The Systematics and Distribution of Crayfishes in California'

THE SYSTEMATICS AND DISTRIBUTION OF CRAYFISHES IN CALIFORNIA' J. A. RIEGEL Department of Zoology University of California, Davis INTRODUCTION C rayfishes are interesting and im portant m em bers of C alifornia's freshwater fauna. They are an excellent food, have value as gam e fish forage, and are used by fisherm en as bait for gam e fish. On the negative side, the burrow ing habits of som e species at tim es m ake them a m enace to irrigation structures in agricultural areas. Because no comprehensive account has heretofore been published on the crayfishes in California, with the exception of a popular report by B onnot (1930), it is believed this paper w ill be of value to both the scientist and layman. Brief descriptions of species of California crayfishes occur in early expedition reports, and a few are mentioned in monographs on various (Hagen, 1871; and Faxon, (Holmes, 1900). crustacean groups, primarily the 1889, 1895, 1898, and 1914), and the marine A bout the m iddle of the 19th century, crayfishes w ere collected and described by naturalists accom panying the Pacific explorations of the <ul style="display: flex;"><li style="flex:1">S. Exploring Expeditions. In 1852, </li><li style="flex:1">Boundary Commission and the </li></ul>In th e sa m e y e a r, Pacifastacus gambeli. Charles G-irard described Jam es D ana established In 1859, W illiam Stim pson P. <ul style="display: flex;"><li style="flex:1">and P . </li><li style="flex:1">P. trowbridgi, P. nigrescens, </li></ul>described At the time of these early explorations, only two species were found However, in the M useum of <ul style="display: flex;"><li style="flex:1">and P. </li><li style="flex:1">Pacifastacus nigrescens </li></ul>in California, P. gambeli Faxon (1885) referred to a specim en of Com parative Zoology, H arvard, w hich w as included w ith a group of specim ens from Santa Barbara, California ; but as no other specim en of that species had been found in C alifornia, he doubted the validity of the record. G irard) of the of the Continental introduced into the S tate and are thriving. has been introduced into California from Ore- (Procambarus clarki H agen) and Orconectes virilis ( subfamily Cambarinae, native to North America Divide, have since Pacifastacus is now widely distributed throughout clarki Procambarus clarki gon and with is the only crayfish Mountains. and proposed the generic the central part of the State. know n to inhabit the w aters south of the Astacus In 1950, B ott revised the genus native to N orth A m erica w est of Pacifastacus for the name 1Submitted for publication September, 1958. <ul style="display: flex;"><li style="flex:1">Zoology, State College of W ashington, Pullm an, </li><li style="flex:1">Present address: Department </li></ul>( 29 ) 30 CALIFORNIA FISH AND GAME the Continental Divide. His proposal is accepted in this paper. A further revision of Pacifastacus is herein presented, in which trowbridgi is shown to be synonymous with P. leniusculus. Descriptions and figures of all species of crayfishes known or reported from California are included. M aterials and distribution records upon which this paper is based were obtained by collections throughout California, by circularizing appropriate institutions in the State, and from the available literature. SYSTEMATICS Five species of crayfishes representing two subfamilies and three genera are now known to occur in California. These are Pacifastacus leniusculus (Dana), Pacifastacus (Stimpson), and nigrescens (Stimpson) of the subfamily Astacinae ; Procam- <ul style="display: flex;"><li style="flex:1">barus clarki (Girard) and </li><li style="flex:1">Orconectes virilis ( </li></ul>Hagen) of the subfamily though generally assumed to be a variation of P. lenius- and P. nigres- be considered as native to California ; the others were pre- Cambarinae. Pacifastacus trowbridgi, a distinct species, is here considered to be culus. Of the above-named species, only P. cens may sumably introduced. <ul style="display: flex;"><li style="flex:1">Bott (1950) proposed the generic name </li><li style="flex:1">for the </li></ul>of western North America. This proposal seems valid considering certain morphological differences between the European and North American species. In discussing the new name, he remarked that Paci- confined to the coastal region of North America between fastacus is the Pacific Ocean and the Rocky Mountains. Similar characteristics in the gonopods of the male and other morphological characteristics indicate a direct relationship of Pacifastacus with Bott's two European <ul style="display: flex;"><li style="flex:1">Austropotamobius. </li><li style="flex:1">genera, Astacus and </li></ul>Hobbs (1941), in a generic revision of the subfamily Cambarinae, <ul style="display: