Allen R. Brady.
Psyche 86:167-212, 1979.

Full text (searchable PDF, 5676K)
Durable link: http://psyche.entclub.org/86/86-167.html

The following unprocessed text is extracted from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

NEARCTIC SPECIES OF THE WOLF SPIDER
GENUS TROCHOSA (ARANEAE: LYCOSIDAE)*
BY ALLEN R. BRADY
Department of Biology, Hope College
Holland, Michigan 49423
This is the first in a projected series of systematic studies of the Nearctic Lycosidae described in the genra Trochosa and Lycosa. One important aspect of the proposed series of revisions will be an attempt to delimit generic taxa within the Lycosidae, with special reference to Nearctic species. Over 50 species of North American Lycosa have been described and most of the medium to large- bodied wolf spiders are included in this genus at present. However, preliminary studies indicate that several distinct species groups, which may well represent different genera, have been assembled under Lycosa. Before undertaking the larger and more complicated task of delimiting genera within the Lycosa complex, it seemed logical to gain some idea of generic limits-to develop a yardstick whereby the species groups of Lycosa could be measured. Trochosa is represented by a small, relatively well-defined, widespread group of species. This genus might well serve as a model and yardstick for the study of Lycosa and I thought it practical to begin here. The genus Trochosa is represented by five species in the Nearctic Region. One of the species, T. terricola, is quite common in Western and Central Europe (Locket and Millidge 1951, Engelhardt 1964, Fuhn and Burlacu 1971) and very likely occurs throughout the tem- perate parts of the Holarctic Region. The other four species com- prise a distinct group that is probably restricted to North America. Trochosa avara occurs from the eastern coast westward to the 100th parallel, while Trochosa gosiuta is found in the southwestern United States (Map 2). Trochosa shenandoa occurs along the Atlantic and Gulf coasts and extends inland in the central United States as far as Kansas and possibly Illinois (Map 3). Trochosa parthenus appears in the southeastern United States and is the only species found in the Florida peninsula (Map 3).
North American species of Trochosa, with the exception of she- nandoa, have been relegated to the genus Lycosa at one time or 'Manuscript received by the editor November 16, 1979.



================================================================================

168 Psyche [June-September
another. They do share some features with certain members of that large aggregate, but can be grouped together and distinguished from other lycosids on the basis of characteristics delineated in the preliminary diagnosis of the genus and the discussion of species groups.
Trochosa C. L. Koch
Trochosa C. L. Koch, 1848: 95; 185 1 : 33. Type species by original designation Arenea ruricola DeGeer, 1778. Keyserling 1877: 610. Scudder 1882: 328. Marx 1890: 564. McCook 1894: 90, 100, 107, 1 12, 118. Montgomery 1904: 300. Banks 1905: 3 19. Petrunkevitch 1928: 250.
Trochosina Simon, 1885: 10 (subgenus of Trochosa). Type species by original desig- nation Trochosa terricola Thorell, 1856. Roewer 1954: 302 (raised to generic status).
Varacosa Chamberlin and Ivie, 1942: 36 (subgenus of Trochosa). Type species by original designation Trochosa avara Keyserling, 1877. Roewer 1954: 304 (raised to generic status). NEW SYNONYMY
Allohogna (part). Roewer, 1954: 2 12.
Allotrochosina Roewer, 1954: 2 13. Type species by monotypy. Lycosa maunganui- ensis Berland, 1925 (misspelled mananganuiensis by Roewer). Diahogna Roewer, 1954: 239. Type species by monotypy Lycosa martensii Karsch, 1878.
Trochosomma Roewer, 1954: 304. Type species by original designation Trochosa annulipes L. Koch, 1875.
Discussion. For a more complete listing of synonyms of Trochosa by European authors refer to Bonnet (1959: 4698-4699). Trochosina Simon, Allotrochosina Roewer, and Diahogna Roewer were syn- onymized by Guy (1966) and his findings are supported here. Tro- chosomma Roewer was synonymized by McKay (1979). Characteristics. Small to medium size spiders (total length 5.8 to 13.0 mm). Carapace length 3.2 to 5.9 mm; width 2.4 to 4.3 mm. Color brownish yellow to dark brown with a lighter submarginal stripe on each side of the carapace and a broad median light stripe as in Figures 1-6. Within the light median stripe appears a pair of dark short stripes or dashes as in Figures 1, 2, 3, 5, 6. Trochosa gosiuta (Fig. 4) is the only species that does not show these dashes so characteristic of the genus. With this exception the dorsal pattern is similar throughout the genus. Abdomen yellowish brown to brown ground color with darker brown or black markings; sometimes with indistinct chevrons, but mostly mottled as in Figures 1-6. Eyes: Anterior median eyes (AME) larger than anterior lateral eyes (ALE). Posterior median eyes (PME) larger than posterior



