PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024 Number 3579, 44 pp., 119 figures, 4 maps June 28, 2007 A Revision of the Spider Genus Zorocrates Simon (Araneae, Zorocratidae) NORMAN I. PLATNICK1, AND DARRELL UBICK2 ABSTRACT The spider genus Zorocrates is revised, and comprises at least 31 species found from the southern United States south to Central America; it provides a notable example of the loss of a functional cribellum within a relatively small (but seemingly monophyletic) group of species. Two specific names are removed from synonymy: Z. gnaphosoides O. P.-Cambridge and Z. mordax O. P.- Cambridge (from Z. fuscus Simon and Z. mistus O. P.-Cambridge, respectively). Two other specific names are newly synonymized: Z. isolatus Gertsch and Davis, with Z. unicolor (Banks), and Z. petersi Kraus, with Z. gnaphosoides O. P.-Cambridge. Males are newly described for Z. badius Simon and Z. pictus Simon; females are newly described for Z. karli Gertsch and Riechert. Twenty new species are described from Texas and Mexico. INTRODUCTION 21, just as an entry in a key couplet), to include the New World Zorocrates plus four The American spiders of the genus Old World genera that had been placed by Zorocrates Simon (1888) are of considerable Lehtinen in the Miturgidae instead. Because phylogenetic interest. They were originally the genus has never been revised, identifica- described as members of the Old World family tion of the specimens used as exemplars in Zoropsidae. Lehtinen (1967) transferred the modern phylogenetic studies, such as those of genus to the New World family Tengellidae, Griswold (1993), Silva (2003), Raven and but Griswold et al. (1999) revived the name Stumkat (2005), and Griswold et al. (2005), Zorocratidae, first proposed by Dahl (1913: has been problematic. 1Peter J. Solomon Family Curator, Division of Invertebrate Zoology, American Museum of Natural History; Adjunct Professor, Department of Biology, City College, City University of New York; Adjunct Professor, Department of Entomology, Cornell University; Adjunct Senior Research Scientist, Center for Environmental Research and Conservation, Columbia University ([email protected]). 2Associate, Department of Entomology, California Academy of Sciences, 875 Howard Street, San Francisco CA 94103 ([email protected]). Copyright E American Museum of Natural History 2007 ISSN 0003-0082 2 AMERICAN MUSEUM NOVITATES NO. 3579 Zorocrates species are also of phylogenetic John A. Murphy (JAM), Museum of interest because of the variation in their Comparative Zoology, Harvard University cribellar structure. The group has always been (MCZ), Muse´um National d’Histoire Nature- considered cribellate, but we describe below lle, Paris (MNHN), Natur-Museum Sencken- two new species from the Xilitla Plateau in berg (NMS), New Mexico State University, San Luis Potosı´ that, despite having male and Las Cruces (NMSU), Texas A&M University, female genitalia indicating that they are well College Station (TAMU), University of nested within the genus, are fully ecribellate. California at Riverside (UCR), Universidad Although examples of cribellate and ecribel- Nacional Auto´noma de Me´xico (UNAM), late sister genera have been noted over recent and National Museum of Natural History, decades, loss of the cribellum within a single Smithsonian Institution (USNM). genus seems less common. Unsurprisingly, though, similar losses of the cribellum have RELATIONSHIPS apparently occurred within the Malagasy zorocratid fauna (C. Griswold, personal com- The relationships of Zorocrates remain ill- mun.). defined, as the most recent phylogenetic In addition to the variation in cribellar analyses have reached somewhat different structure, Zorocrates specimens have some- conclusions. In the analysis by Silva (2003: times been difficult to place (at least in keys) fig. 6), Zorocrates clustered more closely with because of their unusual tarsal configuration. the cribellate, New World genus Tengella Several authors (e.g., Gertsch and Riechert, Dahl (1901) than with the other genera 1976; Roth, 1985; Griswold and Ubick, 2001) currently placed in the Zorocratidae, which have indicated that the unpaired tarsal claw is in her taxon sampling were represented by present only on the anterior pair of legs, and Uduba Simon (1880), Raecius Simon (1892), absent on the posterior three pairs. The tarsi and Zorodictyna Strand (1907). The fifth are heavily scopulate and the tarsal claws are current zorocratid genus, Campostichomma often obscured by the dense, distal scopular Karsch (1891), was not included in her matrix. hairs; it is difficult to remove the scopular In the analysis by Raven and Stumkat hairs without also damaging the claws. (2005), however, Griswold’s (1993) grouping However, detailed examination of many speci- of Zorocrates with the other five genera was mens leads us to conclude that the unpaired retrieved (with Tengella widely disparate, and claw is probably always present, although it is a minor rearrangement involving Zorodictyna, typically reduced to just a tiny projection which clustered not with Raecius but with the (Griswold et al., 2005: fig. 146A). Roth (1993: other three genera). 