searchable PDF - Association for Mexican Cave Studies

lobes. The larger setae vary greatly in size and occuras simple pointed structures, or somewhat flattenedwith pilose borders, or as round pointed structureswith pilose distal ends. Harvey (in press) noted therecurring pattern of setae and introduced the firstnotation for labeling the larger setae on the flagellumof schizomids (Hubbardiidae of Australia).While protoschizomids have all of the setae noted byHarvey, several other setae can be found on protoschizomidflagella, thus necessitating a renumberingof the setae. We have attempted to correlate ournumbers with those of Harvey. Whereas Harveyonly numbered larger setae, we have attempted tonumber all setae (except a tenninal microseta, whichis difficult to observe). We have done this becausesome setae will be microsetae on some species andlarger setae on other species.Female flagellum: Dorsal surface bearing up tofive medial setae [dml, dm2, dm3 (pair of setae),dm4] and up to four pairs of lateral setae (dll, d12,d13, dI4). Ventral surface bearing up to eight medialsetae [vml, vm2 (pair of setae), vm3 (submedialpair of setae), vm4 (pair of setae), vmS] and twopairs of ventrolateral setae (vII, vI2). From therelative positions on the adult female flagellum, thefollowing correlations are suggested [Harvey (inpress) = present system]: dml=dml, not present=dm2,not present=dm3, dm2=dm4, dll=dll,not present=dI2, dI2=dI3, not present=dI4,vml =vml, vm2=vrn2, not present=vm3,vm3=vm4, vm4=vmS, vll =vll, vI2=vI2. Thelateral setae are variable as to position and often appearto switch positions from dorsolateral to ventrolateral.An alternate hypothesis is that the said setaeare not homologous and represent losses and gains,respectively. Since this would involve two steps(loss and gain) we feel it is more parsimonious toassume a shift in position. Several setae are shortand sometimes thinner in the Protoschizomidae:dm3, dll, d14. In some specimens dl4 appear to bemicrosetae. A single microseta (larger in A. pateifemales), which we have not numbered, is oftenpresent on the most terminal area of the flagellum.Male flagellum: The setation is similar, but neverexactly the same as in females. In A patei, severalpairs of setae have shifted to a ventral position. Thisshift is not noted in females or other males. Possiblythe presence of ventrolateral lobes in the otherspecies precludes the varying of setae. Numberingof setae is greatly aided by noting that vm3 areusually off-eentered and that dm3, dll, and dl4 aregenerally small in size.There are five positions on the female flagellumof schizomids where annuli can occur. These areasmay be evident as thinnings of the cuticle(sometimes only on ventral surface) or as cleanbreaks in the cuticle. We have numbered these areas,based on the genus with the greatest number of annuli(Megaschizomus), to standardize our descriptionsand discussion (Fig. Ic). The positions of theannuli are always in the same place relative to thelarger setae: segment I contains no setae; segment IIwith dml, dm2, dll, vml-vm3; segment III withdm3, vm4; segment IV with dm4, d12, vll, andsegment V with d13, d14, vmS, v12. Position 2 annulifound in Hubbardiidae do not occur in protoschizomids.The distinction between segments andarticles is not entirely clear. When examined underlOOx the divisions between segments appear asbreaks in the cuticle. The lines are generally thinand sometimes difficult to see. No musculature isevident and it is unlikely that these segments can bemoved. Attempts to bend the flagellum at a segmentaljunction in a preserved specimen result in a cleanbreak at that border. Subdivisions of the segmentsare evident by areas of thinned cuticle. These zonesare sometimes quite wide and appear lighter in colorthan the surrounding cuticle. Segments do not appearto break at these subdivision zones and in preservedspecimens this zone will withstand somebending. When the flagellum is divided by breaks inthe cuticle we refer to the resulting subdivisions assegments. When a segment or entire flagellum isdivided by only thinnings in the cuticle we refer tothe resulting units as articles. Annuli are alsopresent in juveniles but not in the flagellum of maturemales.The following acronyms have been used to designatemuseums in which the specimens are deposited:AMNH - American Museum of Natural History,New YorkCAS - California Academy of Sciences, SanFranciscoTMM - Texas Memorial Museum, Austin (allspecimens formerly reported in the collection ofTexas Tech University have been transferred toTMM).Character relationships were first examined usingMcClade (Maddison and Maddison, 1987). An exactanalysis was performed using Hennig86 (Farris,1988) which is "guaranteed" to find all of the mostparsimonious cladograms. All multistate characterswe treated as non-additive (unordered). To attemptto reduce the ambiguity of the strict consensus,successive approximations character weighting wasapplied. Because none of the characters conflicted,this produced identical results. Autapomorphiccharacters were not coded for the matrix. By doing33