XI ^ NovitatesXT AMERICAN MUSEU M PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET NEW YORK, N.Y. 10024 U.S.A. NUMBER 2634 OCTOBER 11, 1977 RICHARD C. BRUSCA AND BARRY R. WALLERSTEIN The Marine Isopod Crustacea of the Gulf of California. I. Family Idoteidae AMERICAN MUSEUM NovitatesAT PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79 TH STREET, NEW YORK, NY. 10024 Number 2634, pp. 1.-17, figs. 1-7 October 11, 19 77 The Marine Isopod Crustacea of the Gulf of California. I. Family Idoteidae RICHARD C. BRUSCA1 AND BARRY R. WALLERSTEIN2 ABSTRACT The valviferan isopods of the Gulf of Cali­ genera and species having evolved in the lower fornia are reviewed, including eight species in latitudes (e.g., Eusymmerus, Colidotea, and some four genera. One rediscovered species (Eusym- species of Erichsonella). Members of this family, merus antennatus) and two new species (Coli- in the tropical and subtropical east Pacific, are dotea findleyi and Erichsonella cortezi) are fully generally found in association with littoral and described. Two of the Gulf idoteids appear to be shallow-water algae, especially species of Sar- of subtropical or tropical origin (Eusymmerus gassum. Four species of Idotea are extremely antennatus and Colidotea findleyi), whereas the wide-ranging forms, suggesting that members of others appear to be cold or warm temperate de­ this genus may be considerably more euryther- rived species (Erichsonella cortezi, Idotea acu- mal than previously suspected. Idotea wosne­ leata, L urotoma, I. stenops, I. resecata, and /. senskii and /. resecata range from the Gulf of wosnesenskii). These findings suggest, as other California to Alaska; I. stenops ranges from Baja distributional data have, that the family California (or possibly the Gulf of California) to Idoteidae is composed largely of cool to warm Oregon; and /. urotoma ranges from the Gulf of temperate-centered taxa, with few modern California to Puget Sound. INTRODUCTION Over the past six years the senior author has (summarized and discussed by Steinbeck and accumulated a large collection of marine isopods Ricketts, 1941; Fraser, 1943; Goldman, 1951; from the coasts of Sonora, Sinaloa and Baja Cali­ Rodin and Groves, 1959; and others), few publi­ fornia. In addition the authors had available the cations on marine isopods have resulted from idoteid isopod material of the Allan Hancock these efforts. The present paper represents the Foundation, the California Academy of Sciences, first of a series intended to describe the marine and the National Museum of Natural History, isopod fauna of that region. Keys to the higher Smithsonian Institution. taxa of this group may be found in Brusca (1973 Although several significant biological expedi­ and In press). Three recent publications discuss tions have been made into the Gulf of California the idoteid isopod fauna of California (Menzies 'Curator of Crustacea, Allan Hancock Foundation. 2Assistant Curator, Allan Hancock Foundation. Copyright © The American Museum of Natural History 1977 ISSN 0003-0082 /Price SI.25 2 AMERICAN MUSEUM NOVITATES NO. 2634 and Waidzunas, 1948; Menzies, 1950; Miller and antenna 2 multiarticulate or reduced to 1 Lee, 1970). Idoteid terminology in this paper fol­ article 6 lows that of Menzies (1950), and all synonymies 2. Maxillipedal palp of 4 articles (fig. 1A) of species of Idotea are subsequent to that publi­ Idotea (Idotea) urotoma cation. Zoogeographic provinces are based on Maxillipedal palp of 5 articles 3 Briggs (1974) and Brusca (1975 and In press). 3. Eyes transversely (dorsoventrally) elongate; apex of frontal process with median notch; The authors take pleasure in expressing their maxilliped with 1, 2, or 3 coupling hooks gratitude to Dr. Dorothy E. Bliss (AMNH) and to (fig. IE) Idotea (Pentidotea) stenops Dr. Bernard C. Abbott (AHF). We are indebted Eyes oval or reniform; apex of frontal process to our colleague Miss Janet Haig, for her con­ entire or slightly concave; maxilliped with tinual assistance during the preparation of this 1 coupling hook 4 paper. In addition, appreciation is extended to 4. Posterior border of pleotelson strongly con­ Drs. Thomas E. Bowman (National Museum of cave; frontal process narrow and pointed, Natural History, Smithsonian Institution) and extended beyond frontal lamina 1 (fig. IB) Fahmida Rafi (National Museum of Canada) for Idotea (Pentidotea) resecata Posterior border of pleotelson convex, with critically reviewing the manuscript. Miss Mary small median lobe; frontal process blunt or Ellen Pippin and her staff greatly assisted us with widely angular, not extended beyond mar­ the literature search and Mr. Richard (Paco) gin of frontal lamina 1 5 Winn prepared the illustrations of the Idotea spe­ 5. Pleonite 