Andrognathus Hoffmani, N. Sp., a Second Species in the Genus and the First Species of Andrognathidae from México (Diplopoda, Platydesmida, Andrognathidae)
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Andrognathus hoffmani, n. sp., A Second Species in the Genus and the First Species of Andrognathidae from México (Diplopoda, Platydesmida, Andrognathidae) William A. Shear1 Department of Biology Hampden-Sydney College Hampden-Sydney, Virginia 23943 Paul E. Marek2 Department of Biological Sciences East Carolina University Greenville, North Carolina 27858 Abstract Andrognathus hoffmani, n. sp., is described from near Monterrey, Nuevo León, México, and is the second species of the genus to be discovered; A. corticarius Cope was named in 1869. Anatomical details of both species revealed through scanning electron microscopy are discussed. Contrary to the assertion of Gardner (1975) that the form of the gonopods in the Andrognathidae is of no taxonomic utility, we found striking differences between the two species discussed here, and differences between two populations of nominal A. corticarius. It is possible that A. corticarius as presently understood represents a complex of cryptic species. Key words: Andrognathidae, Andrognathus, Brachycybe, cryptic species, Platydesmida. Introduction have been recorded from Virginia west to Indiana, and from central North Carolina south to northern Florida A surprising number of milliped genera, and even (Gardner 1975, Hoffman 1999), but detailed distribution families, are monotypic, containing but a single species. maps have not been published, nor have populations In recent years, increased interest in diplopods and more from this wide area been carefully examined. Perhaps thorough collecting in many parts of North America have the distinctive body form of A. corticarius, as well as revealed additional species within several of these taxa its small size, inhibited past investigators from looking (e.g., Branneriidae, Shear 2003a; Apterouridae, Shear closely and caused them to assume that all populations 2003b). It is a distinct pleasure to add a second species to were conspecific. yet another milliped genus that has remained monotypic Andrognathus corticarius went substantively for more than a century and a quarter. unmentioned in the literature for 60 years after its The milliped Andrognathus corticarius Cope, 1869 initial description in 1869, until a brief mention and was described as the type of a new genus and family, and inclusion in a key by Cook and Loomis (1928), and then, as now, was one of the most distinctive and unusual the publication of a few additional records by Loomis species of North American millipeds. A member of the (1936). Any new descriptive details, however brief, had Order Platydesmida, this species differs from all others to wait another 47 years until Gardner (1975) published in the order in the peculiar modifications of its tergites, a synopsis of the North American Andrognathidae, but its long, narrow body (about 40 times as long as wide in he focused mostly on the rich and diverse fauna of the adults), and its unexpectedly broad distribution. Specimens western United States. Hoffman (1980) presented a 1 To whom correspondence should be addressed; [email protected]. 2 Present address: University of Arizona, Center for Insect Science, Department of Entomology, Forbes Building, Tucson, AZ 85721, [email protected]. Pp. 155-164, in S. M. Roble and J. C. Mitchell (eds.). 2009. A Lifetime of Contributions to Myriapodology and the Natural History of Virginia: A Festschrift in Honor of Richard L. Hoffman’s 80th Birthday. Virginia Museum of Natural History Special Publication No. 16, Martinsville, VA. 156 FESTSCHRIFT FOR RICHARD L. HOFFMAN revised classification of the family, with a subfamily the sole species of Andrognathinae; Hoffman cited the Andrognathinae for Andrognathus alone, apposed to structure of the fifth diplosegment as the crucial character Dolisteninae and Bazillozoniinae. Shelley et al. (2005) setting off this species from the rest of the family. reviewed Brachycybe—long considered an andrognathid Certainly, in comparison to other genera in the family and genus—and questioned whether or not Andrognathidae even the order, this character is an apomorphy. Except might be divided, probably leaving A. corticarius as for the tribe Mitocybeini (Dolisteninae), new at the time, the sole species under the original family name, with no additional diagnoses were presented. By 1999, he Brachycybe and a few related genera placed in the evidently had become unsure of this arrangement, and new family Bazillozoniidae. Despite Hoffman’s (1980) presented a list of American andrognathid genera in assurances that the problems in the Andrognathidae alphabetical order. Curiously, Hoffman (1980, 1999) were “innocuous” and that “a good revision of the order makes