flex;"><li style="flex:1">Cam barus into five genera and added a new monotypic genus to </li><li style="flex:1">split </li></ul>Cambarus, make six, namely, Procambarus, Orconectes, Troglocambarus (the new monotypic genus), and Paracambarus. Of Procambarus and Orconectes <ul style="display: flex;"><li style="flex:1">these, only </li><li style="flex:1">are represented in California. </li></ul>Systematic Revision of Since species of cambarines are now differentiated chiefly on the morphology of the male first pleopod, and since the sexual apparatus is generally a conservative system atic character, the writer has attempted to distinguish members of Pacifastacus on that basis. Comparison of the sexual appendages of the previously determined species shows four of the five original species are valid. These are Pacifastacus <ul style="display: flex;"><li style="flex:1">leniusculus, P. </li><li style="flex:1">and P. nigrescens </li></ul>(see remarks P. gambeli, after the species description). The fifth, P. trowbridgi, is only a variant of P. leniusculus, as will be shown. It is difficult, however, to differentiate species of Pacifastacus by the sexual appendages alone, as those structures look so nearly alike. Unless an investigator is quite familiar with the peculiarities exhibited in each, there is considerable possibility of error. Further, individuals of the same species, but of different age (size) groups, vary slightly in the conformation of the sexual appendages. No dimorphism can be recognized in the gonopods, as is seen so strikingly in the subfamily Cambarinae. 31 CRAYFISH ES IN CALIFO RN IA Procambarus clarki X FIG U R E 1. A . B. Orconectes XPacifastacus trowbridgi male cotype X 2. C. Rostral area of cotype (left) and P. trowbridgi D. D orsal view of left gonopod of leniusculus (right) X 3. cotype (left) and P. trowbridgi E. V entral view of left gonopod of leniusculus (right) X 3. Illustration of variation in spines in three m ale acum en length and posterior pastorbital leniusculus (from a single collection). <ul style="display: flex;"><li style="flex:1">C. Clinton. </li><li style="flex:1">by G eorge </li></ul>32 AND GAM E Differences in the sexual appendages of P. trowbridgi ( leniusculus and Figure 1 D , E ) are indistinguishable, indicating the probability that they are not separate species. C om parison of other characters that have been used in differentiating these tw o species clearly confirms the suspicion that P. trowbridgi is but a junior synonym of P. leniusculus. P. leniusculus has been characterized as having well-developed posterior postorbital spines and an acum en exceeding in length the distance between the lateral spines of the rostrum , while typical P . acumen not exceeding in length the distance between the lateral spines of the rostrum (Figure 1 F-H ). In a large series of has obsolete posterior postorbital spines and an P. leniusculus, posterior postorbital spines vary from the low tubercles characteristic of P. of <ul style="display: flex;"><li style="flex:1">(</li><li style="flex:1">Figure 1 F) to the well-developed spines characteristic </li></ul>P. leniusculus (Figure 1 II). The rostral acumen varies from a relatively short one characteristic of P . trowbridgi (Figure 1 F ) to a relatively long one characteristic of P. leniusculus (F igure 1 II). T he apparent lack of correlation betw een the presence or absence of the posterior postorbital spines and the length of the rostral acum en is illustrated in Figure 1 G . T herefore, "typical" P. and P. trowbridgi merely represent extremes in variation with respect to these tw o characters ; and this, together w ith the sim ilarity of their sexual <ul style="display: flex;"><li style="flex:1">be considered a syno- </li><li style="flex:1">appendages, clearly dictates that P . </li></ul>nym of P. <ul style="display: flex;"><li style="flex:1">W ith the elimination of P . </li><li style="flex:1">as a valid species, determina- </li></ul>species can readily be m ade on a com bination of tion of Pacifastacus structural characters m ore distinct than the sexual appendage. GLOSSARY OF TERMS USED IN CRAYFISH SYSTEMATICS <ul style="display: flex;"><li style="flex:1">A N N U LU S V EN TR A LIS: B lind pouch betw een the </li><li style="flex:1">of the fifth pair of w alk- </li></ul><ul style="display: flex;"><li style="flex:1">ing legs in fem ale </li><li style="flex:1">fo r th e sto rag e o f sp erm s u n til th e tim e o f </li></ul>extrusion of the eggs. BA SIS: Second segm ent of a w alking leg. C A R PU S: Fifth segm ent of a w alking leg. COXA: First or basal segm ent of a D A CTY LU S: EPISTO M E: GONOPOD: Seventh segm ent of a w alking leg. R egion of the ventral w all of the head just anterior to First and second abdom inal appendages of m ale for sperm transfer. ISC H IU M : M ER U S: Third segm ent of a w alking