New records and bathymetric distribution of deep-sea shrimps of the family Glyphocrangonidae (Decapoda: Caridea) from the Potiguar Basin, northeastern Brazil

Th e caridean family Glyphocrangonidae Smith, 1884 is monotypic, including only the genus Glyphocrangon A. Milne-Edwards, 1881. Th e species of this genus are exclusively inhabitants of deep sea. Th e current contribution aims to enrich the knowledge of Glyphocrangon in the southwestern Atlantic, by reporting its occurrence and bathymetric distribution in the Potiguar Basin, northeastern Brazil. Th e samples were collected by R/V Luke Th omas and R/V Seward Johnson, with bott om trawling at isobaths of 400, 1,000 and 2,000 m, using an ott er trawl semi-balloon. Th e specimens were identifi ed and stored in the carcinological collection of the Museu de Oceanografi a Prof. Petrônio Alves Coelho, in Recife, Brazil. A total of 810 specimens were examined from fi ve species: Glyphocrangon aculeata A. Milne-Edwards, 1881, G. alispina Chace, 1939, G. longirostris (Smith, 1882), G. sculpta (Smith, 1882) and G. spinicauda A. Milne-Edwards, 1881. Glyphocrangon spinicauda

Th e caridean family Glyphocrangonidae Smith, 1884 is monotypic, including only the genus Glyphocrangon A. Milne-Edwards, 1881.Th e species of this genus are exclusively inhabitants of deep sea.Th e current contribution aims to enrich the knowledge of Glyphocrangon in the southwestern Atlantic, by reporting its occurrence and bathymetric distribution in the Potiguar Basin, northeastern Brazil.Th e samples were collected by R/V Luke Th omas and R/V Seward Johnson, with bott om trawling at isobaths of 400, 1,000 and 2,000 m, using an ott er trawl semi-balloon.Th e specimens were identifi ed and stored in the carcinological collection of the Museu de Oceanografi a Prof. Petrônio Alves Coelho, in Recife, Brazil.A total of 810 specimens were examined from fi ve species: Glyphocrangon aculeata A. Milne-Edwards, 1881, G. alispina Chace, 1939, G. longirostris (Smith, 1882), G. sculpta (Smith, 1882) and G. spinicauda A. Milne-Edwards, 1881.Glyphocrangon spinicauda

MaterIal and Methods
The Potiguar Basin, situated in the extreme northeast of Brazil, between the states of Rio Grande do Norte (RN) and Ceará (CE) (Fig. 1), belongs to a group of mesocenozoic basins that form the coastal province of the Brazilian continental margin.It comprises approximately 38,500 km², distributed between the continental shelf and the continental slope, to the depth of 2,000 m (Bertani et al., 1990;Alves-Júnior et al., 2016a, b).
The samplings were carried out from the R/V Luke Thomas in 2009 "Arrasto Malha Talude" (AR and ARMT samples) and from the R/V Seward Johnson in 2011 "Malha Talude" (MT samples).Bottom trawls of an approximately 30 minutes duration were conducted on the continental slope along the isobaths of 400 m, 1,000 m and 2,000 m, using a semi-balloon otter trawl with 50 mm mesh size and 18 m opening.The specimens were preserved in 70% ethanol.
Remarks.The examined specimens have the diagnostic characters of G. aculeata as described by Smith (1882), Holthuis (1971) and Komai (2004a).Glyphocrangon aculeata is easily recognized among the Atlantic species of the genus by the anterior fourth carina of the carapace forming a vertically compressed, acute lamina (wing-like spine).
Along the Brazilian coast, G. aculeata was first recorded by Spence Bate (1888) on the basis of material collected off Recife (state of Pernambuco), at a depth of 1,215 m.Komai (2004a) extended its distribution to the states of Bahia and Espírito Santo, between 707-1,760 m depth.The present record is the first from Potiguar Basin and fills a gap in the distribution of G. aculeata in the south Atlantic, suggesting that this species is much more widely distributed than currently assumed.
Females were more abundant and larger in size than compared to males (see Tab. 2).
Bathymetric distribution.In the state of Florida, G. alispina was found between depths of 548-1,865 m (Holthuis, 1971), whilst in the southwest and southeast of the Gulf of Mexico, there are records between depths of 671, 9-1,144 m (Vázquez-Bader and Gracia, 2013).It has been recorded off the Brazilian coast between 421-900 m depths (Serejo et al., 2007).However, in this study, the species was found between depths of 908-2,094 m, thus extending its known bathymetric distribution.
Remarks.The specimens examined are in agreement with the original description of Chace (1939) and the subsequent redescription of Holthuis (1971).Holthuis (1971) mentioned that G. alispina is very similar to G. nobilis A. Milne-Edwards, 1881.Further, Komai (2004a) showed some differences between the species, such as: the size of the eye being larger in G. alispina than in G. nobilis, and the fourth and fifth pereopods more elongate in G. alispina than in G. nobilis.The material examined herein fits well with these states of characters.
Females were more abundant and larger in size when compared to males (see Tab. 2).
Bathymetric distribution.The species was previously recorded in depths of 1,280-2,500 m (Holthuis, 1971).In southeastern Brazil it has been recorded between depths of 1,402-2,076 m (Serejo et al., 2007), with the current specimens found between the depths of 908-2,094 m.
Remarks.The present specimens adhere closely to the descriptions of Smith (1882), Holthuis (1971), Komai (2004a) and Cardoso and Serejo (2007).Glyphocrangon longirostris shares a character with G. nobilis and G. alispina, such as the anterior lateral carina of the carapace armed with only one terminal spine (Komai, 2004a).However, the absence of short setae on the carapace and abdomen, and the presence of a dorsal rugosity on the rostrum easily distinguish G. longirostris from those species.Glyphocrangon longirostris has a wide geographical distribution in the Atlantic Ocean (both western and eastern) (Holthuis, 1971).However, this species was only recorded from Brazil rather recently by Komai (2004a).Later, Cardoso and Serejo (2007) recorded the species from the Campos Basin, off the coast of Rio de Janeiro.This study reports the occurrence of the species in the Potiguar Basin for the first time.
Females were more abundant and larger in size when compared to males (Tab.2).
Bathymetric distribution.Serejo et al. (2007) obtained specimens in Brazilian waters from 1,718-2,137 m depth.The present specimen came from exclusively at 2,094 m.Remarks.Holthuis (1971) diagnosed G. sculpta as having three teeth on the fifth pleonal pleuron as does the present specimen.However, Pequegnat (1970) and Komai (2004b) stated that the armature is variable, sometimes having only two teeth.As shown by previous authors (Holthuis, 1971;Komai, 2004a), G. sculpta is easily recognizable among the Atlantic species by the spiny intercarinal spaces of the carapace, the clearly bidentate anterior fourth carina on the carapace and subcylindrical dactyli of the fourth and fifth pereopods, with the distal part horizontally cleft in females.
In the western Atlantic G. sculpta has a disjunct distribution, occurring along the east coast of the United States, between Massachusetts and Delaware, to the Caribbean (Holthuis, 1971) and in Brazil, off the coast Rio Grande do Norte (present study), Bahia and Rio de Janeiro (Komai, 2004a).The material studied herein is the second record of the species along the Brazilian coast, filling a gap in its geographical distribution.
In the present study, the species was found between the depths of 389-480 m.
Remarks.The material examined corresponds to the descriptions in Holthuis (1971) and Komai (2004a).Komai (2004a: 41) assumed the first record of this species from Brazilian waters based on material collected by the project REVIZEE Score Central off Bahia coast.This author pointed out that G. spinicauda has been cited on an unpublished conference abstract record by Ramos-Porto & Silva (2000).However, Komai (2004a) probably overlooked that Holthuis (1971) had already recorded this species in Brazil on the basis of eight ovigerous females collected at station of "Oregon" St. 2081 off the outfall of the Amazon River in the state of Pará.This record was cited by both Coelho and Ramos (1972) and Ramos-Porto and Coelho (1998).Also, Ramos-Porto et al. (2000;2003) recorded this species in Amapá, Pará and Maranhão, based on the material collected by the project "REVIZEE/Pesca" in the northern region of Brazil.The present record is the first from the study area.
Females were more abundant and larger in size when compared to males (see Tab. 2).