================================================================================

19791 Brady - Spider Genus Trochosa 169
lateral eyes (PLE), both much larger than anterior eyes. Eye arran- gement: anterior eye row slightly procurved, equal or subequal (less than 0.02 mm difference) to PME width. PME width less than PLE width. PME width greater than length of posterior ocular quadran- gle (POQ).
Cephalothorax relatively flat when viewed from the side, tapering downward slightly in cephalic region.
Legs relatively short when compared to carapace length (ratio derived by dividing length of leg IV by carapace length 2.4 to 3.2 in females and 2.6 to 3.3 in males). Order of leg length IV-1-11-111. Order of length of segments: patella-tibia IV-metatarsus IV- patella-tibia I in avara group; patella-tibia IV-patella-tibia I- metatarsus IV in terricola. Trochosa terricola males have patella- tibia I longer than patella-tibia IV.
Posterior cheliceral teeth 3-3 in avara group, variable in terricola (Map 1 and Table 1).
Epigynum of female with median septum (ms) in shape of inverted "T" (Fig. 25). The longitudinal piece (lp) broad and flat in terricola (Fig. 13) or narrow with a bulbous white structure (b) filling most of the atrium in the avara species group (Fig. 27). In the latter species the transverse piece (tp) of the medium septum has the ends curved anteriad.
Palpus of male with palea (p) partly sclerotized (Fig. 46) or heav- ily sclerotized with prominent distal knob (Fig. 40). Embolus (e) arising on distal or prolateral margin of palea with long intromittent part curled distally into a loop (Fig. 30) or with broad pars pendula (pp) and a short intromittent part angled distally (Fig. 45). Conduc- tor (c) prominent, broad, and concave (Fig. 42). Median apophysis (ma) well developed, conspicuously enlarged and directed ventrad in some species (Fig. 43).
Diagnosis. As described above, representatives of the genus Tro- chosa differ from those of other lycosid genera primarily in the distinctive color pattern of the carapace. In addition the first eye row, which is essentially equal in width to the PME row, the low carapace that slopes downward anteriorly, and the relatively short legs are features that distinguish Trochosa from other lycosid gen- era. The relative dimensions of the eye rows compared to one another, and the carapace dimensions compared to leg length are



