Opistognathus aff. aurifrons Jordan & Thompson, 1905

Smith-Vaniz, William F., Tornabene, Luke & Macieira, Raphael M., 2018, Review of Brazilian jawfishes of the genus Opistognathus with descriptions of two new species (Teleostei, Opistognathidae), ZooKeys 794, pp. 95-133 : 114-118

Opistognathus aff. aurifrons Jordan & Thompson, 1905 Figures 4D, 5D, 18, 19, 20, 21; Tables 1, 2

Opistognathus aurifrons Jordan & Thompson, 1905: 252, fig. 4 (original description; Garden key, Dry Tortugas, Florida); Moura et al. 1999: 517 (Brazilian occurrence); Pereira-Filho et al. 2015: 69-70 (Listed, Fernando de Noronha Archipelago); Stocco and Joyeux 2015: 6 (ichthyoplankton, Trindade Island).

Opistognathus sp. Rocha and Rosa 2001: 990 (listed; Manuel Luiz Marine State Park, Brazil); Gasparini and Floeter 2001: 1644 (listed; Trindade Island); Rocha 2002: 477, unnumbered color fig. (Parcel Manuel Luiz, Brazil); Menezes et al., 2003: 78; Moura and Sazima 2000: 482 (listed); Sampaio and Nottingham 2008: 171 (abbreviated description).

Opistognathus sp. 1 Carvalho-Filho 1999: 193, color fig. 185; Pinheiro et al. 2018, Southwestern Atlantic (SWA) Endemic reef fishes - Annotated Checklist: 29-30, color fig. 19 (Fernando de Noronha Archipelago).

Opistognathus sp. 2 Smith-Vaniz 1997: 1096 (in identification key); Simon et al. 2013a: 2120 (listed); Pinheiro et al. 2018, Southwestern Atlantic (SWA) Endemic reef fishes - Annotated Checklist: 30-31, color fig. 20.

Opistognathus aff. aurifrons Jordan & Thompson: Feitoza et al. 2005: 732 (Brazilian Province in 35-54 m); Simon et al. 2013b: 63 (listed); Pinheiro et al. 2015: 15, color fig. S.37 (Trinidade Island and Dogaressa Seamount).

Abbreviated description (Brazilian specimens only).

A species of Opistognathus with the following combination of characters: anterior nostril a short tube without a cirrus on posterior rim; posterior end of maxilla rigid, not produced as a thin flexible lamina; supramaxilla present; dorsal-fin spines thin, flexible, usually curved distally, and tips without pale, slightly swollen tabs; subopercle without a broad, fan-like flap; most of nape without sensory pores (Figure 4D); dorsal fin XI, 14-15, with 6-11 anterior rays unbranched distally; anal fin III, 14-15, with 7-10 anterior rays unbranched; outermost segmented pelvic-fin ray tightly bound to adjacent ray and interradial membrane not incised distally; scales in longitudinal series 66-76; vertebrae 10+17; supraneurals absent; gill rakers 15 –20+26–32=41– 51; dentary with large lateral canines (Figure 5D). Life color of adults of the two different color morphs as in Figs 18-20 and discussed below in Remarks.

Distribution.

As provisionally recognized, this species is known only from the Brazilian Province including continental localities from the State of Maranhão (0°53'S, 44°17'W) south to Armação de Búzios (22°45'S, 41°59'W) in the State of Rio de Janeiro and oceanic sites of the Vitória-Trindade Seamounts Chain and Fernando de Noronha Archipelago (Figure 6). It is common in coastal regions, in depths of 10-30 meters, and in oceanic sites of 10-65 meters, associated with rubble and sand bottoms, near coral reefs and rocky areas. Its behavior and life history are similar of that of the Caribbean O. aurifrons ( Colin 1971; Colin 1973). In this species the burrows are constructed on sandy or rubble bottoms, near reefs, using small stones, shell or coral fragments. They feed on zooplankton while hovering at a small distance over the substrate during quick incursions and generally retreat tail first into the burrow.

Material examined.

