Re-description of Laetacara curviceps ( Teleostei : Cichlidae : Cichlinae )

Laetacara KULLANDER, 1986 is a South American cichlid fi sh genus currently comprising six valid species: Laetacara fl avilabris (COPE, 1870) (the type species of Laetacara), L. thayeri (STEINDACHNER, 1875), L. dor sigera (HECKEL, 1840), L. curviceps (AHL, 1924), L. fulvipinnis STAECK & SCHINDLER, 2007 and L. araguaiae OTTONI & COSTA, 2009. KULLANDER (1986) redescribed L. fl avilabris and L. thayeri in his book about the cichlid fi shes of Peru and synonymized Acara freniferus COPE, 1872 (which was a valid taxon within the “Aequidens” dorsiger group) to L. fl avilabris, because its description was based on specimens not distinguisable from L. fl avilabris. Populations of Laetacara dorsigera from Argentina were described by CASCIOTTA (1998), and more recently OTTONI & COSTA (2009) re-described L. dorsigera based on specimens from Brazil. Laetacara dorsigera is distributed in the rio Guaporé and the lower rio Mamoré drainages of the Amazon basin and in the rio Paraguay and the middle rio Paraná of the rio Paraná basin in Argentina, Brazil and Paraguay (OTTONI & COSTA, 2009). However, Laetacara curviceps is taxonomically not well known. This species was introduced to the German aquarium trade in 1909 as “Acara thayeri”. Later it was recognized as a new species and was described by AHL (1924), the former curator of Herpetology in the Berlin Museum, as Acara curviceps based on specimens obtained from the tropical aquarium-fi sh trade from “Amazonenstrom”. In this paper we present a re-description of Laetacara curviceps based both on the types and additional material from Município Parintins and Município de Óbidos, rio Amazon basin. Re-description of Laetacara curviceps (Teleostei: Cichlidae: Cichlinae)


Introduction
Laetacara KULLANDER, 1986 is a South American cichlid fi sh genus currently comprising six valid species: Laetacara fl avilabris (COPE, 1870) (the type species of Laetacara), L. thayeri (STEINDACHNER, 1875), L. dor sigera (HECKEL, 1840), L. curviceps (AHL, 1924), L. fulvipinnis STAECK & SCHINDLER, 2007and L. araguaiae OTTONI & COSTA, 2009. KULLANDER (1986) redescribed L. fl avilabris and L. thayeri in his book about the cichlid fi shes of Peru and synonymized Acara freniferus COPE, 1872 (which was a valid taxon within the "Aequidens" dorsiger group) to L. fl avilabris, because its description was based on specimens not distinguisable from L. fl avilabris.Populations of Laetacara dorsigera from Argentina were described by CASCIOTTA (1998), and more recently OTTONI & COSTA (2009) re-described L. dorsigera based on specimens from Brazil.Laetacara dorsigera is distributed in the rio Guaporé and the lower rio Mamoré drainages of the Amazon basin and in the rio Paraguay and the middle rio Paraná of the rio Paraná basin in Argentina, Brazil and Paraguay (OTTONI & COSTA, 2009).However, Laetacara curviceps is taxonomically not well known.This species was introduced to the German aquarium trade in 1909 as "Acara thayeri".Later it was recognized as a new species and was described by AHL (1924), the former curator of Herpetology in the Berlin Museum, as Acara curviceps based on specimens obtained from the tropical aquarium-fi sh trade from "Amazonenstrom".
In this paper we present a re-description of Laetacara curviceps based both on the types and additional material from Município Parintins and Município de Óbidos, rio Amazon basin.

