1994. The Journal of Arachnology 22:131–13 7 REDESCRIPTION AND THE SYSTEMATIC POSITIO N OF THE BRAZILIAN GENUS XENOCHERNES FEIO (PSEUDOSCORPIONIDA: CHERNETIDAE ) Mark S. Harvey: Western Australian Museum, Francis Street, Perth, Wester n Australia 6000, Australia . ABSTRACT. The sole representative of Xenochernes Feio, X. caxinguba Feio from Minas Gerais, Brazil, i s redescribed from a small portion of the type series, and compared with the myrmecophilous genera Myrmochernes Tullgren (South Africa) and Marachernes Harvey (southern Australia) . A strong relationship based upon thre e synapomorphies was found to exist between Myrmochernes and Xenochernes, with an apparent weaker rela - tionship with Marachernes . Myrmochernes and Xenochernes are placed in the Myrmochernetini, new status , within the Chernetinae. The chernetid fauna of South America is di- Xenochernetinae Feio 1945 : 36–37, new synonymy . verse, with some 35 genera occurring south of Xenochernetini Feio : Beier 1970: 51 . the Panamanian isthmus (Harvey 1991) . Of these genera, one of the most peculiar is Xenochernes Diagnosis.—Cheliceral setae sbs and bs strong- Feio, known only from a single Brazilian species , ly clavate ; cheliceral setae is and is nearly con- tiguous; three flagellar blades X. caxinguba Feio. Indeed Feio (1945) consid- ; chelal hand no t ered it so unusual that he raised the monotypic much wider than pedicel. chernetid subfamily Xenochernetinae for its in- Remarks.—The suprageneric relationships of clusion. Feio (1945) also noted similarities with chernetids has long proved taxing . Muchmor e Myrmochernes Tullgren, then placed in the (1972, 1974) has shown that the limits of `classic ' monotypic family Myrmochernetidae, and Ster- family-group names such as Lamprochernetinae , nophoridae . Given that Myrmochernes is now Chernetinae, Chernetini and Hesperochernetin i placed within the Chernetidae (Judson 1985), an d (Beier 1932) are in fact poorly defined entities . the Sternophoridae are considered the sister- Legg (1987) and Legg & Jones (1988) have fur- group of the Cheliferoidea (Harvey 1992b), the ther compounded the problem by defining the taxonomic position of Xenochernes deserves re- Chernetinae and Lamprochernetinae solely base d examination . upon western European species, apparently with - Through the courtesy of Dr. Norman Platnick, out reference to the numerous genera which oc- I have been able to examine four slides of typ e cur outside of the Palaearctic region, or with ref- erence to two other available subfamily names , material of X. caxinguba lodged in Museu Na- cional, Rio de Janeiro (MNR), and am now abl e Goniochernetinae Beier 1932, and Xenocher- to present a redescription, highlighting charac- netinae Feio 1945 . Muchmore (1982) eloquently ters overlooked in the original description . In noted that "The arrangement of these genera into addition, the opportunity is taken to present il- subfamilies and tribes is in a state of flux ." Har- lustrations of selected features of M. africanus vey (in press) discussed these problems in further Tullgren from a female in the American Museu m detail and assigned seven genera to the Lam- of Natural History, New York (AMNH), also prochernetinae and three genera to the Gonioch- examined through the kindness of Dr . Platnick. ernetinae. The remaining 100 or so chernetid Terminology largely follows Chamberlin (1931 ) genera, including those discussed in this paper, and Harvey (1992b) . The number of carapacal were provisionally referred to the Chernetinae , even though this is clearly a group not base d setae follows Judson (1985) : total setae (ocular: median: posterior). upon any apomorphic character states. The two genera considered here are placed in Tribe Myrmochernetini Chamberlin, new status the tribe Myrmochernetini, which is proposed a s Myrmochernetidae Chamberlin 1931 : 240–241; see full a monophyletic group supported by several syn- synonymy under Chernetidae in Harvey 1991 : 534. apomorphies (see the cladistic analysis presente d Synonymized with Chernetidae by Judson 1985: 321 . below) . Although the tribe is here regarded a 131 132 THE JOURNAL OF ARACHNOLOGY Myrmochernes Xenochernes Marachemes Maracheme s Marachemes mer is considered apomorphic as the pedipalpa l africanus caxinguba bellus simulans perup setae of other chernetids are either uniforml y 1 3 01 2 clavate or uniformly acuminate (or nearly so) . 01 1 06 15 01 4 The dorsal chelal setae of all Marachernes spp . 02 014 06 07 1 I I I I I are acuminate, whilst they are clavate in My. 0 9 4 08 africanus and X. caxinguba; the former character 03 • 5 01 *4 state is treated as apomorphic (Character 8) . The chelal hand of My. africanus and X. caxinguba 10 is barely wider than the pedicel, in contrast to the narrow pedicel of most other chernetids, in- Figure 1.