33 specimens (30.4-73.7 mm SL) all from Brazilian Province. Mainland localities: ANSP 188905 (2, 35.4-63.8 C&S), Naufrágio Bellucia (shipwreck), off Guarapari, Espírito Santo, 20°40'S, 40°21'W, 24.6 m, 29 August 2008, A. Carvalho-Filho, R.M. Macieira and C.R. Pimental; CAS 238006 (3, 53.2-57.5), Ilha Escalvada, Guarapari, Espírito Santo, 20°42'S, 40°24'W, 30 March 2012, L.A. Rocha; CAS 238007 (4, 58.8-70.3), Ilha Escalvada, Guarapari, Espírito Santo, 20°42'S, 40°24'W, 15 February 2012, L.A. Rocha; CIUFES 0795 (4, 24.0-66.9), Naufrágio Bellucia (shipwreck), off Guarapari, Espírito Santo, 20°40'S, 40°21'W, 27.0 m, 11 March 2008, J.-C. Joyeux, R.M. Macieira and V.C. Brilhante; CIUFES 1450 (2, 57.1-73.7 C&S), Ilhas Rasas, Guarapari, Espírito Santo, 20°40'S, 40°22'W, 15 m, 14 August 1999, J.L. Gasparini; MZUSP 44937 (1, 52.4), Ilhas Rasas, Guarapari, Espírito Santo, 20°40'S, 40°21'W, January 1992, J.L. Gasparini; MZUSP 46191 (1, 67.5), male, Cabo Frio, Rio de Janeiro, 22°53'S, 42°00'W, March 1991, A. Carval ho-Filho; MZUSP 46541 (1, 61.8), gravid female, Vitória, Espírito Santo, 20°19'S, 40°21'W, December 1990, A. Carvalho-Filho; MZUSP 52271 (2, 35.0-42.8), Ilha Sueste, Abrolhos Archipelago, 17°58'S, 38°41'W, 11 January 1997, I. Sazima, C. Sazima, J.L. Gasparini and R.L. Moura; MZUSP 52453 (1, 46.9) and UF 191039 (3, 30.4-51.6), Ilhas Rasas, Guarapari, Espírito Santo, 20°40'S, 40°22'W, 22 April 1992, D.A. Jório; ZUEC 3105 (1, 72.6), Ilhas Rasas, Guarapari, Espírito Santo, 20°40'S, 40°22'W, 18 m, 1 June 1996, D.A. Jório; ZUEC 2739 (1, 61.6), gravid female, Ilha Escalvada, Guarapari, Espírito Santo, 20°42'S, 40°24'W, 16 m, July 1995, D.A. Jório and J.L. Gasparini; UFPB 4047 (5, 52.4-67.5), Três Ilhas Archipelago, Guarapari, Espírito Santo, 20°36'S, 40°22'W, 1 December 1997, J.L. Gasparini. Fernando de Noronha Archipelago: CIUFES 2550 (1, 58.4) and CIUFES 2551 (1, 69.2), Cabeço Submarino, 03°52'S, 32°25'W, 19.6 m, 8 April 2013, R.M. Macieira and T. Simon.

Remarks.

Brazilian specimens of Opistognathus aff. aurifrons (n=28) differ from Caribbean O. aurifrons (n=292) in consistently having 17 vs. 16 caudal vertebrae. Bra zilian fish are represented by two allopatric and slightly different genetic populations (see discussion below in "Phylogenetic relationships of western Atlantic Opistognathus "). Mainland and Vitória-Trindade Seamounts Chain specimens have long pelvic fins that when depressed extend at least to the anal-fin origin (25.7-38.2% SL, mean 30.4%, in 22 specimens 30.4-74.8 mm SL) and in fresh adult specimens the top of the head is yellow, bordered posteriorly by a narrow blue band extending from slightly behind the eye to upper jaw and across the nape; remainder of the head and body greenish-yellow to bluish-yellow (Figures 18-19). Populations from the Fernando de Noronha Archipelago differ in having short pelvic fins that do not extend to the anal-fin origin (20.1-20.7% SL in 2 specimens 58.4-69.2 mm SL) and in fresh adults the head is pale tan-yellow, the body is pale grey-blue, and both are uniformly colored (Figure 20). To further complicate the situation, uncollected juveniles from Fernando de Noronha (Figure 21) and Bonaire (Figure 22) have identical life coloration consisting primarily of a white head crossed by diagonal brown-orange stripe about width of pupil extending from chin, through eye and across nape; body and fins pale grey. In preservation, adults from Tobago (USNM 317005) have the same head color pattern and long pelvic fins as those of the Brazilian mainland population but differ in having 16 caudal vertebrae. Unfortunately, life coloration was unrecorded and tissue samples were not obtained. A color photograph taken by Les Wilkes of a "Bluebar jawfish" from St. Vincent, Lesser Antilles (13°15'N, 61°12'W) also looks like mainland Brazilian adults. Overall, there are morphological characters that collectively differentiate the two Brazilian clades from the Caribbean haplotypes (i.e., vertebral counts) and from each other (i.e., pelvic fin length, but note the low sample size), but we know of no consistent phenotypic characters that differentiate the two Caribbean haplotypes from each other. The type locality for O. aurifrons is Dry Tortugas, Florida, making it likely that if the main groups here do indeed represent distinct species, the group containing specimens from Florida (green in Figure 24) represents the true O. aurifrons and the others new species. However, we refrain from making taxonomic changes pending a more thorough analysis comparing multiple genetic loci, and live coloration/morphology of vouchered specimens.

Depending on the locality, adults of Caribbean Opistognathus aurifrons may have relatively short or long pelvic fins, color patterns not found in Brazilian populations or that duplicate them.

Conservation.

The conservation status of Brazilian populations of this species has been assessed by the Ministério do Meio Ambiente/Instituto Chico Mendes de Conservação de Biodiversidade (MMA/ICMBio - Brazil) and listed as Least Concern.