Lutjanus alexandrei, Rodrigo L. Moura & Kenyon C. Lindeman, 2007

Rodrigo L. Moura & Kenyon C. Lindeman, 2007, A new species of snapper (Perciformes: Lutjanidae) from Brazil, with comments on the distribution of Lutjanus griseus and L. apodus., Zootaxa 1422, pp. 31-43 : 33-37

Lutjanus alexandrei , new species

(Figures 1-3; Tables 1, 2)

Lutjanus apodus not of Walbaum, 1792. Jordan, 1891:330 (Bahia); Ribeiro, 1915 (not paginated); Jordan & Fessler, 1893:510 (Pernambuco); Gilbert, 1900:170; Starks, 1913:32; Fowler, 1941:160; Allen, 1985:56 (in part); Carvalho-Filho, 1994:138 (in part); Rocha et al., 1998:562; Rocha & Rosa, 2001:990; Moura & Menezes, 2003:82 (in part).

Lutjanus griseus not of Linnaeus, 1758. Ribeiro, 1915 (not paginated, in part); Ribeiro, 1918 (not paginated, in part); Menezes & Figueiredo, 1980:22 (in part), Carvalho-Filho, 1994:135 (in part); Moura & Menezes, 2003:83 (in part).

Holotype: MZUSP 65664 (153) Camurupim Reef, Tamandaré (8°49'S, 35°5'W), State of Pernambuco, Brazil, 05 m depth; collected by R.L. Moura, R.B. Francini-Filho & C.H. Flesh, 22 January 1999.

Paratypes (21 specimens, 69-243): USNM 388233 (1, 161), Abrolhos Bank (17°57’08”S, 38°41’W), State of Bahia, Brazil, 20 m depth, collected by R.L. Moura & R.B. Francini-Filho, 1 April 2000. MZUSP 52721 (2, 227-243) Parcel dos Abrolhos (17°57’ 08 S ”, 38°41’6”W), Abrolhos Bank, State of Bahia, Brazil, collected by R.L. Moura, R.B. Francini-Filho, C. Sazima & I. Sazima, 22 January 1998. MZUSP 84862 (1, 108), collected with the holotype. MZUSP 66066 (1, 131) Itaparica (12°52’S, 38°41’W), State of Bahia, Brazil, collected by A. Carvalho-Filho, October 1982. MZUSP 60838 (1, 150) Parcel das Paredes (17°53’54”S, 38°57’13”W), Abrolhos Bank, State of Bahia, Brazil, collected by R.L. Moura, C.E.L. Ferreira & R.B. Francini-Filho, 19 February 2000. MZUSP 66021 (3, 82-95) Salvador (12°56’S, 38°31’W), State of Bahia, Brazil, collected by V.G. Almeida, 21 July 1970. MZUSP 65939 (3, 71-89) same locality as MZUSP 66021, collected by C.E. Dawson, N.A. Menezes & V.G. Almeida. MZUSP 66020 (1, 82) same locality as MZUSP 66066, collected by N.A. Menezes & V.G. Almeida, 24 August 1972. MZUSP 66022 (5, 69-128), Lagoa Mundaú (09°37’S, 35°48'W), Maceió, State of Alagoas, Brazil, collected by CETESB, 1985. MZUSP 66026 (1, 79) Ponta de Pedras (8°3’S, 34°46’W) State of Pernambuco, Brazil, collected by P. Montouchet, 30 August 1970. MZUSP 51167 (1, 87), same data as MZUSP 66022. MZUSP 65062 (1, 91) Fortaleza (3°45'S 38°20'W) State of Ceará, Brazil, 0.5m depth (tidepool), collected by R.L. Moura, R.B. Francini-Filho & C.H. Flesh, 26 March 2000.

Diagnosis. Among western Atlantic snappers, Lutjanus alexandrei is similar to the gray snapper, Lutjanus griseus (Linnaeus) , and the schoolmaster, Lutjanus apodus (Walbaum) , with which it shares the following characters: 14 soft dorsal-fin rays, 6 (5-7 in L. apodus ) scales between lateral line and dorsal-fin origin, anchor-shaped vomerine tooth patch with a median posterior extension, upper canines much larger than lower canines. Lutjanus alexandrei differs from L. griseus by the presence of 6 pale vertical bars (sometimes faded) on the trunk (absent in L. griseus ), a longer pectoral fin (length exceeding the distance from the snout to the posterior margin of preopercle), and the angularity of the dorsal scale rows below the soft dorsal fin (not markedly oblique as in L. griseus ). Lutjanus alexandrei differs from L. apodus in having a red to pale-red body cast and reddish fins instead of a yellowish-pale body with yellow fins, and by having only six narrow pale vertical lines dorsally (sometimes faded) instead of eight wider pale bands as in L. apodus . The number of lateral-line scales, varying from 43 to 48, is also slightly higher than that of L. apodus (40-45), and more similar to that of L. griseus (43-47).

