process e is greatly reduced in Psaphodesmus, and the entire femoral region of the tclopodite is very slender and sinuous in Parazodesnms. The absence of a long common stalk cany ing the three distal processes is possible' a more generalized condition, although the isolated, peripheral location of the t>pe species might imply a recent denvative state. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) Hoffman; New psapliodesmine genera 95 TTie possibilit\ that this species ma\ have been introduced on Manus from somewhere in New Guinea must be taken into account. Figs. 1-5. Corvwhorhaciix manus, new species. 1. Left side ofcollum, dorsal aspect. 2 Left side of mciaicrgum 9, dorsal aspect. 3. Left side of metatergum 13. dorsal aspect. 4. Co.xal sockets and stigmata of midbody segment, oblique ventro-lateral aspect. 5. Segments 19 and 20. dorsal aspect. All drawings from holoupe. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) 96 Myriapodologico Corvnihorhacus manus, new species Figures 1-8 Name; The name of the island on whicli the species occurs, considered a masculine noun in apposition, and also in allusion to the Latin word matins, as the gonopod as seen in mesal aspect fancifully resembles a hand with five dissimilar fingers, bent at the wnst at a right angle. Mv tERiAL; Male holohpe (ZMC) from: PAPUA NEW GUINEA: Manus Island I Admiralty Islands}: Lorengau: 22 June 1962, "Noona Dan” Expedition. Holoia'PE; Fragmented, approximate length 34 mm, width of col him 3.8 mm. of segment 2, 5.5. of segment 4. 6 2, of segments 5-14 ca. 6.5 rnm: W/L ratio at midbody about 19%. Color of now-faded specimen unifomiK light reddish-brow n, with legs, antennae, paranotal peritremata. and larger dorsal tubercles yellowish. Mead width 3.5 mm at genal apices, surface finely granulate, epicranial suture obscure; lower half ofgenae plane, dorsal half convex; interantcnnal space broad ( 1 .2 mm), one-third head width, and about equal to length of I and 2"^ antennomcres combined: antennae short and stout, reaching back to middle of 2"'‘ paranota. each article except T* and 6^ only slightK' longer than broad. Collum small, only slightly broader than head, lateral ends present oni\ as small lobes with smooth surface; disk almost smooth, tubercles present chieflv' as a senes of 7-7 on posterior margin, the outermost three on each side b> far larger than the more median (Fig. I) Paranota of subsequent body segments abruptK wider than collum. those of segments 2-5 dcclivent. thereafter becoming nearly horizontal and imparting a distinctly "flat-backed" aspect; metaterga set with numerous flat tubercles ofvary -ing size, more prominent on paranota, oni\ a row of 4-4 enlarged tubercles along caudal margin, the outermost ftvo on each side by far the largest (Figs. 2, 3). Anterior and posterior edges of paranota nearly smooth, lateral edge straight on antenor segments, posterior to 5^ becoming indented at midlength, ozopores large and distinct, located at base of posterior paranotal lobe ncarl> in contact with indentation Postenormost segments with traces of anterior and median series of enlarged tubercles. Outline of cpiproct (Fig 5). Paraprocts nearly flat, with notably enlarged basal “condylar lobe ' overlapping lateral end of hypoproct; latter broadly trapezoidal, the basal edge convex, not overlapping on preceding segment. Podostema broad (ca 1.7 mm at midbody), flat, scarcely elevated, without subcoxal spines, glabrous. Sides of metazona granular, without enlarged tubercles. Stigmata with large, elevated and crenulatcd rims, both pairs of near equal size (Fig. 4). Legs short, stout, the femora in particular subincrassate. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) Hoffman: New psaphodesinine genera 97 Gonopod aperture moderate in size, transversely oval, the posterior and especially lateral ends elevated as a high thin rim. Gonopods (Figs. 6-8) as described in the generic heading, and illustrated below Figs 6-8. ('orvmhorhacus manus^ new species. 6. Left gonopod, mesal aspect. Fig. 7. Telopodite ofleft gonopod, lateral aspect. Fig. 8. Telopodite of left gonopod. dorsal aspect. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) 98 Myhapodologica Acerhacus^ ne\\ genus Type spi-cies: A. ox)'!omu.s\ n. sp. The genus also includes FJaWrhacus per- gramdosus Silvestri, 1 895, from Moroka, New Guinea. Diagnosis: Apical process formula of gonotclopodite (a, c) E: process E elongated, extended dorsad in parallel w ith the distal region, latter abruptl\ bent dorsad, terminating in only two processes a and c, the former sinuate at its base. Gonocoxac with large, apically penicillatc setae Name: A neologism composed of the prefix derived from the three gonopod processes a, c, and e, + the Greek stem -rhacus, commonly used in generic names in this family. Remaf^ks: At first glance, it might appear that Platyrhacus papuamis Attems ( 1 9 14) is referable to this genus, but re-exam i nation of the type material revealed that the subterminal gonopod process shown on Attems’ figure 60 is in fact d.. Acerhacus oxylomus, mw species Figures 9-14 Maierial: Male holotypc (Naturhist.Mus.Wien) from I^\PL'A \n\v giixea: Morohe District between Aseki and Haintiba (ca. 70 km west of Wau), 27 Sept 1972, leg.? (J. Eiselt don.). Hol.otype: Adult male, length ca 45 mm (specimen fragmented), widths of selected segments as follows; collum, 5.5 mm; 7.7 mm, 4^^. 8.3, 6th- 12th. 8.5 mm, 16^^, 8.1 mm, 1H‘^ 6.5 mm. Present color (faded in alcohol) light brown (originally maroon?) dorsalK . lateral third of paranota and metatcrgal tubercles clear yellow, anterior and posterior margins of paranota white; legs, antennae, and ventral surfaces yellow ish brown. Head unmodified: cpicranium finely granulate, with deep median groove: face smooth, genal depressions prominent, labrocKpeal offset distinct: 4-4 ch peal setae, 6-6 labral setae (both senes with compound setae). Antennae short, stout: interantennal space equal to length of 2nd antennomere (0.9 mm). Collum (Fig. 9): dorsal surface finely granular, nearly flat, with anteromedian depression; a prominent row of 6-6 enlarged, flattened, coalesced tubercles behind anterior margin; paranota set abruptly lower and slightly declivous, the lateral apices smooth and polished: a transverse series of 5-5 enlarged tubercles preceding posterior edge and several similar but smaller tubercles dispersed over median discal area. Mctatcrga moderately convex, surface coriarious with three transverse rows of tubercles, 4-4 in each, those of rows 1 and 2 smaller, subequal in size, tvpicalh’ round; those of row 3 much larger, more oval, except on postcriormost segments Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) Hoffman: New psaphodcsmine genera 99 Figs. 9-12. Acerhacus oxylomus. new species. 9. Left side of collum and segment 2. dorsal aspect 10 Left paranotum of segment 9, dorsal aspect. 1 1 . Left paranotum of segment 12, dorsal aspect. 12. Right side of epiproct and segments 18 and 19, dorsal aspect. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) 100 Myriapodologica where all tubercles are subequai in size and shape. Paranoia large, set high on sides, only slightly declivous, typically incised into two major lobes, the anterior smaller and becoming more so posteriad (Figs. 10 and 1 1); surface finely granular except the smooth and thickened lateral margins: ozopores large, set near midlength at base of postenor lobe, nearly in contact with lateral edge; posterior edge finch' crenulatc. narrowK^ margined. Postenor segments as in Fig. 12: paranota of segment 19 spinifonn, essentially lacking anterior lobe: epiproct broad, apicalK rounded, not constricted at base Paraprocts and hypoproct of fonn typical for family. Legs attached to low, broad, podostema (width 1 .6 mm at midbody) without trace of subcoxal spination. Legs long and slender, apex of femora visible bc\ond paranota in dorsal aspect, podomeres slender and sparsely set with shoit stout glandular setae. Stigmata unusually large, the rims elevated, similar in size and shape (vertically elongated slits) except anterior more sigmoid and extended ventrad in front of anterior dorsal cond>ie. Gonopods (Figs. 13, 14) as described for the genus, specific characters in the presence of a mdimentary' prefemoral process, the relatively short and acuminate process e, and the sigmoid curv ature of the solcnomerc (a) Acerhacus pergranulosus (Silvcstri), new combination Figure 15 Platyrhacus pergramdosus Silvestri, 1895, Ann. IVliis. Civ. Stor. Natur. Genova, V, 34, p.639, Male holotype (Mus. Hist, Nat Genova) from "Moroka". New Guinea. Material: The male holotype. which I studied in 1975. and illustrated the left gonopod.. Description (translation of the original Latin text): '"Browiiish-rcd. comers of the paranota becoming yellowish. .Antennae short Collum subscmicircular. as w ide as the head, anterior comers strongly produced, entire dorsum ornamented with numerous small granules as well as three rows of large tubercles. Apex of last segment broadly rounded. Paranota (“carinis' ) of remaining segments liorizontal. anterior and posterior comers nearly square, strongly produced around a large incision. Legs invested below with clavate hairs. Male gonopods ending in two processes, the outer of which is apically bipartite. “Length of body. 42 mm. w idth 8 mm. Rj-aiarks: This species is generally very similar to oxylomns^ but quite distinct in tcmis of gonopod stmeture; a much larger and longer process E, and shorter a with basal lobe (Fig. 15). Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) Hoflfman: New psaphodesminc genera 101 Figs. 1 3-14. Acerhaciis oxylomus, new species 1 .3. Left gonopod. mesal aspect. Fig. 14. Left gonopod. dorsolateral aspect. Fig, xlcerhacus peryramiiosus {Si\\es\xi). left gonopod. mesal aspect. Drawings from holohpe specimens. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) 102 Myriapodoiogica Clastrorhacus, new genus T^'FE SPRCfES: Platyrhacus acmophonis Chamberlin. 1945. N.ame; a neologism composed of the two elements kiasterion {Gk. a paining knife) + "^-rhacus ' , a common combining fomi in this family derived from the generic name PlaWrhacus . The name refers to the shape of process c of the tclopodite. Diagnosis: Gonotelopodite process formula a, C: C entarged. falcate, directed dorsomesad. distally recurved. Process a relatively short, slightly sinuous pro.vimad. Coxal setae numerous, large, long, distally pemcillate. Species; Only the type species is referable to this genus. Remarks; Identification of the larger distal process as C is a little provisional, but selected because of its location considerably distad of where one would expect e to occur. Whatever the true homology happens to be, the configuration is unique w ithin the Psaphodesmini and merits generic level recognition Complete suppression of C and corresponding elongation of a would produce a gonopod resembling that occurring in the Phillippine genus liodesmus. Clastrorhacus acmophorus (Chamberlin), new’ combination Figs. 16-19 Platyrhacus acmophorus Chamberlin, 1945. American M us. Nov.. 1282: 16, figs. 69-71. Male holotype and 10 topoparat\pcs (AMNH) from Doonnanpad, ■'New Guinea*’ [now in Irian Ja>a. Indonesia]. Materiai,: Male and female paratxpe (VMNH). Male: Specimen broken, length approximately 50 mm. Width of collum. 4.5 mm. 2""^ segment, 8. 1 mm; 4^^, 9.2mm: 6*^ 9.7mm: 10^^ 9.8 mni. 14^^, 9.6mm: I6‘*^, 7.4 mm; 18^*k 7 0mm. LAV ratio near 20%. Onginal color lost from long preservation, but apparently dark brown or black dorsal iy, with paraiiota, tergal tubercles, legs, and antennae yellow . Head and antennae of typical formation; front of head microgranulate. labmm glabrous; genal groove verv' shallow : epicranial groove deeply impressed between antennae Metaterga glabrous, smooth and polished, no trace of arcation or transverse sulcus, with three transverse series of rounded tubercles, largest on anterior segments, gradually reduced posteriad, first series more distant from 2""^ and number of tubercles varying randomly from 3-3 to 5-5 on different segments. Paranoia set high on sides, nearly horizontal, vers deeply incised (Figs. 16-17), ozopores placed near end of incisions; anterior and posterior edges omamented with Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) Hofiftnan; New psaphodesmine genera 103 « C 16 G G c Figs. 16-19, ilasirorhacits acmophorifs {Chnn'ibQTVin) Fig 16. Left paranotum of segment 9. dorsal aspect. Fig, 17. Left side of paranoia IX and 19 and epiproci. dorsal aspect. Fig. 18. Left gonopod. mesa! aspect. Fig. 19. Telopodite of left gonopod. dorsolateral aspect. Drawings from paratype. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) 104 Myriapodologica a single row of close-set rounded tubercles, creating a somewhat crenulatcd appearance. Posterior end of body of typical plat\'rliacid fonn (Fig. 17) Sides of metaterga with sparse, dispersed rounded tubercles, no marginal series, only a few enlarged tubercles above base of posterior legs Sterna of antenor legs narrow^ and deeply bicniciatel> impressed, coxae separated by a distance less than a coxal length, veiy small subcoxal cones present back to first legs of S'*’ segment, thereafter sterna somewhat broader, strongly elevated, glabrous, about as wide as length of prefemora. Gonopod aperture small, rounded, lateral and posterior edges strongly elevated and thickened Gonopods as described under generic heading and shown by Figures 18 and 19. Fragmented, length about 56 mm. maximum widtli at midbody 1 1.0 mm, LAV ratio near 20%. Peripheral characters ver\ similar to those of male, but dorsum somewhat more convex and tubercles distinctly larger lietarhacuSf new genus TvPLsrEcuis; Platyrrhacus fallens Chamberlin. 