leg. Fourth segm ent of a w alking leg. P E R E IO P O D : PL E O PO D : A ppendage (leg) of the thorax. (leg) of the abdom en. <ul style="display: flex;"><li style="flex:1">PL E U R O B R A N C H : </li><li style="flex:1">G ills arising from the m edial w all of the gill </li></ul><ul style="display: flex;"><li style="flex:1">PR O PO PO D : </li><li style="flex:1">Sixth segm ent of a w alking leg. </li></ul>Key to the California Crayfishes u se d in sy ste m a tic s a re sh o w n in 2defined in the glossary. <ul style="display: flex;"><li style="flex:1">1</li><li style="flex:1">L ast thoracic segm ent lacking </li><li style="flex:1">g re e n g la n d o rific e a t o r n e a r </li></ul><ul style="display: flex;"><li style="flex:1">apex of </li><li style="flex:1">ischium of one or m ore pairs of thoracic legs of m ale hooked </li></ul>(subfam ily : O roonectes or Procambarus, g en era nativ e to N o rth A m erica east of continental divide) - - - - - - - - - - - - - - - - - 33 CRAYFISHES IN CALIFORNIA segm ent bearing a pleurobranch ; green gland orifice at or near 1 ' Last base of (subfam ily none of thoracic legs of m ale <ul style="display: flex;"><li style="flex:1">3</li><li style="flex:1">- - - - - - - - - - - - - - </li></ul>only native genus of w estern N orth A m erica) hooked ; epistome of third and fourth pairs of thoracic legs of 2truncate, carapace markedly tuberculate (Figure 1 A and Figure 4) (G irard). Procambarus clarki of third pair of thoracic legs of male hooked ; epistome truncate with 2' Ischium on anterior border, carapace slightly granulate laterally H agen). medium low (Orconectes virilis <ul style="display: flex;"><li style="flex:1">Figure 1B and Figure 5) - - - - - - - - - - - - - - - - - </li><li style="flex:1">(</li></ul>45<ul style="display: flex;"><li style="flex:1">- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - </li><li style="flex:1">3' M argins of rostrum smooth </li></ul><ul style="display: flex;"><li style="flex:1">3</li><li style="flex:1">M argins of rostrum denticulate - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - </li></ul>ridge w ith or w ithout posterior spine or tubercle; w hite or blue- 4 Postorbital of cheliped (Figure 3 A (D a n a ) green patch across junction of dactylus and and Figure 6) - - - - - - - - - - - - - - - - - - - - - - - - Pacifastacus 4' Postorbital ridge never w ith posterior spine or tubercle ; no w hite or bluegreen patch as above (Figure 3 B and Figure 7) 5 C helae w ith one or tw o patches of soft setae on outer face (Figure 3 C and <ul style="display: flex;"><li style="flex:1">Girard) </li><li style="flex:1">(</li><li style="flex:1">Figure </li><li style="flex:1">- - - - - - - - - - - - - - - - - - - - - - - - - - - - Pacifastacus gambeli </li></ul>5' Chelae naked on outer face (Figure 3D and Figure 9) Pacifastacus nigrescens (Stimpson). Genus PROCAMBARUS Ortman Procambarus Carnegie Mus. Ann., vol. 3, no. 3, p. 437. 1905. "First pleopod of first form m ale term inating in from tw o to five distinct parts which may be truncate, platelike, or spiniform. Shoulders present on cephalic surface of distal third. If the pleopod terminates in present on the of the third or of the third and fourth pereiopods in the m ale. only tw o parts this shoulder is alw ays present. inner <ul style="display: flex;"><li style="flex:1">teeth along </li><li style="flex:1">Third maxillipedes of normal size bearing a </li></ul>margins of the ischiopod." Hobbs, 1942. Procambarus clarki (Girard) clarki Girard, 1852. Acad. Nat. Sci. Phila., Proc., vol. 6, p. 91. carapace and chelae m arkedly tuberculate or granu- "M ale form late; hooks on third and fourth legs of m ale ; areola very narrow or obliterated; rostrum edges ridgelike and greatly excavated, sides converging to point of lateral spines; very prom inent spine on inner edge o r spines on ventral surface of m erus of chelae ; first abdom inal legs of teeth" Faxon, 1885. A nnulus ventralis of fem ale oval with a sigm oid groove across the center, with two at the anterior border. differs from male form I in having the three points on <ul style="display: flex;"><li style="flex:1">of chelae ; double row of </li><li style="flex:1">and ventral surface of </li></ul>m ale truncate w ith three short M a le form II: the end of the first pleopod less distinct. "Som ew here betw een San A ntonio and El Paso Type locality: del Norte, Texas" Faxon, (1898). <ul style="display: flex;"><li style="flex:1">C ontra C osta C ounty, D iablo C reek </li><li style="flex:1">m ile </li></ul>m iles w est C avell; Fresno miles southeast Mendota; Imperial County, southwest Concord, Diablo Creek County, cattail pond <ul style="display: flex;"><li style="flex:1">Unless otherwise stated, all localities </li><li style="flex:1">in </li></ul>34 A N D ANTENNA CHEL A ANTENNULE <ul style="display: flex;"><li