Materials and Methods
Material is deposited in MNRJ, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro; MTD F, Museum für Tierkunde Dresden Fish Collection, Dresden, Deutschland; UFRJ, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro and ZMB, Museum für Naturkunde, Berlin.We followed the species delimitation method proposed by DAVIS & NIXON (1992).Measurements and counts follow OTTONI & COSTA (2008), with the addition of last anal-fi n spine length, which is a measurement from the beginning to the end of the last anal-fi n spine; number of proximal radial on dorsal-fi n base; number of scales along the transversal series of the peduncle depth; number of scales between lateral lines; number of scales between the end of upper lateral line and dorsal-fi n base.Measurements are presented as percentages of standard length (SL), except for those related to head morphology, which are expressed as percentages of head length (HL).Measurements were taken on the left side of each specimen with digital calipers under a binocular microscope.Osteological studies were made on cleared and counterstained (C&S) specimens prepared according to TAYLOR & VAN DYKE (1985).Vertical bars are numbered from the caudal fi n to the snout.Spots are similarly numbered.Since the type specimens are very stiff, overgrown and not well preserved, it was not possible to obtain accurately all measurements and counts.Examined material of L. curviceps is listed under species account.Comparative material used is listed in STAECK & SCHINDLER (2007) and OTTONI & COSTA (2009).Anterior portion of the dorsal fi n rounded and the posterior region pointed.Tip of dorsal fi n reaching vertical through middle of caudal fi n.Anal fi n rounded anteriorly, pointed posteriorly.Tip of anal fi n reaching vertical through middle of caudal fi n.Caudal fi n not particularly long, subtruncate.Pectoral fi ns pointed.Pectoral-fi n base on vertical through dorsal-fi n origin.Tip of pectoral-fi n reaching vertical through vertical trunk bar 4. Pelvic fi n pointed.Pelvic-fi n base on ver-tical through third spine of dorsal fi n.Tip of pelvic fi n reaching vertical through base of fi rst spine of anal fi n.Trunk and caudal peduncle covered with ctenoid scales.Head covered with cycloid scales.

Key for the
Ceratobranchials 1-4 without tooth plates.Two supraneurals and a wide ectopterygoid.
Ceratobranchial 5 partly sutured and relatively robust, with 5-8 teeth along midline and 19-20 teeth along posterior margin.Posterior teeth usually more com pressed.Posterior and medial teeth larger than lateral and anterior teeth.Posterior teeth bicuspid, curved forward.Large laterally compressed teeth bicuspid (Fig. 3).

Colouration (in alcohol)
. Side of body light brown with seven dark brown bars between posterior limit of caudal peduncle and posterior margin of opercle.Trunk bars usually forked.Two dark spots; fi rst spot elliptical on base of caudal fi n through lower lateral line; second one on junction between longitudinal stripe and vertical trunk bar 5. Interrupted longitudinal stripe brown  Colouration (in life).For general appearance and colour pattern see Fig. 1 and 2. Live colouration variable, depending on mood.Adult specimens with bluish or turquoise ground colour.Nape and dorsal region dark grey.On snout and interorbital region alternating dark and light stripes, below the eyes red and greenish iridescent stripes.Gill covers grey with some light greenish or turquoise iridescent dots.Scales on anterior body sides with thin dark posterior margin.Body sides with a dark horizontal mid-lateral band, extending from posterior margin of orbit to upper part of caudal-fi n base.Dark bars and posterior part of horizontal band often not clearly visible.Bright light zones above and below the dark band extending to the mid-lateral spot.
Above dark lateral band a reddish stripe often disrupted into widely spaced small blotches.Dorsal fi n grey to bluish, with narrow lighter margin and a dark spot above the bar of the mid-lateral spot, in females more conspicuous than in males.Posterior soft part with light dots.Anal fi n bluish, posterior orange, with dark margin and light dots.Pectoral fi ns hyaline.Pelvic fi ns greyish, blue with greenish iridescent stripes.Caudal fi n bluish, posterior dark yellowish with conspicuous pattern of light dots and dark margin.
Type specimens.Selected measurements of the type specimens are given in Tab.1.The holotype is fi gured in AHL (1924: fi g.5).The types are aquarium specimens and are larger (slightly overgrown) than wild caught ones .The specimens have lost all colours and dark pigments.Ground colour evenly dirty yellowish to pale brownish.Dorsal-fi n spines Observations in the aquarium showed that L. curviceps is a monogamous substrate spawner.Both male and female take care of the brood.
Distribution.South America: Amazon, in lower portions of tributaries of the Amazon river drainage in Brazil.