1920. Name: A neologism composed of the elements beta (the Greek letter “b'O + the combining suffix -rhacus, m reference to the unusually large distal process b of the gonotclopodite. Diagnosis: A disjunct psaphodesmine taxon with gonopod fonnula (a+ B) D, E, process B nearly twice as long as a, attenuated, curved ventromesad; processes D and E syntopic, D straight and spiniform, E slightly sinuous, directed proximad Rem-aj^ks: The affmities of this species ma\' be sought in the sympatric genus Parazodesmus, represented by several species in the Solomon Islands (Hoffman. 1 997), two of which {schisiogon gonethus Chamberlin) are generalh similar in gonopod form to other species in New Britain. The third {verrucosus Pocock) is somewhat more like R. fallens in having a distinctly shorter telopoditc, with the distal processes arising near the priman curvature. Although annectent species ma>' be discovered in the Solomons, I believe that Bctarhacus may be justified by the combined traits of; process c entirely suppressed; processes D and E syntopic at their base instead of widely separated as typical of Parazodesmus: and absence of long pcnicillate coxal setae. I provide (Fig. 22) a drawing of gonopod stnicture in verrucosus for comparison with that of fallens to show these differences. The general impression is that the gonopod of fallens is a notabh condensed derivation of the tvpical Parazodesmus version, perhaps the result of divergence at the eastern periphery of the range of that genus. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) Hoffman: New psaphodcsminc genera 105 Figs. 20-21. Betarhaciis fallens (Chamberlin), Fig. 20. Left gonopod. mesal aspect. Fig. 21. Tclopodite of left gonopopd. dorsolateral aspect. Fig. 22. Parazodesmus verrucosus (Pocock). lelopodtieof left gonopod. dorsolateral aspect, to compare with Fig. 21 . Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) 106 Myriapodologica In 1967 I examined the hoIoUpe of failem and prepared two drawings of the gonopod structure, but time did not pennit making a fuller description of body form Betarhacus fallens (Chamberlin), new combination Figures 20-21 Platyrrhacus fallens Chamberlin, 1920, Bull. Mus. Comp. Zool., 54: 142. Male holotype (MCZ 4985) from Fulakora, Solomon Islands. Description (abstracted from Chamberlin 1920): Metazonites dark brown; prozonites with brown in a spot on middorsal region, on each side and ventrally. the intervening portions yellow; borders of paranota fulvous. Surface of head strongly granulotubercular except for the smooth labrum Metaterga with three rows of distinct, rounded, w idelv' separated tubercles. Ozoporcs veiy large, located about one pore radius from lateral paranotal edge, latter tvpically with three dentations between the comers, occasionally as many as four or five. Gonopod (from personal examination) as shown in Figures 20 and 21 . Coxae with only a few' short, apicalK' tmneate setae on dorsal surface Tclopodite relatively short beyond trhe primary cur\^ature. at which level processes D and E originate, continued as an evenly attenuated arc (b) directed ventromesad across mesal side of telopodite. Process a much smaller, largely concealed behind b m mesal aspect and entirely so in dorsal aspect. No trace of process c. ACKNOWLEDGEMENTS 1 am pleased to express my^ thanks to Prof. Dr. Henrik Enghoff, Natural History' Museum of Denmark, Kobenha\n (ZMC), Dr. Jurgen Gruber, Naturhistorisches Museum. Wien (NMW)), and Dr. Herbert W. Levi, Museum of Comparative Zoology, Cambridge (MCZ) for access to material under their care. REFERENCES Chamberlin, R. V. 1920. The Myriapoda of the Australian Region. Bull.Mus. Comp. Zook, 54: 1-269. Chamberlin, R. V. 1945. On some diplopods from the Indoaustralian Archipelago. American Mus. Novitates, 1262: 1- Cook, O. F. 1897. A synopsis of Malayan Platyrhacidae. Brandtia 1:1-4. Hoffrnan, R. L. 1980. Classification of the Diplopoda. Geneve, Museum d'Histoire Naturclle. 236 pages. Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org) Hoffinan: New psaphodesmine genera 107 Hofftnan. R. L, 1997, Synopsis of the milliped genus (Polydesmida: Platyrhacidac) Steenstrupia (Zool. Mus. CopenJiagcn). 23; 21-36. Silvestri, F. 1 893. Chilopodi e Diplopodi della Papiiasia Ann, Mus, civ. Stor. nat. Geno\'a, Address of the author: Dr. Richard L. tioffnian Virginia IVIuscum of Natural Histoiy Martinsville, Virginia 241 12, USA Scanned with permission by the Virginia Tech Insect Systematics Group 2014 (www.jointedlegs.org)