-Cladogram depicting suggested relation - cluding Marachernes (Character 9) . The chelal ships between Myrmochernes, Xenochernes and Mar- `land of My. africanus, X. caxinguba and Mar- achernes . Closed circle (6) = apomorphy; open circle achernes spp. is barely wider than the base of the (0) = homoplasy; star (*) = polarity uncertain . fingers, an unusual character state amongst cher - netids (Character 10), although not entirely re- stricted to this group. The lack of both accessory My. africanu member of the Chernetinae, further research o n teeth and a venom apparatus in s are very unusual within the family and consid- a wide series of chernetids (not simply those of . a regional fauna) must be undertaken before a ered apomorphic (Characters 11, 12) definitive taxonomic arrangement can be sus- Other characters: The single spermatheca found tained. in My. africanus contrasts with the paired sper- Included species.—Myrmochernes africanus mathecae found in X. caxinguba, Marachernes Tullgren 1907, F'eio 1945 spp. and most other chernetids (Character 13). Xenochernes caxinguba . The smooth anteromedian area of the carapac e Cladistic analysis .—Several characters were seems t scored to determine which could define a clos e found in X. caxinguba and Ma. bellus o have been independently derived from the fully relationship between Myrmochernes and Xen- (Fig. ochernes, and which might be used to determine granulate carapace found in My. africanus whether Marachernes (Harvey 1992a) is relate d 12) and the remaining Marachernes spp. (Char- to these genera (Table 1) . acter 14). The smooth median area of the cara- Chelicerae : As mentioned above, My. african- pace is unique to X. caxinguba (Character 15). As the results of this analysis clearly indicate us and X. caxinguba possess strongly clavate cheliceral setae sbs and bs, which are only den- that Myrmochernes and Xenochernes are very ticulate in Marachernes (Character 1) . The al- closely related, they are here placed in their ow n tribe, Myrmochernetini, within the Chernetinae . most contiguous position of is and is in My. af- e Conversely, there is less evidence for the inclu- ricanus and X. caxinguba is probably uniqu within the tribe. The only amongst chernetids (Character 3), while the lack sion of Marachernes of cheliceral seta es is found only inMy. africanus character state that is likely to support the mono - (Character 2). The number of flagellar blades dif- phyly of all three genera (Character 10) is als o fers between My. africanus + X. caxinguba (three) found in other chernetid genera and is, in fact, very difficult to quantify. Therefore, Marach- and Marachernes spp . (four), with no way of de- termining the plesiomorphic state ; Character 4 ernes is here excluded from the Myrmocherne- is thus left unpolarized. tini, and, remains incertae sedis (along with nu- merous other genera) in the Chernetinae unti l Chelae: The presence of internobasal accessory Mar- further phylogenetic analyses are conducted on teeth on a mound is unique to males of a much wider range of chernetids. achernes spp . (Character 5), although it remain s to be confirmed for Ma. perup Harvey, as male s Genus Xenochernes Feio are not yet known . Trichobothrium est is much Feio 1945 : 37. Type species Xenochernes closer to esb than to et in My. africanus and Ma. Xenochernes caxinguba Feio 1945, by original designation. bellus Harvey (Character 6), clearly the result o f separate acquisitions . The dorsal setae of the pe- Diagnosis.—Differs from all other chernetid dipalpal patella are acuminate in Marachernes genera by the following combination of charac- simulans Harvey and Ma. perup, whilst clavate ters: cheliceral setae bs and sbs clavate, is and is in the remaining species (Character 7) ; the for- nearly contiguous ; female with two spherical HARVEY—PSEUDOSCORPION GENUS XENOCHERNES 133 Table 1 .—Character matrix for Myrmochernes, Xenochernes and Marachernes (see text for explanation) . Myrmo- Xeno - Mara- Mara- Mara- Character: chernes chernes chernes chernes chernes plesiomorphy; apomorphy africanus caxinguba bellus simulans perup 1 . Cheliceral setae sbs and bs: denticulate; clavate 1 0 0 0 2. Cheliceral seta es: present; absent 0 0 0 0 3 . Cheliceral setae is and is : separated; nearly contiguous 1 0 0 0 4. Flagellum, number of blades : 3 3 4 4 4 5. Chelal hand of male, internobasal accessory teeth on mound : absent ; present 0 0 1 1 ? 6. Trichobothrium est much closer to esb than to et: no; yes 0 1 0 0 7 . Pedipalpal patella, dorsal setae: clavate; acuminate 0 0 0 1 1 8. Pedipalpal chela, dorsal setae: clavate; acuminate 0 0 1 1 1 9. Chelal hand: much wider than pedicel; not much wider than pedicel 0 0 0 10. Chelal hand: much wider than base of fingers; not much wider than base of fingers 1 1 1 1 1 11 . Chelal accessory teeth: present; absent 0 0 0 0 12. Venom apparatus : present; absent 0 0 0 0 13. Spermathecae: paired; single 0 0 0 0 14. Carapace, anteromedian area : granulate; smooth 0 1 1 0 0 15. Carapace, median area: granulate; smooth 0 1 0 0 0 spermathecae; chelal hand not much wider tha n median areas which are virtually smooth. Ter- pedicel. gites biseriate . Female genitalia with two round- Description.—Pleural membrane longitudi- ed spermathecae . Legs: all tarsi with subbasal slit nally striate .