Diversity and Conservation of Seasonal

Zoosyst. Evol. 94 (2) 2018, 495–504 | DOI 10.3897/zse.94.29718 Diversity and conservation of seasonal killifishes of the Hypsolebias fulminantis complex from a Caatinga semiarid upland plateau, São Francisco River basin, northeastern Brazil (Cyprinodontiformes, Aplocheilidae) Wilson J.E.M. Costa1, Pedro F. Amorim1, José Leonardo O. Mattos1 1 Laboratory of Systematics and Evolution of Teleost Fishes, Institute of Biology, Federal University of Rio de Janeiro, Caixa Postal 68049, CEP 21941-971, Rio de Janeiro, Brazil http://zoobank.org/6ED9D33E-EB4B-4E84-BBFB-B0E1BCF6A4DE Corresponding author: Wilson J.E.M. Costa ([email protected]) Abstract Received 12 September 2018 A high concentration of endemic species of seasonal killifishes has been recorded for a Accepted 4 October 2018 small area encompassing the highland plateaus associated with the upper section of the Published 15 November 2018 Carnaúba de Dentro River drainage and adjacent drainages of the middle section of the São Francisco River basin, northeastern Brazil. The present study is primarily directed to Academic editor: the taxonomy of the H. fulminantis species complex in this region, and describes habitat Peter Bartsch decline and extirpation of natural killifish populations recorded in field studies between 1993 and 2017. Both morphological characters and molecular species delimitation meth- Key Words ods using single-locus models (GMYC and bPTP) support recognition of two closely related endemic species, H. fulminantis and H. splendissimus Costa, sp. n. The new spe- Biodiversity cies is distinguished from other congeners of the H. fulminantis complex by having a red species delimitation pectoral fin in males, well-developed filamentous rays on the tips of the dorsal and anal systematics fins in adult males, and the second proximal radial of the dorsal fin between the neural taxonomy. spines of the 8th and 9th vertebrae in males. Most recent field inventories indicated possible local extinction of populations of H. fulminantis and H. splendissimus in the studied area, but additional field studies should be made in other parts of the upper Carnaíba de Dentro River basin to evaluate the current conservation status of these species. Introduction Caatinga are uniquely found in temporary pools formed during the rainy seasons, a specific kind of aquatic hab- In the last three decades, field studies of cynolebiine kil- itat that was not sampled by ichthyologists until the first lifishes in temporary pools of the Caatinga, a semi-arid studies of seasonal killifishes in the region (e.g., Costa phytogeographical province of northeastern Brazil, have and Brasil 1990, 1991, 1993). The life cycles of seasonal continuously revealed spectacular species diversity (e.g., killifish are conditioned by irregular rainy seasons in the Costa 2001, 2007, 2014; Costa et al. 2012, 2018a). Over region mostly occurring between November and May, as 50 valid species of the two killifish genera occurring in well as by long dry periods, sometimes extending over a the Caatinga, Cynolebias Steindachner, 1876 and Hyp- year, when species survive in resistant eggs buried in the solebias Costa, 2006, are endemic to the main river ba- pool substrate (Wourms 1972; Costa 1995). sins of the region, with a greater concentration of spe- In spite of the great morphological diversity exhibited cies in the São Francisco River basin (e.g., Costa et al. by different endemic lineages of seasonal killifishes, sev- 2018b). Like other African and South American season- eral cryptic species have been recently recognised in the al aplocheiloid killifishes, cynolebiine killifishes of the Caatinga using molecular species delimitation analyses Copyright Wilson J.E.M. Costa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 496 Costa, W.J.E.M. et al..: Diversity and conservation of seasonal killifishes... (e.g., Costa et al. 2012, 2014, 2018a). These studies have the past, H. fulminantis was frequently sampled around identified distinct cryptic species inhabiting the same the town of Guanambi, in pools situated in the northeast- drainage of the São Francisco River basin, showing that ern and southern parts of the town’s periphery, at altitudes most seasonal killifish species exhibit a very restricted between about 525 and 555 m asl. However, during field distribution range (Costa et al. 2012, 2018a). However, studies in January 2010, after a severe environmental while field studies have been conducted to estimate killi- change in the region caused by the expansion of the Gua- fish species diversity in the region, drastic anthropic mod- nambi urban area, it was noted that all temporary pools ifications in seasonal killifish habitats of some Caatinga sampled in previous years, inhabited by H. fulminantis, areas have caused extinction of several populations (Cos- had been extirpated. On the other hand, new populations ta 2002, 2017; Costa et al. 2012, 2018a). of seasonal killifishes were found just west