2004. The Journal of Arachnology 32:432±435

DESCRIPTION OF THE FEMALE OF ACROPSOPILIO CHOMULAE (GOODNIGHT & GOODNIGHT 1948) FROM CHIAPAS, MEXICO (OPILIONES, CADDIDAE, ACROPSOPILIONINAE)

William A. Shear: Department of Biology, Hampden-Sydney College, Hampden- Sydney, Virginia 23943 U.S.A.

ABSTRACT. The tiny caddid harvestman Acropsopilio chomulae (Goodnight & Goodnight 1948), from Chiapas, Mexico, has been known only from the immature holotype. Mature females are described from specimens taken near the type locality. The absence of spermathecae in the ovipositor makes it likely that the species is parthenogenic.

RESUMEN. Hasta el momento, los uÂnicos datos disponibles del pequenÄo opilioÂn Acropsopilio chomulae (Goodnight & Goodnight 1948) de Chiapas (MeÂxico) proceden del estudio del holotipo, un ejemplan inmaduro. En este trabajo se describen hembras maduras procedentes de cerca de localidad tipica. La ausencia de espermateca en el oviscapto sugiere que la especie es partenogeneÂtica. Keywords: North America, harvestman, parthenogenesis

In my 1975 revision of the harvestman fam- Casas (92Њ36 W, 16Њ42ЈN), 25 August 1966, ily Caddidae (Shear 1975), I was unable to W. & J. Ivie (AMNH). treat the interesting species Acropsopilio cho- Description of female.ÐTotal length, 1.14 mulae (Goodnight & Goodnight 1948) in de- mm; width of eye tubercle, 0.42 mm. Eye tu- tail because the immature holotype was the bercle occupies entire propeltidium when seen only available specimen. Having described the from above, projecting considerably over che- species as Caddo chomulae in 1948, Good- licerae, deeply impressed in median line. Eyes night and Goodnight later (1950) mentioned 0.17 mm in diameter, slightly protruding, cir- collecting numbers of mature individuals, but cular. Free thoracic tergites (meso- and meta- when I enquired in the early 1970s, they could peltidium) only slightly distinct when seen not locate this material, and the present from above (for general form of body, see whereabouts of these specimens remains un- Shear 1975, ®g. 10). Body soft, not heavily known. However, the American Museum of sclerotic, devoid of spines or tubercles. La- Natural History (AMNH) has a small collec- brum triangular, pointed, large. Coxae and en- tion of this species made near the type locality dites as in A. boopis (Crosby 1904) (Shear by Wilton and Jean Ivie. I take this opportu- 1975, ®g. 7), but endites of coxae II in some nity to describe these specimens. specimens entirely separating endites of coxae I from their coxae. Genital operculum large, TAXONOMY broad, bluntly pointed. Sternum not sclero- tized. Spiracles vestigial, closed. Family Caddidae Banks 1892 Palpus (Fig. 1) longer in proportion to body Subfamily Acropsopilioninae Roewer 1923 Acropsopilio chomulae (Goodnight & length in mature specimens than in juvenile Goodnight 1948) holotype. Palpal trochanter with one promi- Figs. 1, 2 nent seta and several smaller ones. Femur 0.67 mm long, 0.10 mm wide, with characteristic Caddo chomulae Goodnight & Goodnight 1948: group of three seta-bearing tubercles near 201. base, single seta-bearing tubercle near midline Acropsopilio chommulae (sic): Ringuelet 1962:79. Acropsopilio chomulae: Shear 1975:79. and at femoral apex on mesal side, brushlike group of small setae on lateral side about two- Material examined.ÐMEXICO: Chiapas: thirds from base of femur. Patella 0.34 mm 8 &, from 4 miles east of San Cristobal de las long, 0.10 mm wide; tibia 0.32 mm long, 0.10

