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Fishery Bulletin 89(2). 1991 



Symphurus tessellatus is one of the most abundant 

 and frequently collected tonguefish species, especially 

 in trawls, from Belize and Honduras south to Venezuela 

 and along the entire coastline of northern South 

 America from the Guianas to about southern Brazil 

 (Meek and Hildebrand 1928, Cervigon 1966, Palacio 

 1974, Carvalho et al. 1968, Menezes and Benvegnu 

 1976). Menezes and Benvegnu (1976) described S. 

 tessellatus as the most abundant tonguefish collected 

 along the Brazilian coast from about 26°49'S to 4°S 

 in northern Brazil. South of 28°S, it appears to be much 

 rarer, and all specimens I examined from Rio Grande 

 do Sul and south are juveniles. The small size of these 

 specimens suggests that adult S. tessellatus may not 

 be regular components of the ichthyofauna of Uruguay 

 and northern Argentina, but that juvenile S. tessellatus 

 either seasonally migrate, or are expatriated by passive 

 transport, into waters along the continental shelf and 

 coastline of Uruguay and northern Argentina. Thus it 

 appears that the region south of Rio Grande do Sul, 

 which comes under periodic influence from the cold 

 Falkland Current, does not harbor large populations 

 of this essentially tropical species so common in 

 warmer waters further north. 



The specimen from the inner continental shelf of 

 Argentina described by Lazzaro (1973) as S. plagiusa 

 and cited in the distribution section for S. plagusia (=S. 

 tessellatus in the present study) by Menezes and Ben- 

 vegnu (1976) is probably not a specimen of S. tessel- 

 latus. Based on the counts and figure provided by Laz- 

 zaro, it more closely matches meristic features and has 

 the general body shape of S. trewavasae. 



Bathymetric distribution Throughout its range, 

 juvenile S. tessellatus are commonly taken by beach 

 seine in nearshore habitats, and larger adults are fre- 

 quently captured by trawl in deeper waters. Individuals 

 have been collected from a depth range of 1-86 m 

 (Table 11). There is an ontogenetic migration offshore. 

 Juveniles occur commonly in medium- to high-salinity 

 regions of estuaries and in high-salinity, soft-bottom 

 habitats in nearshore mudflats. Adults generally range 

 into deeper water, although a few large fishes I exam- 

 ined were taken in relatively shallow water. Most of 

 the 349 S. tessellatus examined in this study were col- 

 lected between 1 and 70 m (Table 11), but the majority 

 of captures, and the center of abundance for this 

 species, occurs in depths of l-50m (81% of the indi- 

 viduals in this study). The deepest captures are for a 

 single specimen taken at 86 m and 21 individuals at 

 73 m. The majority of shallow-water captures were 

 specimens smaller than 130mm SL. 



Interestingly, Menezes and Benvegnu (1976) re- 

 ported that in southern Brazil, S. tessellatus (misiden- 

 tified as S. plagusia) occurs only in shallow water 



(< 12 m), though it is known to occur deeper in northern 

 Brazil. They suggested that the presence of S. jenynsi 

 off southern Brazil, which generally occurs on the con- 

 tinental shelf at depths greater than 12 m, somehow 

 prevented the occurrence of S. tessellatus at these 

 depths. Another explanation is that S. tessellatus is 

 primarily a tropical species reaching its southern limit 

 of distribution in southern Brazil south of Rio de 

 Janeiro. Its bathymetric distribution in these waters 

 may be limited not by competitive interaction from S. 

 jenynsi; rather, the offshore distribution of S. tessella- 

 tus may be restricted by cooler water temperatures on 

 the shelf. The appearance of S. jenynsi, a temperate- 

 water species (Menezes and Benvegnu 1976), in these 

 regions indicates that temperature may strongly in- 

 fluence the offshore distribution of S. tessellatus in 

 southern Brazil. 



Throughout its range to at least Rio de Janeiro, juve- 

 nile S. tessellatus occur in similar habitats and are often 

 collected with a complete size range of S. plagusia. In 

 the Caribbean, juvenile S. tessellatus are also taken 

 with a complete size range of S. caribbeanus. Along 

 the northeastern coast of South America from Surinam 

 to eastern Brazil, large adults of this species are col- 

 lected in deeper areas with a wide size range of speci- 

 mens of S. oculellus and S. diomedeanus. 



Remarks Comments regarding the nomenclatorial 

 history of this species were reviewed under the "Re- 

 marks" section in the account of S. plagusia. All 

 authors since Kaup (1858) have considered S. tessella- 

 tus and S. plagusia as conspecific. However, results of 

 this study indicate that S. plagusia and S. tessellatus 

 are both valid species. 



The original description of Plagusia tessellata by 

 Quoy and Gaimard (1824) provides sufficient informa- 

 tion to clearly identify their specimen. This is the 

 earliest name applied to a tonguefish collected from the 

 southern Brazil region and, therefore, has priority over 

 Plagusia brasiliensis Agassiz, in Spix and Agassiz 

 1831. Plagusia brasiliensis was collected at "Bahia," 

 Brazil. The type specimen was thought to have been 

 destroyed during the Second World War (Whitehead 

 and Myers 1971). However, in two recent publications 

 concerning authorship and existence of type specimens 

 described in Spix and Agassiz's "Brazilian Fishes" 

 (1829-31), Kottelat (1984) listed a specimen (MHNN 

 691) first as the holotype, and later (Kottelat 1988) as 

 a possible syntype of P. brasiliensis, thus indicating 

 the existence of at least one specimen from the original 

 account of this nominal species. My examination of this 

 specimen reveals that meristic features lie completely 

 within the range of counts typical for S. tessellatus (ID 

 pattern 1-4-3, caudal fin rays 12, dorsal fin rays 99, anal 

 fin rays 83, total vertebrae 53, longitudinal scales 90, 