1 with acute lateral borders; eyes cies (fig. 1). Abbreviations of institutions are as reniform; pereopod 7 with distinct tufts of follows: AMNH (the American Museum of Natu­ setae on articles 4-6 (fig. 1C) ral History); AHF (Allan Hancock Foundation); Idotea (Pentidotea) wosnesenskii NMNH (National Museum of Natural History, Pleonite 1 without acute lateral borders; eyes Smithsonian Institution). circular; pereopod 7 without tufts of setae This is contribution No. 362 of the Allan Han­ on articles 4-6 (fig. ID) Idotea (Pentidotea) aculeata cock Foundation. This research was supported, 6. Flagellum of antenna 2 multiarticulate (fig. in part, by grants from Sigma Xi, the National 2H) Colidotea findleyi, new species Science Foundation (Alpha Helix Research Pro­ Flagellum of antenna 2 of a single article ... 7 gram), and the University of Southern California 7. Lateral margins of pleon smooth and gently (22-1813-9790). convex; pleon with anterior segment indi­ cated by a suture line (figs. 4,5) FAMILY IDOTEIDAE DANA (BY MIERS, 1881) Eusymmerus antennatus Lateral margins of pleon expanded posteri­ Valviferan isopods with body generally dorso- orly; pleon without suture lines (figs. 6,7) ventrally depressed; first pair of antennae usually Erichsonella cortezi, new species shorter than second; flagellum of antenna 1 usu­ ally of 1 article; maxillipedal palp of 3-5 articles; GENUS IDOTEA FABRICIUS, 1799 pleon composed of 1-3 free segments; uropoda usually uniramous. Eyes lateral; maxillipedal palp composed of 4-5 articles; pleon composed of two segments SUBFAMILY IDOTEINAE DANA, 1853 plus the pleotelson; pleonal segment 3 indicated by partial suture lines on lateral margins of Uropods uniramous (except in Cleantis); all pleotelson. pereopods similar, never subchelate; head not lat­ erally expanded. SUBGENUS IDOTEA Maxillipedal palp composed of 4 articles. KEY TO THE SPECIES OF IDOTEIDAE KNOWN FROM THE GULF OF CALIFORNIA Idotea (Idotea) urotoma Stimpson, 1864 1. Pleon composed of 3 distinct segments; flagel­ Figure 1A lum of antenna 2 multiarticulate 2 Pleon composed of one segment; flagellum of Synonymy. Ricketts, Calvin and Hedgpeth, 1977 BRUSCA AND WALLERSTEIN: CRUSTACEA 3 FIG. 1. Idotea of the Gulf of California. A. Idotea {Idotea) urotoma. B. Idotea {Pentidotea) resecata. C. Idotea {Pentidotea) wosnesenskii. D. Idotea {Pentidotea) aculeata. E. Idotea {Pentidotea) stenops. 1968, p. 243; Kozloff, 1974, p. 149; Miller, dorsal view. Lateral margins of cephalon converg­ 1975, pp. 289, 290, 305; Allen, 1976, p. 216. ing anteriorly. Eyes small, quadrangular. Maxil- Diagnosis. Supra-antennal line weakly bi- liped with one coupling hook; apical article of lobed medially. Frontal process elongate, apex palp without long setae on outer border. Poste­ blunt; frontal lamina 1 not exceeding length of rior border of pleotelson obtusely pointed; in fe­ frontal process, with produced sides and a deep males the posterolateral borders are usually not median concavity; frontal lamina 2 not visible in irregular, whereas in males the first half of each 4 AMERICAN MUSEUM NOVITATES NO. 2634 posterolateral border is slightly concave and the (base of which nearly covers median third of pos­ posteromedial part is convex and provided with a terior margin of pleotelson). distinct but minute median tooth. Conspicuous, Distribution and Remarks. This species was short, posteriorly projecting, posterolateral previously known to range from Dillon Beach angles formed on the pleotelson of some male (central California) to San Diego. We have ex­ specimens. amined specimens from outer Baja California Distribution and Remarks. Although formerly (Isla Cedros) and from Bahi'a La Paz in the lower known from Puget Sound to Ensenada (including Gulf of California. The specimens from La Paz the Channel Islands of California), we have ex­ were taken from intertidal sand flats with scat­ amined specimens from the entire west coast of tered rocks, algae, and coral heads. The water Baja California, as well as one collection contain­ temperature was 24.2°C. The specimens from ing numerous individuals from Bahi'a La Paz, in Isla Cedros were collected on algae-covered rocks the Gulf of California. We also have records from in the low intertidal region. Guadalupe Island. Like certain other members of the genus, /. urotoma now appears to be a highly Idotea (Pentidotea) stenops Benedict, 1898 eurythermal species, ranging through at least Figure IE three major marine zoogeographic provinces (by Briggs, 1974: Oregonian, Californian, and Cortez Synonymy. Miller, 1968, p. 21; Ricketts, Calvin provinces). Collections made in distinctly warm and Hedgpeth, 1968, pp. 132, 201, 489; water locales, such as Bahi'a La Paz, rule out the Schultz, 1969, p. 74;