432 SHEARÐACROPSOPILIO CHOMULAE FEMALE 433

Figures 1, 2.ÐAcropsopilio chomulae female: 1. Right palpus, mesal view; 2. Ovipositor, ventral view. mm wide, with 10±12 glandular setae ven- and tibia, from A. venezuelensis Gonzales- trally. Tarsus 0.25 mm long, 0.10 mm wide; Sponga 1992 in having the apical spined tu- with small, immobile, vestigial claw, 20±24 bercle of the palpal femur close to the distal glandular setae ventrally. end rather than set back about 1/3 the length Legs relatively short and thin, leg IV much of the femur, from A. chilensis in having the the longest. Femora I±IV 0.38, 0.57, 0.50, palpal tarsus shorter than the tibia, and from 0.76 mm long respectively; tibiae I±IV 0.25, A. neozealandiae (Forster 1948) in stronger 0.30, 0.34, 0.44 mm long respectively. spined tubercles at the palpal femur base. In Ovipositor (Fig. 2) short, membranous, overall appearance and especially palpal mor- with two rings marked by apical transverse phology, chomulae most closely resembles rows of setae, valves irregularly setose, sen- neozealandiae. sillum single, apically bifurcate seta. Seminal Recently, I brie¯y summarized the bioge- receptacles not detected. ography and evolutionary relationships of the Color light brown, darker on abdominal acropsopilionines (Shear 1996). Writing that dorsum, eye tubercle pale tan, eyes broadly paper, I was not aware of the description by ringed in black, palpus with femur and patella GonzaÂlez-Sponga (1992) of Acropsopilio ve- striking pure white, tibia and tarsus dark nezuelae, from northern South America. This brown, legs medium tan. species provides a biogeographic link between A. chilensis Silvestri 1904 in southern South DISCUSSION America and the northern hemisphere species As implied from an earlier description of A. chomulae and A. boopis. GonzaÂlez-Spon- the juvenile holotype, A. chomulae is a dis- ga's discovery, the ®nding of Austropsopilio tinct species. It differs from A. boopis in hav- sudamericanus Shultz & Cekalovic 2003 in ing no spined tubercles on the palpal patella Chile and Argentina (Cokendolpher & Maury 434 THE JOURNAL OF ARACHNOLOGY

1990; Shultz & Cekalovic 2003), and the de- (Maury et al. 1996; these authors evidently scription of Hesperopilio mainae Shear 1996 did not check for spermathecae). A single from Western Australia (Shear 1996) remind male is known for A. venezuelae GonzaÂlez- us that much fundamental data remains to be Sponga 1992 (GonzaÂlez-Sponga 1992), and collected concerning these minute, relictual, there is always the possibility that males of hard-to-®nd harvestmen. The trans-Paci®c the ``females only'' species are very short- distribution of several of the genera makes lived, occupy a different habitat or simply these animals important in establishing zoo- have not been collected. I believe that parthe- geographical connections between Australia nogenesis for A. chomulae represents the best and temperate southern South America. hypothesis, though it is dif®cult to prove a Ovipositors of Acropsopilio chomulae were negative±the complete absence of males. Only mounted temporarily on microscope slides laboratory rearing can answer the question de- and examined under oil immersion and No- ®nitively, and the caddids, with their require- marski differential interference contrast, on an ments for cool, moist conditions, are very dif- Olympus BX50 microscope. No spermathecae ®cult to keep alive in captivity. were seen, as is the case with A. boopis. The A thorough comparative study of the male absence of these structures makes it likely (but genitalia in the caddoids is lacking, and a re- not certain; see Bertani & Silva Junior 2002) markable range of variation in basic design is that A. chomulae is parthenogenic. Partheno- present. Most of the species for which penes genesis is common in the Caddidae, but sex- have been illustrated have organs with heavily ual species also occur, in a complex mosaic. sclerotized, movable macrosetae (Hesperopi- Caddo agilis Banks 1892 females lack sper- lio mainae Shear is an exception). The spiny mathecae, and only three males have ever penes are closest in form to those of the Neo- been found among hundreds of specimens pilionidae, which, like the caddoid penes, fea- (Gruber 1974; Suzuki & Tsurusaki 1983). ture movable macrosetae. Neopilionids also Caddo pepperella Shear 1975 may be a pro- have glandular-plumose hairs on the adult pal- genic isolate of agilis that arose after parthe- pi (Hunt & Cokendolpher 1991). nogenesis had become established; males are No comparative information is available on unknown, spermathecae are lacking. The pro- the respiratory systems of Acropsopilio spe- genesis event may have happened at least cies, but the spiracles of A. chomulae are twice, since the species is known from a small small and imperforate. One specimen was sac- region of eastern North America and from Ja- ri®ced in order to look for tracheae, and none pan (Shear 1996). Caddo agilis has an Oli- were found. Such a small animal with its thin gocene fossil record (Shear 1975) from Eu- cuticle, living in a constantly humid environ- rope, so it is less likely that the origin of agilis ment, may be able to satisfy its respiratory from pepperella took place via peramorpho- needs by diffusion through the body wall. sis. Males are known for two of the three South LITERATURE CITED African species of Caddella (Shear 1975), and Bertani, R., & P.I. da Silva Junior. 2002. The ®rst for Hesperopilio mainae (Shear 1996). mygalomorph spider without spermathecae: Sic- Males have been described for Austropso- kius longibulbi, with a revalidation of Sickius pilio fuscus (Hickman 1957), but for no other (Araneae, Theraphosidae, Ischnocolinae). Jour- species of the genus; females of A. fuscus nal of Arachnology 30:519±526. have spermathecae. Despite the highly de- Cokendolpher, J.C., & E.A. Maury. 1990. Austrop- tailed description, Shultz and Cekalovic sopilio harvestmen (Opiliones, Cyphopalpatores, (2003) did not mention ®nding spermathecae Caddidae) discovered in South America. BoletõÂn in A. sudamericanus, which is known only de Sociedad BiologõÂa ConcepcioÂn, Chile 61:59± from females. 62. Goodnight, C.J., & M.L. Goodnight. 1948. A new Acropsopilio boopis males have never been member of the genus Caddo (Phalangida). Jour- collected either in North America (Shear nal of the New York Entomological Society 56: 1975) or Japan (Suzuki 1976; Suzuki & Tsu- 201±203. rusaki 1983), and A. chilensis, widespread in Goodnight, C.J., & M.L. Goodnight. 1950. Grant southern South America (Brazil, Chile, Ar- No. 1219 (1950), distribution and taxonomic re- gentina), is likewise known only from females lationships of the phalangid fauna of Chiapas, SHEARÐACROPSOPILIO CHOMULAE FEMALE 435