================================================================================

170 Psyche [June-September
quite similar in Trochosa species; and once known for all genera of North American lycosids these ratios may help to set apart Tro- chosa, as well as other genera.
Although the ecology and behavior of North American species of Trochosa have not been well studied, there is enough information to indicate similarities in habitats and phases of life history. All North American species of Trochosa inhabit edge of woods or open wood- land habitats (as do a number of their Palaearctic relatives). None of the American Trochosa are burrowers, such as Geolycosa and many species of Lycosa. Both Trochosa terricola and avara are often found under logs or stones, where they presumably molt and con- struct egg cases. These ecological and behavioral features also serve to separate species of Trochosa from many other lycosids. Species Groups. The structure of the male palpus and the female epigynum are often diagnostic at the generic level in spiders. In the case of Trochosa the genitalia delimit two species groups: ruricola, robusta, spinipalpis, and terricola on the one hand; and avara, gosi- uta, shenandoa, and parthenus, on the other hand. In Trochosa terricola the male is recognized by the long, thin embolus forming a loop at its distal end (Fig. 30) and the female by the broad inversely "T-shaped" epigynum (Figs. 13, 14, 16). Trochosa ruricola, robusta, and spinipalpis of Europe are very similar to terricola in genitalic structure (see Locket and Millidge 195 1, Engelhardt 1964, Fuhn and Burlacu 1971). In North America terricola is the lone member of the ruricola species group and is easily differentiated from other species of Trochosa in this region by genitalic structure. Trochosa avara females are recognized by the epigynum which has the ends of the transverse piece directed anteriad (Figs. 20, 21). This feature is characteristic of females of the avara group (Figs. 18, 23, 25, 27) and separates them from all other North American Lyco- sidae. A unique feature of the males in the avara group is the embo- lus which expands into a broad flattened, semi-transparent plate as it curves beneath the palea and then narrows to form a filament that coils into the concavity of the conductor (Figs. 34, 36, 39, 42, 45). The twist at the tip is reminiscent of the embolus in terricola. Des- pite the differences in structure of the male and female genitalia of terricola when compared with representatives of the avara group, the close correspondence in color patterns, particular morphologi- cal features, and certain ecological characteristics warrant their inclusion in a single genus.




================================================================================

Brady - Spider Genus Trochosa
Species Excluded from Trochosa
The following North American species have been placed in Tro- chosa by previous authors, but they do not belong in this genus as it is diagnosed here.
Lycosa animosa Walckenaer, 1837. Placed in Trochosa by Simon (1864) = Anahita animosa (Walckenaer)
Trochosa cherokee Chamberlin and Ivie, 1942 = Lycosa chero- kee (Chamberlin and Ivie)
Lycosa contestata Montgomery, 1903. Placed in Trochosa by Montgomery (1904) and synonymized by Chamberlin ( 1909) with Lycosa pratensis Emerton, 1885 = Lycosa contestata Montgomery
Lycosa frondicola Emerton, 1885. Placed in Trochosa by Mont- gomery (1 904) = Lycosa frondicola Emerton Lycosa similis Banks, 1897. Synonymized by Banks (19 l6b) with Lycosa pratensis Emerton, 1885 = Lycosa similis Banks Lycosa animosa Walckenaer was transferred to the genus Ana- hita of the Family Ctenidae by Chamberlin and Ivie (1942). John Abbot's Figure 8 1, the figure upon which the name Lycosa animosa is based, in the Spiders of Georgia (1792) is not Trochosa. Chamber- lin and Ivie are probably correct in their diagnosis. The female holotype of Trochosa cherokee Chamberlin and Ivie from the American Museum of Natural History (AMNH) was examined. It belongs to the Lycosa gulosa species group. The holotype of Lycosa contestata Montgomery from the AMNH was examined. It is an immature female belonging to the Lycosa helluo species group. Numerous specimens of Lycosa frondicola were examined, samples were measured, and detailed drawings made for comparison to spe- cies of Trochosa. I concluded that frondicola is best placed in Lycosa at present. The holotype of Lycosa similis Banks from the Museum of Comparative Zoology (MCZ) was examined. It is an immature female belonging to the Lycosa helluo species group. In addition to the above species, type specimens of Lycosa abdita Gertsch from the AMNH and Lycosa acompa Chamberlin from the MCZ were examined because of certain Trochosoid characters they possessed. They do not belong in Trochosa as it is conceived here.