168) seemed to have reached the same The most recent study, by Griswold et al. conclusion, for he changed his earlier account (2005), included as terminals Tengella, Uduba, to read ‘‘tarsi I 3-clawed, and II-IV 2-clawed, and Raecius, as well as Zorocrates. Under often with a minute third claw.’’ Because the implied weighting, Zorocrates clustered with third claw can be so easily overlooked, speci- Tengella, on the basis of deeply notched mens have even been described as dionychans trochanters; this group was resolved as sister (see the note on Chemmis unicolor Banks, to a group including Raecius, Uduba, Zoropsis, 1901, below). and Acanthoctenus Keyserling (1877, a cribel- The format of the descriptions follows that late member of the family Ctenidae). Under of Platnick (1999). Specimens have been equal weights, Zorocrates was placed at an examined from the collections of the Ameri- unresolved node subtending all those taxa plus can Museum of Natural History (AMNH), Psechrus Thorell (1878), the cribellate type Natural History Museum, London (BMNH), genus of the family Psechridae. California Academy of Sciences, San Fran- These results are all equivocal, however, cisco (CAS), David Bixler (CDB), Darrell because almost all the characters involved show Ubick (CDU), Centro de Investigaciones high degrees of homoplasy, and the clades Biological del Noroeste, La Paz (CIBN), Joe resolved can therefore be perturbed easily by Beatty (CJB), James Cokendolpher (CJC), changes in the matrix or analytical methods 2007 PLATNICK AND UBICK: SPIDER GENUS ZOROCRATES 3 (e.g., character weighting). Similarly, the cur- and anterior lateral eyes that are larger than rent limitation of the Zorocratidae by Griswold the anterior medians. By the abdominal shield, et al. (1999) was based on a phylogenetic those authors meant a sclerotized scute analysis that included only the genera Tengella, associated with the paired transverse sigilla Uduba, and Raecius. In that analysis, three found on the anterior face of the abdomen; characters supported the placement of Uduba such scuta also do not occur in Zorocrates, and Raecius as sister taxa: the male tibial crack where the sigilla are no more conspicuous in (a character discovered by Griswold, 1993: figs. males than in females. Zorocrates males also 3, 4, that allows a distinctive form of leg lack another character figuring in their revised breakage), clumped cribellar spigots, and familial diagnosis, a dense dorsal scopula on a ventroapical apophysis on the male palpal the palpal cymbium. tibia. Those same three characters were there- The results of Raven and Stumkat, and of fore cited by Griswold (2002: 118) as synapo- Silva, are similar in positing that either morphies for the Zorocratidae. Zorocrates (in the first case) or both Unfortunately, Zorocrates itself has none Zorocrates and Tengella (in the second case) of those presumed apomorphies of the have lost grate-shaped tapeta in their posterior Zorocratidae. The tibial crack and ventroapi- median eyes, and have reverted to the more cal apophysis are absent (Silva, 2003: char- plesiomorphic, canoe-shaped tapetum. Be- acters 93 and 4, respectively), and the cribellar cause of the weak support from only highly spigots are uniformly distributed rather than homoplasious characters, and the resultingly clumped (Griswold et al., 2005: fig. 101B). unstable results, Silva refrained from making The association of Zorocrates with Tengella nomenclatorial changes reflecting this hypoth- instead was similarly based only on three esis. That seems wise to us, and we similarly homoplasious characters (oval anterior lateral prefer to retain, at least temporarily, the eyes, and the presumed loss of male tibial family Zorocratidae, even though it may cracks, for Silva, 2003: characters 87 and 93, prove eventually to be a junior synonym of respectively; deep trochanteral notches, for the Tengellidae, Zoropsidae, or both. That Griswold et al., 2005: character 11). Anterior retention reflects the possibility that on-going lateral eyes that are oval rather than round analyses of family-level relationships across all occur in most ctenids as well as these two spiders, currently being conducted under the genera, but the feature shows slightly less Assembling the Tree of Life initiative, may homoplasy than Silva