Names and classification of fishes 97

chapter six

Names and classification of fishes

Fish species often (but not always) have local names, but all formally described species have a scientific or Latin name that is used by the international scientific community. Suriname has many languages and fish species with a country-wide distribution thus may have many local names. On the other hand, fish species that are endemic to (the upper reaches of) a single river system may have a single local name of restricted use or no local name at all (if they are small and little known). Sranan Tongo (S) is a creole language developed by negro slaves and probably the most commonly spoken language in Suriname (besides the official Dutch language). In the spelling of Sranan Tongo this book follows Stichting Volkslectuur Suriname (1995, 3rd ed.). The Carib languages are spoken by a num- ber of indigenous Amerindian peoples in Suriname (e.g. Kalina-caribs, Tiriyo, Wayana) and many local names of plants and are derived from a Carib language. The six maroon peoples of Suriname, descendents of escaped slaves, have their own languages, the best known being Saramaka or Saramacca. In the Coastal Plain, East Indian and Javanese (Indonesia) descendants of contract laborers brought in after the abolition of slavery, speak Hindi and Javanese, respectively. All described species have a single valid scientific name, although this valid name often has many synonyms (for updated valid fish names and synonyms see W. Eschmeyer & Fricke, 2011). The binomial, scientific name, as first proposed by Linnaeus in 1753, is composed of two parts, the first of these is the , as in Homo, and the second is the species, as in sapiens. For example, the redeye pira- nha or piren (S) is rhombeus. The generic name Serrasalmus pertains to a group of closely related species that share a number of common features related to general shape, of teeth, scalation, fin-ray counts and so on. The specific name rhombeus applies only to a single entity that is distinguished from its relatives by a unique combination of characters, often including color/pigmen- tation pattern. One can speak of the genus Serrasalmus, but not of the species rhombeus; the specific name is always used in combination with the generic name (thus it is the species Serrasalmus rhombeus). The ‘Latin’ or ‘scientific’ names of species are always written in italics; the generic name always begins with an upper-case letter and the specific name is always lower case even when it is derived from a proper name (e.g. when constructed after people or places, as in surinamensis). When it is obvious which genus we are talking about it is permis- sible to present the generic name simply as an initial, and so we can say S. rhombeus. But this we should do only if it is absolutely clear that the ‘S’ stands for Serrasalmus. After all many different genera of all kinds have names that begin with ‘S’ and many share the same specific qualifier. 98 chapter six

Linnaeus also proposed a formal hierarchical system of classification. The binomial name already implies this: the small category of the ‘species’ nests within the broader category ‘genus’. Related genera (plural of genus) are then grouped together in a family, whose spelling always ends in -idea. Worldwide there are approximately 515 families of fishes with living species (Nelson 2006); 64 are represented in fresh and brackish waters of Suriname (Table 2). Large families such as the Characidae and Loricariidae can be subdivided in subfamilies whose spelling ends in -inae. A group of similar families is classified in one of the 62 orders of fishes whose spelling ends in -iformes. The highest levels of classification pertain to class and phylum. The Class Chondrichthyes contains sharks and rays (including the freshwater sting rays or spari (S) in the family Potamotrygonidae) and the Class Osteichthyes contains the vast majority of bony fishes (Nelson, 2006). All fishes belong to the Phylum Chordata, as do other higher animals including amphibians, reptiles, birds and mammals. The classification of the redeye can therefore be summarized as fol- lows: Phylum Chordata Class Osteichthyes Order Family Chara­cidae Subfamily Serrasalminae Genus Serrasalmus Species S. rhombeus Characters used to separate species, and often genera, include external (mor- phological) features such as the number of fin rays, size and number of scales, ratio of various body proportions and color patterns. Internal structures, particu- larly those pertaining to skeletal elements, are often indicative of relationships at levels of higher classification (family, order, class). A good example are the Weberian ossicles that characterize otophysan fishes (orders Characiformes, Siluriformes, Gymnotiformes and Cypriniformes). In recent years, genetic (molec- ular) methodology (electrophoresis and DNA analysis) has become more sophis- ticated and widely used as a supplemental tool for elucidating relationships or recognizing distinct species (see for example Covain et al., 2012). Why do the scientific names of fishes sometimes change? There are four pri- mary reasons that systematists change names of organisms: (1) ‘splitting’ what was considered to be a single species into two (or more) (see for example Reis et al., 2005 for splitting of katrina kwikwi Megalechis thoracata); (2) ‘lumping’ two species that were considered distinct into one; (3) changes in classification (e.g. a species is hypothesized to belong in a different genus); and (4) an earlier name is discovered and becomes the valid name by the (the is the senior ; other, later names are junior synonyms). Many fish species previously unknown to science have been discovered in fresh waters of Suriname over the past few decades and this is a process that con- tinues to this day. When a ‘new’ (i.e. not formally described) fish is discovered it is