little explicit reference to the posthumously should not be difficult to achieve”, no specialist has published monograph of the Colobognatha by Attems stepped forward to accomplish the task. (1951). This paper is in Gardner’s (1975) bibliography, In 2007, 138 years after the description of A. but goes unmentioned in the text. Despite many corticarius, Casey Richart of Olympia, Washington, sent errors of fact and interpretation, very likely due to the WAS a small collection of millipeds that he made in the incomplete nature of the manuscript at Attems’ death, vicinity of Monterrey, México. Much to our surprise, this monograph must be the starting point for any further a substantial sample of Andrognathus was included, work on platydesmids. and closer examination showed that these specimens It is particularly interesting that Shelley et al. (2005) belonged to an undescribed species. We are delighted detected five geographic clusters of samples of the to dedicate this significant new species to Richard L. andrognathid Brachycybe lecontii Wood (two of these Hoffman on the occasion of his eightieth birthday, and in they referred to as “point” localities—single or a few recognition of his monumental contributions to the study closely clustered samples from a very small area). While of the Diplopoda. suggesting that these clusters represented genetically isolated populations, they did not attempt to assess Family Andrognathidae Cope, 1869 differences between them (morphological or genetic); the clusters were defined on a geographic basis alone. Hoffman (1980) divided Andrognathidae into The distribution of A. corticarius has never been mapped three subfamilies, Andrognathinae, Dolisteninae, and in detail. One questions if similar geographic clusters, Bazillozoniinae. Andrognathus corticarius was listed as potentially representing genetically distinct lineages, Fig. 1. Andrognathus corticarius (below) and ?confamilial Brachycybe lecontii in nature (photographs by P. Marek). SHEAR & MAREK: ANDROGNATHUS HOFFMANI, N. SP. 157 occur in this genus, and if undetected cryptic species paranota arising from anterior part of metazonite, may be present in either Andrognathus or Brachycybe. projecting laterally or posteriorly, peritremata posteriorly Little attention has been paid to the gonopods of the directed. Prozonites with sculpture of small, rounded, platydesmids as possible sources of taxonomic characters. flat tubercles; metazonites with this sculpture variable Cook and Loomis (1928) offered a synopsis of the between species, densely set with short, stout, curved colobognath millipeds of North America, but illustrated setae (Fig. 17). On pleura, sculpture becomes smaller, gonopods for only one species. Gardner (1975) stated tubercles acute-triangular. Sternites narrow, leg coxae flatly that the gonopods of platydesmids were of no use touching or scarcely separated (Figs. 3, 12), sternites taxonomically and provided illustrations only for a single with sculpture of small, acute tubercles raised posteriorly, species of Brachycybe. Shelley et al. (2005) also illustrated with tuberculate knobs anterior to and between leg Brachycybe gonopods for one species, and opined that the coxae (Fig. 7). All leg coxae from third pair posterior peculiarly modified setae of the anterior gonopods might with prominent, eversible coxal glands (Fig. 12). be diagnostic of Brachycybe (these setae actually occur Legless diplosegments anterior to paraproct variable in in a fairly wide range of platydesmidans; see Attems number; one to three in mature animals, lacking sterna, 1951). Working with other colobognath orders, Shelley pleurotergites overlapping in midline (Fig. 5). Epiproct (i.e., 1995) has found the gonopods rich in species- (ultimate segment) cylindrical, without posterior level characters. We have examined the gonopods of a dorsal elongation; hypoproct (ventral preanal scale) few species of colobognaths, including platydesmidans, absent, presumably fused with epiproct; paraprocts using the scanning electron microscope, and at high semihemispherical (Figs. 5, 14). Anterior gonopods magnification under the compound microscope with with six postcoxal podomeres, second podomere with Nomarski differential interference contrast. We found anteriorly-projecting triangular apophyses, distalmost significant differences between nominal species and also podomere forming sheath or guide for posterior gonopod suspect that if samples from various localities occupied stylus; posterior gonopod with six postcoxal segments, by species now thought to have very wide distributions distalmost forming long stylus, form of which varies are so examined, cryptic species may be discovered between species (Figs. 7, 8-10, 18, 19). (Bickford et al. 2007, Pfenninger and Schwenk 2007). Included species: Andrognathus corticarius Cope, A. hoffmani, n. sp. Andrognathus