abundance and bathyMetrIc dIstrIbutIon
The species of Glyphocrangon were represented in three out of seven sampling stations in 2009, and 18 out of 31 stations in 2011 (ranging in depths between 400-2,000 m) (Tab.1).A total of 810 shrimps were examined, belonging to five species: G. aculeata, G. alispina, G. longirostris, G. sculpta and G. spinicauda (Fig. 7).The most abundant species was G. spinicauda, which is usually found as a fishery by-catch in the north of Brazil (Ramos-Porto et al., 2000).
The specimens of G. aculeata were found only around 1,000 m, while G. sculpta was registered only at a depth of 2,000 m.Both records are included in the bathymetric distribution limits known for the species (Komai, 2004a;Serejo et al., 2007;Vázquez-Bader and Gracia, 2013).The highest abundance of individuals of G. spinicauda was recorded around 400 m depth, although the previous records by Holthuis (1971) and Ramos-Porto et al. (2000) have registered this species deeper as far as 692 m.The wide bathymetric range of G. alispina and G. longirostris has also been observed by Wenner (1978) and Komai (2004a), indicating a better tolerance to high variations of pressure, temperature and salinity compared to the others species of the genus.The larger proportion of ovigerous females was observed in four out of the five species reported in this study with ovigerous females being larger in size than non-ovigerous females and males.Thompson (1963) studied species of Glyphocrangon in the north Atlantic and suggested that spawning occurs all year long, due to a large proportion of sexually mature individuals in the population.
Thus, due to the low sampling effort in deep waters beyond the continental slope, the record of these species in the southwestern Atlantic (Potiguar Basin) is an important advancement to foster the knowledge

acKnowledgeMents
The first author thanks FACEPE for a postgraduate scholarship in Oceanography (protocol number IBPG-1376-1.07/12),which supported this research, and Petróleo Brasileiro S.A. (Petrobrás) for the availability of the material for this study.The authors would like to thank the anonymous reviewers for their precious comments on this paper and also Dr. Sammy De Grave for the English review and valuable suggestions.This paper was presented at the 8 th International Crustacean Congress in Frankfurt, chaired by Dr. Michael Türkay (in memoriam).

Figure 1 .
Figure 1.Location of the sampling stations between the states of Rio Grande do Norte and Ceará, northeast of Brazil.

Figure 7 .
Figure 7. Number of specimens of Glyphocrangon A. Milne-Edwards, 1881 based on the depth in Potiguar Basin, northeastern Brazil.

Table 1 .
Stations list for the species of Glyphocrangon A. Milne-Edwards, 1881 with station number, sampling date, locality, initial and final coordinates of the trawl, initial and final depth of trawl and depth in the Potiguar Basin, northeastern Brazil.

Table 2 .
Minimum, mean and maximum values of biometric variables (TL and CL) in males, non-ovigerous females and ovigerous females from species of the genus Glyphocrangon A. Milne-Edwards, 1881 in the Potiguar Basin, northeastern Brazil.