Discussion
Laetacara curviceps is similar to both L. dorsigera and L. araguaiae in general appearance, body shape and comparative small size (usually < 50mm SL versus > 50 mm in L. thayeri, L. fl avilabris and L. fulvipinnis).From the remaining species of the genus it is distinguished by character states given in the diagnoses and in the key.The year of the description of the taxon Acara curviceps Ahl is often given as 1923 (e.g.ESCHMEYER & FRICKE, 2009;KULLANDER, 2003).However, on the cover page of the "Mitteilungen aus dem zoologischen Museum in Berlin" it is mentioned that the issue, including the original description, was distributed in February 1924.On the fi rst page of AHL's paper (AHL, 1924) there is only a remark "Eingesandt im Juni 1923" (received in June 1923).Thus, the year of the publication is 1924.
In the description, AHL (1924) mentioned eight type specimens: one type (the holotype) and 7 cotypes (paratypes).However, there are only seven specimens inventoried by PAEPKE (1995) and re-examined by us for the current study.It seems that one specimen (one paratype) is lost.
There are differences in measurements and counts between the type specimens and the fresh material.However, we consider these differences as artifi cial instead of natural ones, because the types are overgrown (they were kept in aquaria for years before fi xation) and not well preserved (possibly dead before preservation).
Laetacara curviceps, as reported by KULLANDER (1986) and OTTONI & COSTA (2008), posseses the hyoid with a deep notch on the dorsal margin of the anterior ceratohyal.A character proposed by KULLANDER (1986) as a synapomorphy of the species of the genus Laetacara (although KULLANDER (1986) examined osteological characters in L. fl avilabris and L. curviceps only).However, neither CASCIOTTA (1998) for L. dorsigera nor STAECK & SCHINDLER (2007) for L. fulvipinnis observed such a deep notch.This character was later confi rmed by OTTONI & COSTA (2009) in L. dorsigera, L. curviceps and L. araguaiae.During this study, however, there were specimens of L. curviceps osteologically analysed which possess a deep notch on the dorsal margin of the anterior ceratohyal only in one hyoid (two specimens), and others in both (two specimens) (Fig. 4).Therefore, it seems doubtful to use this character state as a diagnostic synapomorphy of the genus Laetacara.
Following SMITH et al. (2008), Laetacara is a component of the subfamily Cichlinae and the tribe Cichla somatini, closely related to Nannacara REGAN, 1905 andCleithracara KULLANDER &NIJSSEN, 1989.Discussion about relationship of the Laetacara species can not be done presently, since phylogenetics studies on Laetacara are not available yet.A study about the systematics of the genus is required.
between trunk bar 1 and margin of opercle, lighter and inconspicuous between bars.Side of head light brown with darker colouration on opercle.Dorsal fi n with one black spot above trunk bar 5 and usually a spot above trunk bar 4, in both sexes.Dorsal and anal fi ns light brown, with dots on posterior portion of fi ns.Caudal fi n light brown, with dots usually between base and middle of caudal fi n, darker near caudal peduncle.Pectoral fi n hyaline, pelvic fi n brown.
Description (based on non type specimens with SL > 26.0 mm).Morphometric data are summarized in Table1, meristic data in Table2.Dorsal profi le slightly convex from snout to caudal-peduncle origin, leaner between snout and dorsal-fi n origin.Ventral profi le slightly convex from snout to caudal-peduncle origin.Caudal peduncle approximately straight ventrally and dorsally.Body profi le elongate, laterally compressed.Lower jaw slightly shorter than upper one.Jaw teeth caniniform.Teeth hyaline to red at tip.Opercle not serrated.Urogenital papilla externally visible, rounded.