================================================================================

Psyche
[June-September
Spider systematists, in general, employ many of the same tech- niques and methods in their study of materials. Basically a number of measurements of bodily components are made and characters of taxonomic importance are illustrated. These measurements and drawings characterize the species under investigation and aid in their identification and separation from closely related forms. Some idea of the phylogenetic relationships of species can be gained from this information as well.
It is often taken for granted by the specialist that others outside his field know about the techniques and methods employed and the rationale behind them. Since this is not necessarily true, and since this is the first in an anticipated series of systematic revisions on the Lycosidae, I decided to explain some of the details involved in the study. The methods and rationale set forth here will be a basis for future investigations. The subheadings below include the compo- nents explored in the analysis of each species. Discussion. Under this subheading an attempt is made to clarify the nomenclatural history of the species in question as well as explain the rationale for certain conclusions regarding names. Figures and Color Descriptions. The color descriptions and illus- trations are based on fresh alcoholic specimens in most cases. Well- preserved specimens of Trochosa in which the hairs have not been rubbed off are very similar to the living spiders and were utilized where possible. The differences in live and freshly preserved lycosids is produced by shrinkage in alcohol, which disrupts the abdominal color pattern; wetting, which makes the specimen darker than in life; and rubbing off of appressed hairs which make up some of the color pattern. Where discrepancies in color between live and pre- served specimens have been observed, they are noted. Color descriptions and illustrations were made under low power (16X) of a dissecting microscope, with the spider illuminated by a microscope lamp. Where variation is great, the range of color pat- terns representative of the greatest number of specimens is des- cribed. A given specimen may not fit the general description in all details.
For each species a dorsal view of the female was drawn, with an additional drawing of T. terricola to indicate the range of variation. The dorsal color pattern is one of the distinctive features of the



================================================================================

19791 Brady - Spider Genus Trochosa 173
genus Trochosa. At least two drawings of the female genitalia were made for each species: a ventral external view of the epigynum after all the hair had been removed (often revealing some internal struc- ture through the integument) and a dorsal view with the separated genitalia submerged in clove oil for clearing. The female genitalia of all species are drawn to the same scale. Two views of the male palpus were drawn for each species: a ventral view and a retrolateral view. The left palpus of the male was drawn after gentle removal of hair to reveal the palpal sclerites. All palpi are drawn to the same scale. The female genitalia and the male palpus are classically used in identifying spider species and they are of considerable importance in Trochosa for that purpose.
Measurements. All measurements listed are in millimeters. Two net micrometers (0.5mm, 1 .Omm) were used in an ocular (1 6X) with a combination of low (IX) and high (4X) power objectives for mak- ing measurements. The higher power combination was used in measuring the eye rows and was determined to be accurate to 0.2 units of the micrometer grid or 0.025mm. The lower power combi- nation was used to measure the body dimensions and leg lengths and was determined to be acccurate to 0.2 units of the micrometer grid or 0.lmm. A measurement when retaken always read within two units of the original measurement with either of the micrometer grids, e.g., an original measurement of 6.5 micrometer units when retaken would read 6.3-6.7 units. In all cases the greatest dimension of the structure was recorded, e.g., patellea-tibia length was mea- sured as the greatest distance from a line tangent to the most prox- imal part of the patella to a line tangent to the most distal part of the tibia.
The segments of leg I were measured from the prolateral aspect, as was patella-tibia 11. The segments of leg IV were measured from the retrolateral aspect, as was patella-tibia 111. This method was found to be accurate and resulted in fewer broken legs than others that were tried. Total body length was estimated by measuring the abdomen and adding this figure to carapace length. Although the anterior end of the abdomen tends to overlie part of the cephalo- thorax, the abdomen usually shrinks in alcohol, reducing its size. Measurements of total body length in this fashion can be repro- duced more accurately, and since this dimension is highly variable, its primary function is for general recognition, not definition of the species.




