102(3), 1989, pp. 613-619 JOHNGARTHI, N. SP. AND CANCER PORTERI (BELL) (CRUSTACEA, ): COMPARISONS AND HYPOTHESIS Alberto Carvacho Abstract. —, long mistaken for C. porteri, is described. It is known in the eastern Pacific from Isla Guadalupe, (29°N), south to Panama (7°N), on soft bottoms at depths exceeding 90 m. Differences from C. porteri are discussed with an emphasis on biological aspects: C. johngarthi shows an isometric growth of chelipeds in relation to carapace width, while in C. porteri a strong positive allometry is evident after the puberal molt. These two conditions may reflect different mating systems.

The species Cancer porteri, described by Bay of Panama in 210 to 286 fathoms, and Bell (1835) as C. longipes, was transferred from Peru to Chile in the Sublittoral." to the Platycarcinus, of Information gathered during almost 150 Cancer, by H. Milne-Edwards & Lucas years supported the idea that C. porteri was (1844), and given its present name by Rath- a eurybathic species with a wide geographic bun (1930). Nations (1975) included it in distribution. In fact, the case has been used the subgenus Cancer s.s. The holotype was as a paradigm of the peculiar tropical sub- collected in Valparaiso, Chile. Faxon (1895) mergence distribution pattern (Ekman 1953, recorded it from Panama Bay as deep as Garth 1961). 523 m (Albatross). These two eastern Pacific Careful study of several specimens re- localities, 33°S and 7°30'N, respectively, cently collected off Baja California Sur and were long considered as the geographic dis- the reexamination of virtually all specimens tributional limits of the species. identified with Cancer porteri from the Garth (1957) cited a continuous distri- Northern Hemisphere, along with several bution "from Callao, Peru to Valparaiso, specimens from Chile and Peru, leads to the Chile, 0-24 fms" and an extralimital record conclusion that they belong to two different from Panama. Nevertheless, he also includ- species. The morphological differences, ed in the list of examined material one male scarcely evident in young specimens, may collected by the Lund University Chile Ex- express divergence in their mating systems. pedition at Talcahuano (36°41'S), some 450 km south of Valparaiso. This latter record has been confirmed by Retamal & Yanez Cancer johngarthi, new species (1973). Garth (1961) recorded C. porteri Figs. 1, 3A, 4B from the coast of Sinaloa in the Gulf of Cancer longipes, Faxon, 1895:16; Rathbun, California, between 108 and 128 m, and 1930:199 (in part). mentioned that the species "may now be Cancer porteri Rathbun, 1930:199 (in part); reported as a bi-temperate species that Garth, 1957:50 (in part); 1961:122; Par- transgresses the tropics by submergence, ker, 1964:173; Chirichigno, 1970:45 (in being found in the Gulf of California, the part); Retamal & Yanez, 1973:12 (in part); 614 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON Nations, 1975:43 (in part); 1979:154, 156, long as wide. Adult males with second pleo- 178 (in part); Retamal, 1981:30 (in part). pod slightly overreaching second segment Carapace granulated, widely oval, very of thorax; first pleopod slightly overreach- convex and moderately areolated, with pro- ing third segment of thorax. tuberances on proto- and mesogastric re- Holotype.—In the collection of the Allan gions and on borders of epi- and meso- Hancock Foundation: male (carapace 14 cm branchial regions. Both mesobranchial wide, 8.7 cm long); Isla Guadalupe, Mexico; regions swollen and nearly meeting in me- 183 m; 15 Nov 1968, Velero IVsta. 12460- dian line. Frontal region convex. Front pro- 68; catalog number AHF 6815. jected and furnished with 3 teeth, median Material examined. — Paratypes: Isla slightly longer and narrower than others. In- Guadalupe, Mexico (29°N); 183 m, 15 Nov ner orbital tooth pointed and slightly short- 1968, Velero IV sta. 12460-68; 4 males, 1 er than frontal teeth. Anterolateral margin female, AHF 6816. Off Rio San Lorenzo, finely granulated, cut into 9 teeth; granu- Sinaloa, Mexico (24°15'N), 108-128 m; May lations enhanced posteriorly. Posterolateral 1959; 2 males, 6 females; AHF 5929. Off margin granulated and furnished with 2 Bahia Magdalena, B.C., Mexico (24°15'N), teeth, first small and second vestigial, some- 90-125 m; Jul 1987, 1 male, 3 females, CIB, times imperceptible. Pterygostomial region La Paz. Bahia de Panama; 384 m; Mar 1891; swollen and coarsely granulated towards Albatross sta. 3389; 1 female, MCZ, Har- outer edge. Whole carapace remarkably thin; vard University. epi- and subbranchial and pterygostomial Distribution.—Eastern Pacific from Isla regions may be easily flexed. Guadalupe, Mexico to Bahia de Panama. Buccal cavity well delimited anteriorly by Southern Gulf of California. projections of pterygostomial border, with Habitat. — Soft bottoms, 90-523 m. 2 strong vaults separated by a longitudinal Etymology. — Named in honor of Dr. John keel. S. Garth, Chief Curator Emeritus, Allan Maxillipeds granulated, with ischium and Hancock Foundation, University of South- merus widened distally. Merus with outer ern California, Los Angeles, California. face concave and a notch on distal half of inner margin where palp inserts. Comparison with Cancer porteri Chelipeds: fingers with tips and cutting The observations listed below and also edges dark, starting from proximal tooth. data for Figs. 3 and 4 resulted from the ex- Palm granulated, with 4 longitudinal cari- amination of 17 specimens of C. johngarthi nae on lower half of outer face. Propodus (carapace widths from 35 to 140 mm) and 2.7 times as long as wide in adult males. 43 specimens of C. porteri (c.w. 22.8 to 123 Carpus rough, with irregular granulated ca- mm). These latter came from Valparaiso, rinae and anterosuperior pyramidal tooth. Chile and from the following localities in Merus with subtriangular section and upper Peru: Bahia Independencia, Bahia San Juan, distal margin granulated. Isla San Lorenzo, Bahia San Nicolas, Ca- Walking legs long and slender, without llao, Isla Lobos de Afuera. spines or setae on proximal articles. Prop- 1. Chelipeds of adult males noticeably odus with scarce setae on distal end of lower stronger in C. porteri (Fig. 2a). As shown in margin. Dactylus with 4 symmetrical lon- Fig. 3B this allometric character is better gitudinal rows of setae and a deep groove expressed after the molt of puberty. along inner and outer faces, respectively. 2. Darkening in cutting edges of cheliped Abdomen in adult males with terminal fingers starts proximally in C. porteri but in segment narrowly rounded distally, lateral C. johngarthi it starts at first tooth. margins slightly concave and 1.1 times as 3. The most remarkable difference at any VOLUME 102, NUMBER 3 615