Description. The general morphological features of Lutjanus are presented by Allen (1985) and Anderson (1987) for adults and by Lindeman et al. (2005) for larvae and juveniles, and are not repeated herein. Dorsal rays X, 14; anal rays III, 8; pectoral rays 16 (uppermost rudimentary and unbranched); pelvic rays I, 5; principal caudal rays 9+8; lateral line with 43-48 (45) pored or tubed scales forming a continuous sensory canal between the upper end of gill opening and the caudal-fin base, tubes in lateral line simple, unbranched; branchiostegal rays 7; gill rakers 17-19 (17) total, 5-6 (5) fully developed rakers on the upper limb and 6-9 (8) fully developed plus 3-5 (4) rudimentary rakers on the lower limb; gill membranes separate, free from isthmus; vertebrae 10+14. Body relatively deep, maximum depth 37.3-45.6% (40.3) of SL; snout pointed and long, 27.8-37.8% (33.9) of HL; mouth terminal, large and protractile, with one row of conical teeth in each jaw; a prominently enlarged pair of caniniform teeth on upper jaw, visible when mouth is closed, 3-5 (3) pairs of fanglike pointed conical teeth in lower jaw, vomerine tooth patch anchor-shaped, with a prominent median posterior extension. Morphometric and meristic data are summarized in Tables 1 and 2, respectively.

Origin of dorsal fin slightly posterior to opercular margin; dorsal fin continuous, with only a slight notch between the spinous and soft portions. Caudal fin slightly emarginated; anal fin rounded; pectoral fin pointed and reaching the level of anus, length longer than the distance from tip of snout to posterior edge of preopercle, and 3.0-3.6 (3.5) times in SL. Nostrils small, posterior nostril elongate and at level of pupil, anterior nostril more rounded and located slightly below the level of the posterior one. Preopercle serrate, its lower margin with visible but weak notch and knob. Scales small, ctenoid, not extending dorsally on head above upper margin of orbit nor onto interorbital and internarial space; scales above lateral line (between dorsal-fin origin and lateral line) 6; transverse scale rows between upper edge of opercle and caudal base 37-47 (39); scale rows on cheek 6-7 (7); soft dorsal and anal fins scaled; dorsal scale rows parallel to the longitudinal body axis. Reddish body cast in life (Figure 2), becoming light brown dorsally and pale ventrally in preserved specimens (Figure 1). Body scales with more intense pigmentation on margins, paler in centers. Sides with six pale, thin, vertical lines dorsally. First band on the nape in front of the dorsal fin, fifth under the junction of spiny and soft portion of dorsal fin, and sixth bellow soft dorsal fin. These pale lines are still visible in some preserved specimens but, as observed by Starck (1970) for L. apodus , some specimens may lack these lines. Conspicuous spots (blue in life) are present on the cheek and preopercle, 7-10 of these typically present on snout and ventral portion of head, most below ventral margin of orbit and above superior margin of premaxilla. Median fins red, with more dense pigment on the margins, becoming pale brown in preserved specimens. Live individuals with thin blue distal margins on ventral, anal, and soft dorsal fins (Figure 2) that are not apparent in preserved specimens (Figure 1). Pupils black, iris reddish copper.

In life, early juveniles less than approximately 5 cm typically have reddish or gray bodies and fins. Between 2-3 cm SL, specimens from shaded mangrove areas have dense melanophore rows on body, 6-8 pale vertical bands, and an oblique, black eye stripe (Figure 3). Distal portions of first dorsal and pelvic fins dark red. Caudal, soft dorsal, posterior elements of anal, and pectoral fins transparent. Two thin blue lines from maxilla to posterior margin of opercle. Short, oblique blue line from posterior orbit to opercular margin (Figure3). Specimens from unshaded rocky areas or tidepools can also exhibit pale yellow pigment dorsally and on the distal portions of the soft dorsal and caudal fins. Newly settled individuals from softbottom adjacent to mangroves lack red fin pigment, instead with melanophores concentrated distally on first dorsal, pelvic and anterior anal fins. Remaining fins transparent. Lateral bands on body, and blue and black lines on head begin development by 15 mm.

Etymology. The specific name honors the pioneer Brazilian naturalist Alexandre Rodrigues Ferreira (1756-1815), whose many years of field work in Brazil during the late 18th Century remain underrecognized due to the confiscation of his and others’ collections at Lisbon’s Museu da Ajuda in 1808 (Oliveira & Daly 2001). Ferreira collected many specimens that were ultimately described as new without any reference to his efforts. The common name Brazilian snapper is proposed for L. alexandrei .

Distribution, ecology and behavior. The Brazilian snapper, L. alexandrei is only recorded from the tropical portion of the southwestern Atlantic continental shelf, and has a narrower latitudinal range than other Western Atlantic species of Lutjanus .

