Marine Biology (2006) 149: 491–502 DOI 10.1007/s00227-005-0232-x RESEARCH ARTICLE J. Gusma˜o Æ C. Lazoski Æ F. A. Monteiro A. M. Sole´-Cava Cryptic species and population structuring of the Atlantic and Pacific seabob shrimp species, Xiphopenaeus kroyeri and Xiphopenaeus riveti Received: 17 August 2005 / Accepted: 26 September 2005 / Published online: 10 January 2006 Ó Springer-Verlag 2006 Abstract Seabob shrimps of the genus Xiphopenaeus are cific distances ranged from 0 to 0.008 in Xiphopenaeus important fishery resources along the Atlantic and sp. 1, from 0 to 0.003 in Xiphopenaeus sp. 2, and from Pacific coasts of Central and South America. The genus 0.002 to 0.005 in X. riveti. In addition, five diagnostic was considered to comprise two species: the Atlantic allozyme loci were found between sympatric samples of Xiphopenaeus kroyeri (Heller, Sitzungsber Math Natur- Xiphopenaeus sp. 1 and 2 along the Brazilian coast. The wiss cl kaiserliche Akad Wiss Wien 45:389–426, 1862), results suggest that Xiphopenaeus sp. 2 from the Atlantic and the Pacific Xiphopenaeus riveti (Bouvier, Bull Mus is more closely related to the Pacific X. riveti than to the Hist Nat Paris 13:113–116, 1907). In a recent review, Atlantic Xiphopenaeus sp. 1. Furthermore, a high level of Xiphopenaeus was regarded as a monotypic genus, on genetic structuring (Xiphopenaeus sp. 1: FST=0.026; the basis that no clear morphological differences could P<0.05; Xiphopenaeus sp. 2: FST=0.055; P<0.01) was be found between Pacific and Atlantic specimens (Pe´rez found in the Brazilian Xiphopenaeus populations, indi- Farfante and Kensley, Mem Mus Nat Hist Nat Paris cating the presence of different genetic stocks in both 175:1–79, 1997). In the present work, nuclear (allo- Atlantic species. These findings have important com- zymes), and mitochondrial (Cytochrome Oxidase I) mercial implications as they show that the fisheries of the genes were used to demonstrate the validity of X. riveti two Atlantic species must be managed separately, and and reveal the presence of two cryptic species of Xip- that each one is comprised of different populations. hopenaeus within X. kroyeri in the Atlantic Ocean. The high levels of molecular divergence among these species contrast with their high morphological resemblance. Interspecific sequence divergences (Kimura 2-parameter Introduction distance) varied from 0.106 to 0.151, whereas intraspe- Penaeid shrimp species are important economic Communicated by O. Kinne, Oldendorf/Luhe resources in many countries (Sunden and Davis 1991). In the West Atlantic, the seabob, Xiphopenaeus kroyeri J. Gusma˜ o Æ C. Lazoski Æ A. M. Sole´-Cava (Heller 1862) is one of the most common native shrimp Departamento de Gene´tica, Laborato´rio de Biodiversidade Molecular, Instituto de Biologia, UFRJ, Bloco A, CCS, Ilha do species. In Guyana, Suriname, and the East coast of the Funda˜ o, 21941-490 Rio de Janeiro, Brazil United States, the average production of X. kroyeri E-mail: [email protected] between 1999 and 2003 was 17,500, 9,600, and 3,200 tons/year, respectively (FAO 2005). In Brazil, the & J. Gusma˜ o( ) average production of X. kroyeri in the same period was Departamento de Biologia Celular e Gene´tica, Laborato´rio de Gene´tica Marinha, Instituto de Biologia Roberto Alcaˆ ntara 11,500 tons/year, higher than the 7,400 tons/year of Gomes, UERJ, Rua Sa˜ o Francisco Xavier 524, Maracana˜ , Farfantepenaeus brasiliensis and close to the 12,000 tons/ 20550-900 Rio de Janeiro, Brazil year for the sum of all other native Penaeus (sensu lato E-mail: [email protected] Fabricius 1798) species (FAO 2005). F. A. Monteiro The genus Xiphopenaeus Smith 1869 was considered Departamento de Medicina Tropical, Instituto Oswaldo Cruz, to be comprised of two species: the Atlantic X. kroyeri, Fiocruz, Av. Brasil 4365, 21045-900 Rio de Janeiro, Brazil and the Pacific Xiphopenaeus riveti (Bouvier 1907). However, in a recent review, X. riveti was considered to A. M. Sole´-Cava X. kroyeri Department of Environmental and Evolutionary Biology, Port be a junior synonym of based on lack of Erin Marine Laboratory, University of Liverpool, Isle of Man, significant morphological differences between the Pacific United Kingdom and Atlantic specimens, thus making Xiphopenaeus 492 monotypic (Pe´rez Farfante and Kensley 1997). As a for clarifying the taxonomic status of Atlantic and Pacific consequence of the synonymy, the distribution of Xiphopenaeus spp. X. kroyeri now ranges from North Carolina (USA) to Floriano´polis (Brazil) in the Atlantic, and from Sinamoa (Mexico) to Paita (Peru), in the Pacific (Fig. 1;Pe´rez Materials and methods Farfante and Kensley 1997). In a recent attempt to develop a molecular diagnostic Collection of samples system to identify different Brazilian commercial shrimp species, two different PCR/RFLP haplotypes of the For allozyme analyses, 176 individuals of X. kroyeri