UvA-DARE (Digital Academic Repository) From the Amazonriver to the Amazon molly and back again Poeser, F.N. Publication date 2003 Link to publication Citation for published version (APA): Poeser, F. N. (2003). From the Amazonriver to the Amazon molly and back again. IBED, Universiteit van Amsterdam. General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl) Download date:24 Sep 2021 From the Amazon river to the Amazon molly and back again: Introduction iii Pre-Hennigian taxonomy of Poecilia In this introduction, I summarize the taxonomy of Poecilia and its allies. This is done in two chronological arranged sections. A third section is moved to Appendix 1. In Appendix 1, I summarize the taxa recorded by Eschmeyer (1990) as former and present synonyms of Poecilia in alphabetic order. This list is annotated and some taxa are added to provide an overview of relevant the taxa. The pre-Hennigian taxonomie history of Poecilia originates from the description of P. vivipara to culminate in the revision of Rosen and Bailey (1963) and its direct consequences. The revision of Rosen and Bailey is considered the standard of present day poeciliid taxonomy (cf. Parenti and Rauchenberger, 1989), also for Poecilia. Within Poecilia, there is a large species complex of morphological similar taxa that is referred to as the P. sphenops complex. The species of this group (Schultz and Miller, 1971; Menzel and Darnell, 1973, Miller, 1975, 1983, 1994; Poeser, 1992, 1995, 1998, 2002a, in press) have been considered as variations of one single, widely dispersed species, viz., P. sphenops (cf. Garman, 1895; Regan, 1908, 1913; Hubbs, 1926a; Rosen and Bailey, 1963). A great deal of my own work has concentrated on characterizing the P. sphenops complex. Besides the P. sphenops species group, commonly referred to as the "mollies", there are the "guppies", i.e., P. reticulata and similar species. The taxonomie details are beyond the scope of this introduction, it is treated in detail in Chapter 11; here it suffices to mention that the taxonomy of Poecilia stretches beyond "mollies and guppies." The taxonomie history is divided into two parts, comprising the 19th and 20th century respectively, based on prevailing taxonomical insights. Whereas the taxonomists in the 19th century were primary concerned about general appearance, fin ray counts, dental structures and intestines, the 20th century taxonomists mainly focussed on the structures in the modified anal fin in the male, i.e., the gonopodium. The latter approach led to a multiplicity of taxa, in which every gonopodial ray represented information for accepting or rejecting genera. For example, after assessing Regan's (1913) illustration of the gonopodium of P. vivipara (Fig. 6C), Hubbs (1924a) described Neopoecilia holacanthus, providing a much more detailed illustration (Fig. 7A). However, after examining material of P. vivipara, Hubbs (1926a) realized he had pictured the same species, only with a greater accuracy. The revision of Rosen and Bailey (1963), in which the gonopodia had very little influence on infrageneric classification, resulted in serious lumping. The taxonomy subsequent to Rosen and Bailey is characterized by attempts to find a balance between splitting and lumping. 19th Century taxonomy Bloch and Schneider (1801) The genus Poecilia Bloch and Schneider, 1801 was described as a group of five species, viz., P. vivipara from Surinam, P. coenicola from Carolina (USA), P.fasciata and P. majalis from New York (USA), and P.fusca from 'Pacific Islands'. Poecilia vivipara was figured iv From the Amazon river to the Amazon molly and back again: Introduction with a forked tail (Fig. 1A), together with an opened body to give evidence of its viviparity (Fig. IB). Specific details from its description were (translated from Latin; B. = gill rakers, P. = pelvic fin rays, V. = ventral fin rays, A. = anal fin rays, C. = caudal fin rays, D. = dorsal fin rays): "compressed body, head with scales, depressed on top, broad, mouth blunt, lateral line near to back, broad caudal fin, split, anus near head. B. 6, P. 12, V. 6, A. 7, C. 20, D. 7." Figure 1 (after Bloch and Schneider, 1801). A. Holotype of Poecilia vivipara B. Holotype ventrally opened to show developing eggs LeSueur(1821) Mollienesia latipinna LeSueur, 1821, from which the vernacular name 'molly' originated, was described before the position and modifications of the anal fin were recognized as sexual dimorphic characters (Fig. 2A). Mollienesia differed from another form LeSueur recognized, viz., Poecilia multilineata LeSueur, 1821, mainly in the relative position of the anal fin. Subsequent to the