Fig. 1. Cancer johngarthi, male: a, Carapace, dorsal; b, Abdomen; c, Left cheliped; d, Second pleopod, distal end; e, First and second pleopods; f, First pleopod, distal end; g, Third maxilliped. 616 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON

» A j \

Fig. 2. Cancer porteri, male: a, Left cheliped; b, First pleopod, distal end; c, Abdomen. age is consistency of the carapace. C. john- garthi seems to be a paper shell species. The Hypothesis 4. Terminal segment in abdomen of males The genus Cancer originated in the north- with straight lateral margins in C. porteri eastern Pacific (Ekman 1953, Nations 1975, and slightly concave margins in C. john- 1979) and dispersed southward along the garthi (Figs, lb and 2c). west coast of the Americas. Four species 5. Pereopods proportionately longer and may be found in Peru and Chile; one of dactyli of walking legs longer in relation to these is C. porteri. This species, now sepa- propodi in C. johngarthi. rated from C. johngarthi, ranges from Isla 6. Width/length relation of carapace sig- Lobos de Afuera (6°57'S) to Talcahuano nificantly greater in C. johngarthi (Fig. 4). (36°41'S), covering most of the Peruvian- 7. As shown in Figs. If and 2b, apex of Chilean province (sensu Briggs 1974). The first male pleopods quite different in each morphological affinity and geographic dis- species. tribution of the two species suggest the ex- Habitat preferences of each species are istence of a common ancestor that trav- not sufficiently documented, but C. john- eled—perhaps in the —between garthi seems to prefer deeper waters; it has North and South America (Nations 1979). not been collected shallower than 90 m while Morphological divergence between C. C. porteri inhabits waters from the intertidal johngarthi and C. porteri may have resulted to more than 350 m (Yanez 1974). This from different mating systems. Orensanz & scheme agrees with the well known relation Gallucci (1988) explain some differences of Cancer and water temperature: species in among four sympatric species of Cancer, this genus usually live at latitudes greater such as dimorphic development of che- than those where the surface isotherm of lipeds, according to the models of polygyny 20°C is to be found (MacKay 1943, Nations established by Emlen & Oring (1977). Mat- 1979). At lower latitudes depth compen- ing systems of species with precocious de- sates thermal needs; such is the case of C. velopment of a strong cheliped may be in- borealis and C. irroratus in Florida, and es- terpreted as a case of resource defense pecially C. guezei in Madagascar (Crosnier polygyny: in C. oregonensis each male holds 1976). a refuge area—limited resource—which al- VOLUME 102, NUMBER 3 617

