First record of Pentapycnon geayi Bouvier, 1911 (Pycnogonida: Pycnogonidae) in the state of Ceará, northeastern Brazil

: Contributions to the knowledge of the Pycno-gonida fauna along the Brazilian coast are scarce. There are only 60 records for the coast of Brazil, and reports of this fauna are notably discontinuous. This is the first record of Pentapycnon geayi Bouvier, 1911 (Pycnogonida: Pycnogoni-dae) in the state of Ceará. This study adds a new bathymet-ric record and fills a gap in the distribution of P. geayi along the Brazilian coast. This report also provides important new data for Ceará because the diversity of Pycnogonida in this state is practically unknown.

The family Pycnogonidae Wilson, 1878 encompasses three genera: Pentapycnon Bouvier, 1910, Pycnogonum Brünnich, 1764, and Pycnopallene Stock, 1950(Bamber 2009).The genus Pentapycnon belongs to a group of polymeric pycnogonids that are characterized by one or two additional somites posterior to the fourth somite, and thus have five or six pairs of legs.The genus is composed of three species: Pentapycnon bouvieri Pushkin, 1993 and P. charcoti Bouvier, 1910 (Antarctic and Subantarctic regions), and P. geayi Bouvier, 1911 (Caribbean Sea to the Southwestern Atlantic Ocean) (Bouvier 1911;Hedgpeth 1948;Stock 1975Stock , 1992;;Child 1995;Krapp & Viquez 2011).The pres-ent record of P. geayi is the first for the state of Ceará, and therefore fills a gap in this species' distribution along the Brazilian coast between the states of Pará and Rio Grande do Norte.It is also the first record of the family Pycnogonidae from Ceará.
The fieldwork took place at four beaches along the coast of Ceará, northeastern Brazil (Pacheco, Dois Coqueiros, Caponga, and Ponta Grossa beaches).Specimens were captured by hand by two persons for 1 hour (CPUE) in tide pools in the mesolitoral zone during spring low tides.In the laboratory, specimens were identified following the original description of Bouvier (1911), and recent taxonomy and systematic group work using the current terminology (Stock 1975(Stock , 1986(Stock , 1992;;Child 1995;Arango 2000Arango , 2002;;Bamber 2009;Mueller & Krapp 2009;Krapp & Viquez 2011), sexed, and measured to ±0.01 mm with an ocular micrometer.The individuals were fixed in ethanol 70%, and deposited in the invertebrate collection of the Laboratório de Invertebrados Marinhos do Ceará (LIMCE-UFC), Universidade Federal do Ceará, in Fortaleza, state of Ceará, Brazil.All samplings in this study were conducted in compliance with current applicable federal laws (SISBIO 28854-1).
According to Bamber (2009), Pentapycnon geayi belongs to the superfamily Pycnogonoidea Pocock, 1904 and the family Pycnogonidae Wilson, 1878.The following description of P. geayi was based on the original description of Bouvier (1911).The male of P. geayi has short, robust and stout body and legs with tegument strongly reticulate; brownish cream in colour, trunk compact, fully segmented, with small granules in the cuticle and four strong tubercle dorsomedian placed directly posterior to ocular process (tubercle); proboscis conical, distally tapering; lateral processes or (crurigers) short touching at bases, or slightly apart almost touching, and its distal region has a margin with small tubercles; five pairs of legs, moderately short and robust; propodus with small single terminal claw and strong; ocular tubercle circular in dorsal view placed at middle region of cephalic, higher than other dorsomedian tubercles, four equidistant small eyes, darkly pigmented; abdomen horizontal, jointed from underneath the fifth segment; ovigers relatively small and short 7-segmented, with strong, curved terminal claw.The female has the same morphological characteristics of the male, with the exception of the ovigerous that are exclusive of the males.In life, the individuals were brownish-cream in colour (Figures 1-4).
Pentapycnon geayi is similar to its Antarctic/Subantarctic congeners P. bouvieri and P. chacorti.However, P. geayi can be distinguished by the presence of the strongly reticulate tegument.Pentapycnon bouvieri and P. chacorti present the ocular tubercle placed at the extreme anterior edge of the cephalic segment, while in P. geayi the ocular tubercle is placed at the middle of the cephalic region.The ovigers in P. geayi are short, 7-segmented, and with a strong curved rubble habitats in the sublitoral, with some species showing preference for a specific substratum (sea weeds, coral rubbles) and others with no special preference (Müller & Krapp 2009).This is the first time that this species was found in association with other invertebrates, especially the sand anemone.
Pentapycnon geayi is the only species of the genus Pentapycnon recorded in Brazil.All previous records of the species by Stock (1975Stock ( , 1992) ) along the Brazilian coast involved material collected in deeper waters (15-25 m depth).Here P. geayi was recorded from depths of 0-2 m.All specimens were caught in tide pools in intertidal sandstone reefs during low tide, extending the bathymetric distribution shoreward for this species.Previous studies realized in other countries (French Guiana and Puerto Rico) showed that bathymetric distribution of P. geayi ranges from depths of 5-11 m (Hedgpeth 1947;Krapp & Viquez 2011).
The material of this study was collected in the intertidal zone, which indicates that the species has a broad bathymetric range, and could live in association with other invertebrates, such as the sand anemone Actinostella flosculifera.This is the first record of the species in the state of Ceará, thus filling a gap in its geographic distribution in the Western Atlantic.terminal claw, while in P. bouvieri and P. chacorti ovigers are 9-segmented, with a slightly curved terminal claw.In P. geayi the proboscis is conical and distally tapering, while in P. bouvieri, the proboscis is broadly tapering distally to a rounded oral surface, and in P. chacorti, the proboscis is a distally tapering cylinder bearing three rounded distal tubercles (Child 1995).
Until now, 38 nominal species were reported from tropical waters south of the mouth of Amazon and with 12 species known exclusively from Brazilian waters (Müller & Krapp 2009).Pentapycnon geayi is one of the 19 species shared between the Brazilian and Caribbean regions.According to Müller & Krapp (2009) the existence of a Brazilian faunal province appears rather probable, but more data are needed from this region to support this thesis.The present record of P. geayi in Ceará helps to better understand the fauna of the region and the zoogeography affinities as well.
One male from Ponta Grossa (Icapuí) was collected on the sand anemone Actinostella flosculifera (Le Sueur, 1817).The other specimens were found on tunicates, sponges, and macroalgae.Pycnogonids are almost exclusively freeliving, errant invertebrates (Bamber 2007), but some species are known to show preference either for seagrass stands or algal substrata in the mesolitoral and for coral  (Stock 1975(Stock , 1992)).