style="flex:1">SCALE </li><li style="flex:1">ANTENNAL </li></ul>ACUMEN ROSTRUM ANTERIOR SPINE POSTORBITAL RIDGE POSTERIOR SPINE CERVICAL SPINE - CERVICAL GROOVE AREOLA UROPOD TELSON LATERAL SPINE <ul style="display: flex;"><li style="flex:1">FIGURE 2. </li><li style="flex:1">Dorsal view of a crayfish w:th characters labeled that are important systematically. </li></ul>Colorado canal 10 m iles south B akersfield; Los A ngeles <ul style="display: flex;"><li style="flex:1">opposite </li><li style="flex:1">K ern C ounty, B akersfield, </li></ul>B alboa <ul style="display: flex;"><li style="flex:1">n e a r </li><li style="flex:1">P u d d in g sto n e </li><li style="flex:1">five m iles w est P om ona, </li></ul>Puente C reek near W hittier; M adera C ounty, irrigation ditch near Roadside Slough 12 m iles south <ul style="display: flex;"><li style="flex:1">o n U . S . </li><li style="flex:1">9 9 ; </li><li style="flex:1">C o u n ty , T rem b lad ero S lo u g h </li></ul><ul style="display: flex;"><li style="flex:1">north of </li><li style="flex:1">R iver m outh; O range C ounty, C osta M esa; R iver- </li></ul>side C ounty, C a n a l; S a c ra m e n to C o u n ty , D ry C reek below R oseville, slough parallel A m erican R iver three m iles northw est Sacram ento; San B ernardino C ounty, L ake A rrow head n ear E m erald B ay , S an ta A n a R iv er n ear A rlin g to n ; S an D ieg o 35 CRAYFISHES IN CALIFORNIA (Dana) X Y2. leniusculus <ul style="display: flex;"><li style="flex:1">A . Pacifastacus </li><li style="flex:1">FIGURE 3. </li></ul>XPacifastacus klamathensis B. C. D. gambeli (Girard) X Pacifastacus nigrescens (Stimpson) Clinton X George C. Photographs by <ul style="display: flex;"><li style="flex:1">A</li><li style="flex:1">I A N D </li></ul>FIGURE 4. P rocam barus clarki (Girard). a. b. right chela. c. gonopod of 1st form male, dorsal view. male, ventral view. d. gonopod of 1st form male, ventral view. e. gonopod of 2nd form f. gonopod of 2nd form male, dorsal view. g. epistome. annulus ventralis of female. h. anterior process of 37 County, Spook Canyon near Escondido, small creek near Carlsbad, C RA Y FISH E S IN C A LIFO RN IA <ul style="display: flex;"><li style="flex:1">Lake </li><li style="flex:1">San Dieguito River three miles below Lake </li></ul><ul style="display: flex;"><li style="flex:1">395 bridge, Doane Lake tributary to San Luis </li><li style="flex:1">near U. S. </li></ul>Rey River ; San Joaquin County, Mokelumne River near irrigation ditch one mile north Stockton ; Santa Barbara County, Ranch near Santa Santa Ynez River at Los Prietos, ditch Barbara ; Sonoma County, Russian River at Mirabel Park ; Stanislaus County, Tuolumne River three miles above junction with San Joaquin River. seems well adapted to its new environ- Remarks: Procambarus clarki ment in central and southern California. It prefers sloughs where the water is relatively warm and vegetation plentiful, but it is often found in large streams. It commonly is found in rice fields and irrigation ditches in the Central Valley, where it is regarded as a pest because its burrowing causes considerable damage to those structures. In southern California, where streams commonly run dry during the summer, it is able to survive by burrowing to the water level. Procambarus Preliminary observations indicate that in California clarki breeds in late summer and early fall; the offspring hatch early in <ul style="display: flex;"><li style="flex:1">undergoes a moult shortly before the breed- </li><li style="flex:1">the fall. The male </li></ul>P. clarki ing season by which it changes from second to first form, the latter being the sexually mature form. Whether first form males can return again to second form is not known. Second form males predominate in collections made before or after the breeding season. These observations concur with the natural history of (Penn, 1943). in its native Louisiana P. clarki Genus ORCONECTES Cope Orconectes Cope, 1872. Amer. Nat., vol. 6, p. 419. "First pleopod of first form male terminating in two distinct parts, both parts ending in straight, gently curved, short, or long spines (occasionally the central projection, 'outer part,' terminates in a bladelike process). Never is a strongly developed shoulder present on the cephalic margin near the tip of the appendage. The central projection is cornious, while the mesial process is usually much softer. In the male, hooks are generally present on the ischiopod of the third and fourth pereiopods. Third maxillipeds of normal size with a row of teeth along the inner margin of the ischiopod." Hobbs, 1942. Orconectes virilis (Hagen) Cambarus virilis Hagen, 1871. Harvard Mus. Comp. Zool. Illus. Cat., no. 3, p. 63. M ale form I:

The Systematics and Distribution of Crayfishes in California'

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