4- B

E 3-

2-

1-

~~I W/L RATIO ~T10 12 —r14 Carapace width (cm)

4-

13-

-o 2- Fig. 4. Frequencies of width to length ratios in car- apaces: A, C. porteri; B, C. johngarthi. 1- et al. (1965) who determined a figure of 5 females per each male after one year of I 8 10 12 14 monthly sampling. Carapace width (cm) In the third model, male dominance Fig. 3. Cheliped height plotted against carapace polygyny, mates or critical resources are not width in males: A, Cancer johngarthi; B, Cancer por- economically monopolizable. Males aggre- teri. gate during the breeding season and females select males from these aggregations. Sexual lows him to monopolize females. Preco- dimorphism in the development of che- cious development of strong chelipeds is re- lipeds is not expected here. Orensanz & Gal- quired for an early appropriation of adequate lucci (1988) included C. magister in this refuges. The case of harem defense polygyny category, stressing the fact that C. magister involves direct access to females; therefore, is the only species in the genus Cancer in defense strategies are only needed once re- which chelipeds are of the same size in males productive size is reached. Positive allo- and females. I suggest that this is also the metric growth of chelipeds, consequently, case for C. johngarthi, in absence of di- starts just after the molt of puberty. This morphic development of chelipeds. Several seems to be the case for C. porteri, as in- additional arguments uphold this hypoth- dicated by allometric growth of male che- esis. As expected, sex ratio is almost 1:1 and lipeds (Fig. 3B) and also by data in Antezana sexual selection nearly null; from a total of 618 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON 27 known specimens of C. johngarthi, 15 University), who kindly loaned specimens. are males and the rest females. Since breed- Illustrations were prepared by Clara Yanez ing assemblages are not permanent, breed- and Carlos Sepulveda. ing season should be normally restricted to a short period of time; this seems a reason- Literature Cited able explanation for the lack of ovigerous Antezana, T., E. Fagetti, & M. T. Lopez. 1965. Ob- females in the collected material. servaciones bioecologicas en Decapodos co- On the other hand, there is a relation be- munes en Valparaiso. — Revista de Biologia Ma- tween size of cheliped and quality of sub- rina (Chile) 12:1-60. strate. Species inhabiting soft and homog- Bell, T. 1835. Observations on the genus Cancer of enous bottoms of fine sand have chelipeds Dr. Leach (Platycarcinus Latreille) with descrip- tions of three new species. —Proceedings of the proportionately weaker than those from ir- Zoological Society, London 3:86-88. regular rocky substrates. Lawton & Elner Briggs, J. C. 1974. Marine zoogeography. New York, (1985) stated that these differences account McGraw-Hill, 475 pp. basically for the type of feeding, but they Chirichigno, N. F. 1970. Lista de Crustaceos del Peru left aside an important element of analysis, (Decapoda, Stomatopoda) con datos sobre su distribution geografica. — Informe del Instituto the role of chelipeds in sexual selection, del Mar, Peru 35:1-115. which is common to most decapod Crus- Crosnier, A. 1976. Donnes sur les Crustaces Deca- tacea. Evidently, differences in size and podes captures par M. Paul Gueze a File de la shape of chelipeds of dimorphic species are Reunion lors d'essais de peche en eau pro- not due to differences in diet of each sex; fonde.—Travaux et Documents, ORSTOM 47: male chelipeds fulfill other functions such 225-256. Ekman, S. 1953. Zoogeography of the sea. London, as the defense of a territory or of a harem. Sidgwick & Jackson, 417 pp. Sudden development of cheliped dimor- Emlen, S. T., & L. W. Oring. 1977. Ecology, sexual phism at molt of puberty in many species selection and the evolution of mating systems. — is strong evidence of cheliped morphology Science 197:215-223. depending primarily upon sex require- Faxon, W. 1895. The stalk-eyed Crustacea: Report on an exploration off the west coast of Mexico, ments. Open soft-bottom environments, Central and South America, and off the Gala- compared to complex rocky substrates, al- pagos Islands, in charge of Alexander Agassiz low fewer possibilities of delimitation and by the U.S. Fish Commission Steamer ALBA- defense of a territory; therefore, different TROSS during 1891. XV.-Memoirs of the mating systems are involved. Following this Museum of Comparative Zoology, Harvard 18: idea, lack of dimorphism in chelipeds of C. 1-212. Garth, J. S. 1957. Reports of the Lund University johngarthi may be interpreted as a conse- Chile Expedition 1948-49, No. 29. The Crus- quence of a male dominance polygyny mat- tacea Decapoda Brachyura of Chile. —Lund ing system that in turn results from inhab- University Arsskrifter, (2)53:1-128. iting open soft bottoms. . 1961. Distribution and affinities of the brachyuran Crustacea. — Systematic Zoology 9: 105-123. Acknowledgments Lawton, P., & R. W. Elner. 1985. Feeding in relation to morphometries within the genus Cancer: This paper has been enriched with critical Evolutionary and ecological considerations. Pp. comments by John Garth, Janet Haig, Ray- 357-379 in B. R. Melteff, ed., Proceedings of mond Manning, Jose Orensanz and Ruben the Symposium on Dungeness Biology and Rios. I also thank Dr. Mario Monteforte Management.—University of Alaska, Alaska Sea Grant Reports. (Centro de Investigaciones Biologicas, La MacKay, D. C. G. 1943. Temperature and world Paz, Baja California Sur) and Ardis B. John- distribution of of the genus Cancer.— ston (Department of Invertebrates at the Ecology, 24:113-115. Museum of Comparative Zoology, Harvard Milne-Edwards, H., et H. Lucas. 1844. Crustaces. Pp. VOLUME 102, NUMBER 3 619