================================================================================

174 Psyche [June-September
A set of 10 specimens of each sex was measured to give some idea of the range of variability within a species. A series of 19 different measurements was made of selected specimens of all species. Since eastern and western populations of Trochosa terricola differ in the number of posterior cheliceral teeth (Map 1) and in color and were described as different species, it seemed best to treat them separately for comparison. Six additional measurements of T. terricola epi- gyna, used by Locket and Millidge (195 1) to separate female speci- mens of European Trochosa, were also made to compare North American populations of terricola with European populations. The range and mean for the more significant measurements are recorded for each species. The measurements should prove useful not only to identify certain species of North American Trochosa, but to help distinguish this genus from others as the study progresses, Prelimi- nary measurements of other lycosids indicate that both the eye arrangement and ratio of leg length to carapace width or length are useful in distinguishing genera.
Diagnosis. The species under investigation is compared to its closest relative(s) and differences that distinguish them are noted. Natural History. In discussing methods (in a broad sense) it is appropriate to emphasize the importance of routine observations in the field. It is not the province of the systematist to explore and record detailed elements of the ecology and behavior of each species he studies, nor is it practicable from the standpoint of time, but it behoves him to note the habitat where certain species are found and any peculiar behavioral traits associated with the species. This kind of information is often as valuable to the systematist as that con- cerning morphological features and should be incorporated into decisions about species relationships.
Distribution. The geographic range of the species is given. Records. Includes only those specimens examined. Collecting localities for Canada are listed by city or town and separated by a semicolon. Multiple records for the United States are listed by county and separated by a semicolon. Collection records at the periphery of the species range are given in detail. The lower case "0" represents immature specimens.
This study was made possible by the loan of large numbers of specimens from the Museum of Comparative Zoology, Cambridge,



================================================================================

19791 Brady - Spider Genus Trochosa 175
Massachusetts, the American Museum of Natural History, New York City, and the Canadian National Collection, Ottawa, Canada. I wish to thank sincerely the curators of these collections, Dr. H. W. Levi, Dr. N. I. Platnick, and Dr. C. D. Dondale respectively, for the use of these materials. The study of type specimens on loan from the Museum of Comparative Zoology and the American Museum was an essential part of this investigation. Special thanks are extended to Dr. C. D. Dondale who kindly consented to review the manuscript and offered constructive criti- cism and friendly advice. Thanks also go to Dr. J. Reiskind who supplied important specimens from the University of Florida collec- tion. Dr. Torbjorn Kronestedt sent critical European specimens for examination and supplied information about the syntypes of Tro- chosa terricola Thorell. I am grateful to Mr. F. R. Wanless for sending specimens of Trochosa avara Keyserling from the L. Koch collection maintained in the British Museum (Natural History). Finally a word of appreciation and recognition is given to Dr. W. J. Gertsch, Dr. H. K. Wallace, the late Dr. A. M. Chickering, and the late Mr. W. Ivie for their efforts in collecting many of the specimens examined.
Initial support was provided during the summers of 1975 and 1976 by the Andrew W, Mellon Foundation under the program for faculty development at Hope College. National Science Foundation grant DEB-7803561 helped defray expenses of this investigation. Key to Females
la.
Posterior margin of cheliceral fang furrow with three teeth . . ................................................... 2 lb.
Posterior margin of cheliceral fang furrow with two teeth terricola
............................................ 2a.
Longitudinal piece of median septum of epigynum narrow, with lateral ends of transverse piece directed anteriad (Figs. 8, 9, 18, 20, 21, 23, 25, 27) ........................... 3 2b. Longitudinal piece of median septum of epigynum broad, with transverse piece straight (Figs. 10, 13, 14, 16) . . terricola 3a. Longitudinal piece of median septum with blunt, posterior median process and with lateral ends of transverse piece extending only slightly anteriad (Figs. 20, 21). Eastern United States (Map 2) ................................ avara