It is known from the state of Maranhào (00°52’S) to the southern coast of the state of Bahia (18°0’S), Brazil, in areas under the influence of the west-flowing Equatorial Current (northern Brazil) and the south-flowing Brazil Current (northeastern Brazil).

It is apparently absent from oceanic islands. Additional collections may show an even broader distributional range for this species, as was the case with 48 other poorly known reef-fish species in the southwestern Atlantic (Moura et al. 1999).

Habitats of the Brazilian snapper include coral reefs, rocky shores, coastal lagoons with brackish water, mangroves and other shallow habitats with a mixture of soft- and hard-bottom. Recorded depths range from intertidal (early stages only) to at least 54 m (Feitoza et al. 2005 - identified as L. apodus ). During the day, adults of L. alexandrei were observed on reefs as solitary individuals or in small groups showing restricted activity. Adults can co-occur with L. jocu (see figure on page 40 in MMA 2002, several L. alexandrei were misidentified as L. jocu ). These mixed groups are often composed of large (> 20 cm), probably adult, individuals. Similar to several other Lutjanus species, this species appears to be active predominantly during crepuscular and nocturnal periods. Juveniles smaller than 10 cm SL can be common in mangroves and rocky tidepools, sometimes together with L. jocu juveniles, and may also occur in other shallow habitats. Based on available information, early juvenile stages of L. alexandrei are uncommon or rare in deeper, offshore reef habitats, as in many congeners (Lindeman et al. 1998, Lindeman & DeMaria 2005).

Discussion

The existing literature typically gives the southern distributional limits of L. griseus and L. apodus as southeastern Brazil and northeastern Brazil, respectively (e.g. Menezes & Figueiredo 1980, Uyeno et al. 1983, Allen 1985, Moura & Menezes 2003). All examined lots labeled as Lutjanus griseus and L. apodus in the two major marine fish collections in Brazil (MZUSP and MNRJ) are actually L. alexandrei . We have determined from photographs or voucher materials that all lutjanids commonly identified as L. griseus or L. apodus in field surveys also are L. alexandrei . The same result applies for reef and estuarine fishery catches. The presence of either species in Brazil is highly doubtful given their absence in Brazilian museum collections, field surveys, and fishery landings.

In the southwestern Atlantic there are cases of Caribbean fishes restricted to offshore islands [e.g. Inermia vitatta (Inermiidae) and Haemulon chrysargyreum (Haemulidae)] (Moura & Sazima 2003) or occurring only along restricted portions of the coast [e.g. Chromis scotti (Pomacentridae)] (Moura et al. 1999, Rocha & Rosa 2001). With more surveys, small populations of L. griseus or L. apodus could be definitively recorded from offshore or mainland sites in Brazil. Clearly, the abundant and widespread L. alexandrei is not a product of current hybridization of L. griseus and L. apodus , which, if present in Brazil, must be highly uncommon. Other prominent reef species have also been erroneously recorded from Brazil, including Epinephelus striatus and Lachnolaimus maximus (Serranidae and Labridae) (Sadovy and Eklund 1999, Moura & Sazima 2003). Careful examination of a wide array of seemingly pan-western Atlantic reef species may result in additional changes to long-assumed southern distributions.

Recent discoveries of new species belonging to major coastal fish families in Brazil (referenced in Introduction) suggest a considerable level of isolation between Caribbean and Brazilian populations of coastal fishes, especially those that associate with reefs. Genetic studies also indicate limited gene flow between these two zoogeographic areas, even within groups with a high potential for dispersion such as surgeonfishes (Rocha et al. 2002). Mechanisms of speciation and faunal enrichment in another group of coastal fishes (Scaridae) were recently studied in the Atlantic by Robertson et al (2006), based on mtDNA and nDNA sequences to assess the effects of two major geographic barriers (the>30 million year old Atlantic ocean and the ~11 million year old Amazon -Orinoco outflow). Fluctuations in sea level, climate, and ocean-current dynamics over the past ~10 million years likely produced marked variation in the effectiveness of the Amazon barrier, allowing intermittent dispersal leading to establishment and allopatric speciation. This dynamic Amazon barrier represents a major engine of West Atlantic faunal enrichment that has repeatedly facilitated bi-directional dispersal, allopatric speciation, and remixing of the Caribbean and Brazilian faunas (Moura & Sazima 2003, Rocha 2004, Robertson et al. 2006).

Because of this considerable isolation, caution should be used when management decisions are based on populations from different sides of the Amazon-Orinoco barrier. Moreover, several of the recently discovered species are relatively abundant on coastal habitats such as reefs and mangroves, but were frequently misidentified(see Rocha & Rosa 1999, Moura et al. 2001). This amplifies the need for depositing voucher specimens from ecological and fishery studies in major collections, supports the call for collection building in developing countries, and stresses the need for additional analyses of the numerous systematic problems peculiar to tropical coastal ichthyofaunas.