1-37 in A. D'Orbigny, ed., Voyage dans l'Ame- . 1930. The cancroid crabs of America. —Bul- rique Meridionale. letin of the United States National Museum 152: Nations, J. D. 1975. The genus Cancer (Crustacea: 1-609. Brachyura): Systematics, biogeography and fos- Retamal, M. A. 1981. Catalogo ilustrado de los Crus- sil record. — Scientific Bulletin of the Natural taceos Decapodos de Chile.—Gayana (Zoolo- History Museum, Los Angeles County 23:1-104. gia) 44:7-110. . 1979. The genus Cancer and its distribution , & L. A. Yanez. 1973. Analisis cuali y cuan- in time and space. —Bulletin of the Biological titativo de los decapodos de los fondos subli- Society of Washington 3:153-187. torales blandos de la Bahia de Conception, Orensanz, J. M., & V. F. Gallucci. 1988. A compar- Chile. —Gayana (Zoologia) 23:1-47. ative study of postlarval life-history schedules Yanez, E. 1974. Distribution y abundancia relativa in four sympatric Cancer species (Decapoda: estacional de los recursos disponibles a un arte Brachyura: ).—Journal of de arrastre camaronero frente a la costa de Val- Biology 8:187-220. paraiso (Invierno y Primavera 1972). —Inves- Parker, R. H. 1964. Zoogeography and ecology of tigaciones Marinas (Chile) 5:125-138. some macroinvertebrates, particularly mol- lusks, in the Gulf of California and the Conti- nental Slope of Mexico.—Videnskabelige Med- Centro de Investigation Cientifica y de delelser fra Dansk Naturhistorisk Forening 126: Education Superior de Ensenada, Apartado 1-178. Postal 2732, Ensenada, B.C., Mexico. Pres- Rathbun, M. J. 1910. The stalk-eyed Crustacea of ent address, Instituto Professional de Osor- Peru and the adjacent coast. —Proceeding of the United States National Museum 38:531-620. no, Casilla 933, Osorno, Chile.