================================================================================

Psyche [June-September
Longitudinal piece of median septum without blunt, posterior median process and with lateral ends of transverse piece extending considerably anteriad (Figs. 8, 9, 18, 23, 25, 27) 4 Color pattern of carapace with two dark, elongate spots or short dashes within light, broad median stripe (Figs. 3,5,6) 5 Color pattern of carapace without dark spots or dashes within light, broad median stripe (Fig. 4). Western United States (Map 2) .................................... gosiuta Width of transverse piece of epigynum less than twice length ......
of longitudinal piece (Figs. 18, 23, 25) shenandoa
Width of transverse piece of epigynum more than three times length of longitudinal piece (Figs. 8,9). Primarily restricted to peninsular Florida and adjacent regions (Map 3) parthenus Key to Males
Posterior margin of cheliceral fang furrow with three teeth ................................................... 2 Posterior margin of cheliceral fang furrow with two teeth terricola
............................................ Embolus of palpus long and thin with tip curled to form characteristic loop or "pig-tail" (Figs. 28-3 1) ... terricola Embolus of palpus with broad flattened subterminal area and short, thinner tip forming hook but not loop (Figs. 32-37, 39, 40, 42, 43, 45, 46) ................................. 3 Total body length 5.7-7.6 mm. Primarily restricted to penin- sular Florida and adjacent regions (Map 3) ... parthenus Total body length 7.5-8.4 mm. Occurring outside peninsular Florida ........................................... 4 Palea of palpus with prominent distal knob (Figs. 34-37, 39, 40, 42, 43) and proximal pair of retrolateral macrosetae of .............. tibia I stout and elongate (Figs. 38, 41) 5 Palea of palpus without prominent distal knob (Figs. 45, 46) and proximal pair of retrolateral ventral macrosetae of tibia I not as stout or elongate (Fig. 44). Western United States (Map 2) .......................................... gosiuta Median apophysis of palpus greatly enlarged and directed ventrad (Figs. 36, 37, 39, 40). Proximal retrolateral ventral macroseta of tibia I not extending more than one-half distance ...
along shaft of median retrolateral macroseta (Fig. 38) avara
...............................................



================================================================================

1 9791 Brady - Spider Genus Trochosa 177 5b. Median apophysis of palpus not as large (Figs. 34, 35,42,43). Proximal retrolateral ventral macroseta of tibia I extending more than one-half distance along shaft of median retrolateral macroseta (Fig. 4 1) . . . . . . . . . . . . . . . . . . . . . . . shenandoa Trochosa terricola Thorell
Figures 1, 2, 10-16, 28-31. Map. I. Table 1. Lycosa trabilis:
C. L. Koch 1836: heft 134, pis. 19, 20; 1840: 410; 1847: 229. Not Lycosa trabalis Clerck according to Thorell 1856. Trochosa trabalis: C. L. Koch 1848: 141. Not Lycosa trabalis Clerck according to Thorell 1856.
Lycosa agretyca: Blackwall 1842: 407. Not Lycosa agretyca Walckenaer according to Pickard-Cambridge 1874.
Trochosa terricola: Thorell 1856: 171. Syntypes (2(5(5:32$) from Uppsala, Sweden, in the Natural History Museum, Stockholm, Sweden, not examined, but see below. Pickard-Cambridge 1874: 332. Bonnet 1959: 4713. Lycosa terricola: Westring 1861: 529.
Tarentula terricola: Collett 1875: 255.
Trochosina terricola: Simon 1885: 10.
Lycosapratensis Emerton, 1885: 483, pi. 46, figs. 4,4a, 4b, $3. Two female syntypes from Salem, Essex Co., Massachusetts, in the Museum of Comparative Zoology, examined. Emerton 1894: 422, pi. 3, fig. 4,$; 1902: 69, figs. 168-170,$; 191 3: 156; 1914: 118; 1920: 328; 1921: 108; 1924: 123, 124; 1928: 46; 1930: 168. Marx 1890: 563. Banks 1892: 64; 1895: 91; 1900: 483; 1907: 57; 1910: 57; 1916a: 71; 1916b: 80. Harrington 1897: 191. Slosson 1898: 248. Britcher 1903: 191. Ruthven 1906: 101. Bryant 1908: 85. Chamberlin 1908: 225, 261, pi. 21, fig. 3, Q. Petrunkevitch 1911: 565. Comstock 1913: 638, fig. 720a, 9; 1940: 649, fig. 720b, $ Barrows 1918: 3 14.