recognition of sexual dimorphism in poeciliid fishes, the latter taxon (Fig. 2B) proved to be the female sex of M. latipinna. Muller and Troschel (1844) In the 19th century several nominal taxa were subsequently described, in which the males were assigned to new genera and the females were recognized as Poecilia. For example, from collections of live-bearing fish sent from Mexico, the females (referred to as "genus Poecilia") were sent to Dr. Valenciennes (see below), whereas a male was described as Molinesia (sic) fasciata Muller and Troschel, 1844. The holotype of M.fasciata was switched From the Amazon river to the Amazon molly and back again: Introduction v with the holotype of M. surinamensis Muller and Troschel, 1844 (cf. Paepke and Meyer, 1995), also a male specimen. Both M.fasciata and M. surinamensis (both males) had specific names that were pre-occupied by a species in Poecilia, respectively P. fasciata and P. surinamensis (both supposedly females). In this particular (and peculiar) case, the authors seem to have willingly transferred two species of Poecilia to Mollienesia after the other gender was discovered {Mollienesia is from Mars, Poecilia is from Venus). However, since Muller and Troschel's (1844) account is very sketchy, we will forever guess their reasons. Figure 2 (after LeSueur, 1821). A. Holotype of Mollienesia latipinna B. Holotype of Poecilia multiline-ata Rosen and Bailey (1963) wrote: "Molinesia fasciata Muller and Troschel, 1844, when referred to Poecilia by Eigenmann (1893, p. 57), became a junior secondary homonym of Poecilia fasciata Bloch and Schneider, a synonym of Fundulus heteroclitus (Linnaeus). Had this homonymy been noted and Molinesia fasciata Muller and Troschel rejected prior to 1960, that name would now be unavailable ... Because apparently no such action was taken, we vi From the Amazon river to the Amazon molly and back again: Introduction assume that the name is nomenclaturally available ... however, the original description is so sketchy ... We therefore regard Molinesia fasciata as unidentifiable unless the type material be located." Figure 3 (after Cuvier and Valenciennes, 1846). Holotype of Poecilia sphenops The type material of both Muller and Troschel's species was located and excellently redescribed by Paepke and Meyer (1995). In an account of historical documents deposited at the archives of the Berlin Museum, they recorded the collection site where a Mr. Deppe collected live-bearing fish (referred to as "genus Poecilia") from rivers in the Central Veracruz State (Rio Misantla at Misantla and Rio Tacoluta [Rio Tecolutla], see Paepke and Meyer, 1995). At about the same time Mr. Deppe collected his material in Mexico, a Mr. Steglich collected live-bearers in Surinam, which he sent to Berlin. In their discussion, Paepke and Meyer related to more mix-ups of Deppe's material, and concluded that the holotype of Molinesia fasciata must have been switched with the holotype of M. surinamensis. They illustrated and accurately described both holotypes, showing that the fish registered as "ZMB 3472, holotype of Molinesia fasciata" is indeed a specimen of P. vivipara. Also the specimen in ZMB 3473, "Molinesia surinamensis," is without doubt the same as P. sphenops (inferred from meristic evidence, dental structures and type locality Veracruz). Paepke and Meyer (1995) derived no nomenclatural consequences from this mix-up. Molinesia fasciata was assigned to the synonymy of P. vivipara, and M. surinamensis, assigned to the synonymy of P. sphenops, would become P. surinamensis, a junior homonym of P. surinamensis Humboldt and Valenciennes, 1821. In the latter case, the name P. sphenops is also retained. I disagree with this latter conclusion. Allocation of P. surinamensis to the synonymy of P. sphenops would imply the occurrence of P. sphenops in Surinam, which is an incorrect notion (as is the occurrence of P. vivipara in the Veracruz district, see Chapter 11). The mistake made by switching the holotypes of these species cannot replace the range of both species, as currently known to science. I therefore propose to recognize the exchange of holotypes and acknowledge the original description of M. fasciata (and of M. surinamensis) as valid. From the Amazon river to the Amazon molly and back again: Introduction vii Molinesia surinamensis remains a synonym of P. vivipara, whereas M. fasciata has priority over P. sphenops (as noted by Rosen and Bailey, 1963). Generic allocation to Poecilia would render its name as P. fasciata (Muller and Troschel, 1844), which is, however, pre-occupied by a synonym of Fundulus heteroclitus (Linnaeus, 1766).