Mexico. Year Book of the American Philosoph- al de Punta Lara y la ubicacõÂon taxonoÂmica de ical Society 1950:142±145. geneÂro Acropsopilio Silvestri. Physis 23:77±81. GonzaÂlez-Sponga, M.A. 1992. AraÂcnidos de Vene- Shultz, J.W. & T. Cekalovic. 2003. First species of zuela. Nueva especie del geÂnero Acropsopilio de Austropsopilio (Opiliones, Caddoidea, Caddidae) la Cordillera de la Costa (Caddidae). BoletõÂn de from South America. Journal of Arachnology 31: la Academia de Ciencias FõÂsicas, MatemaÂticas y 20±27. Naturales 52:43±51. Shear, W.A. 1975. The opilionid family Caddidae in North America, with notes on species from Gruber, J. 1974. Bemerkungen zur Morphologie other regions (Opiliones, Palpatores, Caddoidea). und systematischen Stellung von Caddo, Acrop- Journal of Arachnology 2:65±88. sopilio und verwandter formen (Opiliones, Shear, W.A. 1996. Hesperopilio mainae, a new ge- Arachnida). Annalen Naturhistorisches Museum nus and species of harvestman from Western in Wien 78:237±259. Australia (Opiliones: Caddidae: Acropsopilioni- Hunt, G.S., & J.C. Cokendolpher. 1991. Ballarrinae, nae). Records of the Western Australian Museum a new subfamily of harvestmen from the South- 17:455±460. ern Hemisphere (Arachnida, Opiliones, Neopilio- Suzuki, S. 1976. The harvestmen of family Caddi- nidae). Records of the Australian Museum 43: dae in Japan (Opiliones, Palpatores, Caddoidea). 131±169. Journal of Science of Hiroshima University, Se- Maury, E.A., R. Pinto da Rocha & J.J. Morrone. ries B, Division 1 (Zoology) 26:261±273. 1996. Distribution of Acropsopilio chilensis Sil- Suzuki, S. & N. Tsurusaki. 1983. Opilionid fauna vestri, 1904 in southern South America (Opilio- of Hokkaido and its adjacent areas. Journal of Science of Hiroshima University, Series B, Di- nes, Palpatores, Caddidae). Biogeographica 72: vision 1 (Zoology) 23:195±243. 127±132. Ringuelet, R.A. 1962. Notas sobre Opiliones. I. Manuscript received 9 September 2003, revised 24 Acropsopilio oglobini Canals en la selva margin- November 2003.