from Guan- An uncommonly high concentration of endemic spe- ambi, including a population with specimens similar to H. cies of seasonal killifishes has been recorded for a small fulminantis but exhibiting some distinct morphological area encompassing the highland plateaus associated with traits, suggesting that they may be a new species, which the upper sections of the Carnaúba de Dentro and the is here supported by molecular species delimitation meth- Verde Pequeno river drainages, in the middle section of ods. The objectives of this paper are to describe the new the São Francisco River basin (Costa and Brasil 1993; species and to provide a report on distribution and conser- Costa et al. 1996; Costa and Nielsen 2004; Costa 2006a, vation of species of the H. fulminantis complex in the up- 2014, 2017). This area is characterised by a series of per Carnaíba de Dentro River basin based on field studies plains located at slightly different altitudes, between 500 made between February 1993 and March 2017. and 630 m above sea level (asl), separated from each other by an undulating relief and drained by temporary rivers and streams. Among the eight species reported for this Material and methods area, two species, Hypsolebias fulminantis (Costa & Bra- sil, 1993) and Hypsolebias carlettoi (Costa & Nielsen, Specimens 2004) are members of a clade endemic to the Caatinga, which was named as J’-clade by Costa (2006b) and then Methods for fish capture, euthanasia, fixation, and preser- diagnosed by the presence of a distinctive anteromedial vation in collections follow methods described by Costa process on the second hypobranchial, directed toward the et al. (2018a) for other seasonal killifishes of the Caatin- second basibranchial (Costa 2006b: fig. 17c). Species of ga, which were approved by CEUA-CCS-UFRJ (Ethics this clade are also unique among congeners by the high- Committee for Animal Use of Federal University of Rio ly contrasting colouration of the unpaired fins in males, de Janeiro; permit number: 065/18). Collections were consisting of intense bright blue marks over a red back- made with permits provided by ICMBio (Instituto Chico ground, and the presence of intense red pigmentation on Mendes de Conservação da Biodiversidade; permit num- the trunk in males. The J’-clade also includes H. shiba- bers: 34270-4, 20618-1, 57099-1). Preserved specimens ttai Nielsen, Martins, Araujo & Suzart, 2014, a species listed in this paper are deposited in the ichthyological closely related to H. fulminantis, and a group known as collections of: Museu de Zoologia, Universidade de São the Hypsolebias magnificus species complex that com- Paulo, São Paulo (MZUSP), and Instituto de Biologia, prises H. gardneri Costa, 2018, H. hamadryades Costa, Universidade Federal do Rio de Janeiro, Rio de Janeiro 2018, H. harmonicus (Costa, 2010), H. magnificus(Costa (UFRJ). In lists of material, the abbreviation C&S indi- & Brasil, 1991), and H. picturatus (Costa, 2000) (Costa cates specimens prepared for osteological analysis and 2007, 2010; Nielsen et al. 2014; Costa et al. 2018a). Hyp- preserved in glycerine (see below), and DNA indicates solebias fulminantis and H. shibattai form a consistent specimens fixed and preserved in 98 % ethanol. List of subclade, herein named the H. fulminantis species com- specimens used in the molecular analysis and their re- plex, easily diagnosed by the presence of narrow metallic spective GenBank accession numbers appears in Table 1. blue lines parallel to the fin rays on all unpaired fins, in Comparative material is listed in Costa (2007, 2010) and contrast to metallic blue dots or transverse blue stripes Costa et al. (2018a). on the unpaired fins in other species of the group (Costa Morphological data 2007). In addition, in species of this complex the oper- cular region and the anteroventral portion of the flank is Descriptions of colouration in living fish were based on intense yellow ochre in males, instead of pale golden as photographs of both sides of individuals. Photographs in other congeners of the J’-clade. were taken in small aquaria about 24 hours or less af- Hypsolebias fulminantis since its description in 1993, ter collections. Additional direct observations were made has become a popular aquarium fish due to the colour- with fish in small transparent plastic bottles just after col- ation exhibited by males. It was often collected by aq- lection. Measurements and counts follow Costa (1988). uarists and amateur ichthyologists and consequently Measurements are presented as percentages of standard appears in numerous aquarium fish websites. However, length (SL), except for those related to head morphology, field studies in the region have shown a sharp decline in which are expressed as percentages of head length. Mea- natural populations (person. observation by WJEMC). In surements were made only in specimens fixed in 10 % zse.pensoft.net Zoosyst. Evol. 94 (2) 2018, 495–504 497 Table 1.

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