First records of the Redfin Brotula , Petrotyx sanguineus ( Meek & Hildebrand , 1928 ) ( Ophidiiformes , Bythitidae ) , in the western South Atlantic

The present study reports on the first records of the bythitid Redfin Brotula, Petrotyx sanguineus (Meek & Hildebrand, 1928), in the western South Atlantic, based on 7 specimens (50.8–152.8 mm SL) from 5 localities along the northeastern coast of Brazil: (1) Praia de Maracaípe, Ipojuca and (2) Praia de Tamandaré, Tamandaré, in Pernambuco state; and (3) Praia do Forte, Mata de São João, (4) Praia de Busca Vida, Camaçari, and (5) Barra do Pote, Vera Cruz, in Bahia state. This species was previously known only in the western Central Atlantic, from Bahamas to Trinidad and Tobago, including the Caribbean Sea. In addition to the new distributional information, morphological data are provided based on the specimens examined.


Introduction
According to Nelson et al. (2016), the order Ophidiiformes includes 5 families (Aphyonidae, Bythitidae, Carapidae, Parabrotulidae, and Ophidiidae), 119 genera and about 530 species.Recently, Møller et al. (2016) introduced a new classification for the viviparous clade, merging Bythitinae, Brosmophysini and Aphyonidae into Bythitidae, and elevating Dinematichthyidae (formerly tribe Dinematichthyini) to family status.Recent studies on the diversity of ophidiiforms from Brazil reported the occurrence of 45 species from 33 genera and 3 families from both coastal and deep-sea waters (Franco et al. 2007, Mincarone et al. 2008, Nielsen 2009, Nielsen et al. 2009, 2015).In this study, the Redfin Brotula, Petrotyx sanguineus (Meek & Hildebrand, 1928), a reef species previously known from the western Central Atlantic (Nielsen et al. 1999), is reported for the first time in the western South Atlantic, based on 7 specimens obtained from 5 localities along the northeastern coast of Brazil.
were identified following the descriptions and diagnoses provided by Meek and Hildebrand (1928), Böhlke (1955), Cohen andNielsen (1978), andNielsen et al. (1999).An updated distribution map of P. sanguineus based on the literature, photographic material, and museum specimens is also provided.
Identification.The genus Petrotyx is diagnosed by the following combination of characters: lips with series of dermal fringes; snout with numerous small and fleshy papillae; snout and chin without barbels; eyes relatively small; posterior margin of preopercle covered by skin; opercle and preopercle without spines; presence of sheath in the upper margin of maxilla; apparently no pores on head; 3 developed gill rakers on the first branchial arch; 8 branchiostegal rays; teeth presented in bands on jaws, vomer, and palatines; 1 median basibranchial tooth patch; single lateral line restricted to the anterior half of the body; pelvic fins inserted posterior to the tip of humeral symphysis; pelvic fins with 2 rays; lower pectoral-fin rays not separated; dorsal, anal, and caudal fins confluent posteriorly; 12 precaudal vertebrae; head and body scaled (Bölhke 1955, Nielsen et al. 1999).
The juveniles of P. sanguineus have a uniform reddish-orange coloration.The adult specimens are reddish-brown, with fins bright red, and margins of dorsal, caudal and anal fins dark.The specimens recorded in Brazil have a darker coloration, probably because they were collected after death.

Discussion
Petrotyx sanguineus is a reef dwelling species with secretive habit, known in the western Central Atlantic, from Bahamas to Trinidad and Tobago, including USA (Florida), Mexico (Quintana Roo), Belize, Turks and Caicos Islands, Cayman Islands, Haiti, Puerto Rico, Virgin Islands, Dominica, Panama, Colombia (Santa Marta and Isla de Providencia), Venezuela, and Curaçao (Böhlke and Chaplin 1968, Robins and Ray 1986, Cervigón 1991, Nielsen and Robins 2003, Smith et al. 2003, museum records).The present study provides the southernmost records of P. sanguineus in the western Atlantic, on the coasts of Pernambuco and Bahia states, Brazil (Fig. 2).The species can be found in reefs, from 3 to 21 m depth (Böhlke andChaplin 1968, Nielsen et al. 1999).
With a few exceptions, the measurements and counts of specimens from Brazil are within the morphological variations observed among the specimens from the Caribbean Sea (Table 1).However, we found that some diagnostic characters proposed by Bölhke (1955) are different from those observed for the specimens currently examined (dorsal-fin rays 86-91 vs 81-96; anal-fin rays 68-72 vs 63-74, respectively).In general, the specimens examined in this study have a wider range (both minimum and maximum values) when compared with those proposed by Bölhke (1955).This could be an effect of the sample size, as we have examined more specimens (n = 16) than Bölhke (1955;n = 5).The examination of additional specimens from other western Atlantic localities could clarify our understanding on such morphological variations.
Recent studies on the diversity of ophidiiforms from Brazil include those of Mincarone et al. (2008), who reported the occurrence of 45 species (of which 44 are currently valid).Subsequently, Nielsen et al. (2009) reviewed the ocellus-bearing species of Neobythites from the western Atlantic, which resulted in the description of Neobythites multiocellatus Nielsen, Uiblein & Mincarone,

Figure 1 .
Figure 1.Photographic records of Petrotyx sanguineus along the northeast Brazilian coast.A. Specimen (c. 150 mm SL) found dead on a reef formation on the Praia de Busca Vida, Camaçari, Bahia.B. Specimen (82 mm SL) found dead on the Praia de Maracaípe, Porto de Galinhas, Pernambuco.C. Dried specimen (c.70 mm SL) found dead on Praia do Forte, Mata de São João, Bahia.

Figure 2 .
Figure 2. Distribution of Petrotyx sanguineus in the Atlantic Ocean, including: type locality (open circle), literature and museum records in the western Central Atlantic (black circles), and new records along northeast Brazilian coast (stars).

Table 1 .
Measurements and counts for the Redfin brotula Petrotyx sanguineus from northeastern Brazil and Caribbean Sea.
Pinheiro et al. (2018), the current list of ophidiiform fishes recorded in Brazilian waters, followingMøller's et al. (2016)classification, includes 34 genera and 46 species: 9 species of Bythitidae (including P. sanguineus), 4 Carapidae, and 33 Ophidiidae.In a recent study,Pinheiro et al. (2018)reported the presence of 405 resident reef fish species in the western South Atlantic, of which 186 species (46%) are widely distributed in the western Atlantic.The occurrence of P. sanguineus in the northeastern Brazil represents another example of species shared by central and southwestern Atlantic reefs.