cytochrome oxidase I (COI) mtDNA gene were found were obtained directly from fishermen straight after within populations of X. kroyeri from Northeast Brazil disembarkation of small trawlers, from five different (Gusma˜ o and Sole´-Cava 2002). Moreover, a recent locations along the Brazilian coast (Natal 5°52¢S/ allozyme study of X. kroyeri from Southeast Brazil 35°10¢W; Poc¸as 11°46¢S/37°32¢W; Nova Almeida found very large heterozygote deficiencies (Voloch and 20°03¢S/40°11¢W; Arraial do Cabo 22°58¢S/42°01¢W; Sole´-Cava 2005). In order to verify if those deficiencies, and Ubatuba 23°26¢S/45°04¢W; Fig. 1). The samples as well as the PCR/RFLP differences, could result from were collected between February and August 2001, and the existence of cryptic species, as already observed in cover about 2,500 km distance and a comprehensive other Atlantic penaeid species (Gusma˜ o et al. 2000), we range of the species distribution along the Brazilian used allozymes and COI sequences to compare samples coast. The samples were transported on dry ice to the of several X. kroyeri populations from both the Atlantic laboratory, where they were morphologically identified and Pacific coasts of Latin America. per classification system of Pe´rez Farfante and Kensley DNA sequencing of the observed COI haplotypes, (1997). A sample of muscle tissue of each individual was and allozyme analyses reveal the presence of two differ- stored in liquid nitrogen until required for allozyme ent cryptic Xiphopenaeus species in the Atlantic. COI studies or DNA purification. sequencing also demonstrates that the Pacific X. riveti is a Twelve individuals from Caravelas (Bahia 17°44¢S/ valid species. The large genetic divergence found among 39°15¢W), collected in January 2005, were used for hap- the three species contrasts with their high morphological lotype PCR/RFLP scoring, and DNA sequencing of a resemblance. These findings have important implications part of the COI gene of three of those specimens was Fig. 1 Xiphopenaeus kroyeri sampling sites. Gray area: putative geographic distribution of X. kroyeri (sensu Pe´rez Farfante and Kensley 1997) 493 performed. Four X. kroyeri individuals collected in primers COIf[5¢-CCT GCA GGA GGA GGA GA(C/ Panama City (Pacific Ocean) (8°53¢N/79°35¢W; Fig. 1) T) CC-3¢] (Palumbi and Benzie 1991) and CO10 [5¢-TAA and three collected in Caracas (Venezuela 10°36¢N/ GCG TCT GGG TAG TCT GA(A/G) TA(T/G) CG-3¢] 66°59¢W; Fig. 1), in July and November 2004 respec- (Baldwin et al. 1998). PCR reactions were performed in tively, were used for COI sequencing. Total DNA a PTC-100 Mini-cycler (MJ Research) programmed for extractions were performed using a modified CTAB one denaturation step at 94°C for 3 min, followed by 40 protocol (Damato and Corach 1994; Gusma˜ o and Sole´- cycles at 94°C for 1 min, 51°C for 1 min, and 72°C for Cava 2002). 45 s, and a final 5 min extension step at 72°C, as per Gusma˜ o and Sole´-Cava (2002). Negative controls, con- sisting of template-free reactions, were included in all Allozyme analyses PCR amplifications. Before purification, 5 ll of each PCR reaction were used for endonuclease cleavage for Analyses were conducted using horizontal 12.5% starch scoring composite Hinf I/Hinc II haplotypes, applying gel electrophoresis and standard methodology (Murphy the previously developed PCR/RFLP diagnostic system et al. 1990; Gusma˜ o et al. 2000). Combinations of the (Gusma˜ o and Sole´-Cava 2002). buffer and enzyme systems are shown in Table 1. DNA sequencing was carried out using standard Allozyme patterns were revealed using standard enzyme procedures (Hoelzel and Green 1992). Purification of stains (Manchenko 1994). Genotype frequencies were PCR products was performed with a GFXä PCR DNA used to estimate gene frequencies, heterozygosities, and and Gel Band Purification Kit (Amersham Pharmacia unbiased genetic identities and distances (I and D; Nei Biotech, Germany), following the manufacturer’s 1978). Genetic identities were used to construct a instructions. Direct sequencing of both fragment strands UPGMA tree (Sneath and Sokal 1973). These data were was conducted through the use of a fluorescent dye- analysed using the program BIOSYS Version 1.7 terminator cycle sequencing reaction (Thermo Sequen- (Swofford and Selander 1981). Node support of the aseä Dye Terminator Cycle Sequencing Kit), using an UPGMA tree was estimated through bootstrap pseudo- ABI 377 Perkin Elmer automatic sequencer (Perkin replication (Efron 1981; Felsenstein 1985) with the Elmer Inc., USA). Twenty-two X. kroyeri samples from DISPAN program (Ota 1993). F-statistics were esti- Atlantic populations and four from the Pacific coast of mated according to Weir and Cockerham (1984). The Panama were sequenced (Table 2). significance of FIS (Ho: FIS=0) and FST (Ho: FST=0) were tested according to Waples (1987), using a per- mutation approach (with 1,000 replicates).