TERM OF USE This pdf is provided by Magnolia Press for private/research use. Commercial sale or deposition in a public library or website site is prohibited. Zootaxa 1616: 49–59 (2007) ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ ZOOTAXA Copyright © 2007 · Magnolia Press ISSN 1175-5334 (online edition) Larval morphology in four species of Madagascan frogs of the subgenus Brygoomantis (Mantellidae: Mantidactylus) ANGELIKA KNOLL1, JÖRN KÖHLER2,6, FRANK GLAW3, MEIKE TESCHKE4 & MIGUEL VENCES5 1Technical University of Darmstadt, FB Biologie, Schnittspahnstr. 10, 64287 Darmstadt, Germany. E-mail: [email protected] 2Department of Natural History – Zoology, Hessisches Landesmuseum Darmstadt, Friedensplatz 1, 64283 Darmstadt, Germany. E-mail: [email protected] 3Zoologische Staatssammlung, Münchhausenstr. 21, 81247 München, Germany. E-mail: [email protected] 4Institute for Genetics, Evolutionary Genetics, University of Cologne, Zuelpicher Str. 47, 50674 Köln, Germany. E-mail: [email protected] 5Technical University of Braunschweig, Spielmannstr. 8, 38106 Braunschweig, Germany. E-mail: [email protected] 6Corresponding author Abstract We describe the tadpole morphology of four species of frogs classified in the endemic Madagascan subgenus Bry- goomantis of the genus Mantidactylus, based on larval specimens identified by DNA barcoding: Mantidactylus betsilea- nus and M. biporus, and two so far undescribed species that are here named M. sp. aff. betsileanus "very slow calls" and "Vohidrazana" referring to their bioacoustic features or collecting locality. The tadpoles of these four species are brown to yellowish benthic forms with a depressed body shape, dorsally directed eyes and relatively low fins. The oral discs are generalised and all species exhibit a wide gap in dorsal papillae. There is variation among different developmental stages with regard to the keratodont row formulae. In Mantidactylus betsileanus, younger stages (25 and 26) exhibit the formula 1:3+3/1+1:2, whereas it is 1:4+4/1+1:2 in older stages (36 and 38). In M. sp. aff. betsileanus "very slow calls", kerat- odont row formulae vary within one developmental stage (25–26) from 1:3+3/3 to 1:4+4/3, whereas it seems to be con- stantly 1:4+4/3 in all examined developmental stages of M. sp. aff. betsileanus "Vohidrazana". In general, the larvae of the different Brygoomantis species studied are morphologically similar to each other. Differences between species mainly concern colouration, shape of body and the number of keratodonts per millimetre, which is approximately 38 in M. betsileanus, 50 in M. biporus, and 60 in the two undescribed species. Key words: Amphibia, Mantellidae, Mantidactylus, Brygoomantis, Mantidactylus betsileanus, M. biporus, tadpole descriptions, DNA barcoding Introduction The anuran family Mantellidae comprises a large number of species endemic to Madagascar and the Como- ros. Among them is the subfamily Mantellinae which was considered to contain two genera: Mantella Bou- lenger, 1882 and Mantidactylus Boulenger, 1895 (Vences & Glaw 2001). Recently, a molecular phylogenetic analysis revealed the paraphyly of the genus Mantidactylus which consequently was partitioned into seven monophyletic genera (Glaw & Vences 2006), plus a further genus described subsequently (Glaw et al. 2006). According to this new proposal for classification, the genus Mantidactylus sensu stricto contains six clades of subgeneric rank: Brygoomantis Dubois, 1992, Hylobatrachus Laurent, 1943, Chonomantis Glaw & Vences, 1994, Maitsomantis Glaw & Vences, 2006, Ochthomantis Glaw & Vences, 1994 and Mantidactylus. Species placed in the subgenus Brygoomantis by Dubois (1992) were formerly known as the Mantidacty- Accepted by S. Carranza: 24 Aug. 2007; published: 17 Oct. 2007 49 TERM OF USE This pdf is provided by Magnolia Press for private/research use. Commercial sale or deposition in a public library or website site is prohibited. lus ulcerosus species group (e.g. Blommers-Schlösser 1979). Species of this lineage are small to medium- sized (adult snout-vent length 17–68 mm) frogs, showing riparian to semiaquatic habits along stagnant or run- ning water bodies, with diurnal and nocturnal activity (Glaw & Vences 1994, 2006). As far as known, egg deposition is terrestrial in a single clutch (e.g., Blommers-Schlösser 1979). The known larvae of Brygooman- tis represent a more or less generalised type of benthic feeders with small mouthparts exhibiting a wide dorsal gap in their marginal papillae (Blommers-Schlösser 1979). A previously underestimated problem connected with the systematics of Brygoomantis is the high diver- sity of unidentified cryptic species. Currently, the subgenus is considered to contain eleven species (Glaw & Vences 2006). However, at least some nominal species as defined by Blommers-Schlösser & Blanc (1991) display distribution patterns barely linked to the identified biogeographic regions, and differences in their advertisement calls as well as strong genetic divergence strongly suggest the presence of species complexes instead of one single taxon, although differentiation according to the morphology of adults is often highly problematic (Vences et al. 2006). A recent analysis by A. Aumüller, F. Glaw and M. Vences (in progress), based on morphological re-analyses of types, mitochondrial DNA sequences and analysis of advertisement calls indicates that the species M. ulcerosus, M. betsileanus and M. biporus as defined by Blommers-Schlösser & Blanc (1991) in fact need to be partitioned into at least 16 separate species. As a consequence, former tadpole descriptions (Arnoult & Razarihelisoa 1967; Blommers-Schlösser 1979) were possibly based on more than one species and the assignment of taxon names to described popula- tions was not reliable from the present point of view. The goal of this contribution is thus to provide detailed descriptions of the larval morphology of four species of Mantidactylus of the subgenus Brygoomantis which were unequivocally identified according to a DNA barcoding approach (see Thomas et al. 2005). This paper is part of a series of ongoing tadpole descriptions aimed at documenting the morphological diversity of Mada- gascan anuran larvae (e.g., Raharivoloniana et al. 2003; Grosjean et al. 2006; Vejarano et al. 2006; Randrian- iaina et al. 2007). Material and methods Tadpoles were collected in the field, euthanised by immersion in chlorobutanol solution, and immediately sorted into series based on their morphology. From each series at least one specimen was selected and a tissue sample from its tail musculature or fin taken and preserved in 99% ethanol. These specimens are here named “DNA vouchers”. After tissue collection, all specimens were preserved in 4% formalin. Specimens were deposited in the Zoologische Staatssammlung München, Germany (ZSM). Tadpoles were identified using a DNA barcoding approach based on a fragment of the mitochondrial 16S rRNA gene, which is known to be sufficiently variable among species of Malagasy frogs (Thomas et al. 2005). The ca. 550 bp fragment was amplified using primers 16Sa-L and 16Sb-H from Palumbi et al. (1991) applying standard protocols, resolved on automated sequencers, and compared to a near-complete database of sequences of adult Malagasy frog species. Identification was considered to be unequivocal when the tadpole sequence was 99–100% identical to an adult specimen from the same geographical region, and not more sim- ilar to any sequence from another species. DNA sequences were deposited in Genbank (accession numbers EF606875- EF606886; accession numbers of comparative adult specimens included in the sequence sets AY847959-AY848683 and AJ315909-AJ315913). As outlined in the introduction, taxonomy of Brygoomantis is currently under revision, and many new species are awaiting description as well as synonyms awaiting resurrection. Providing stable names for the taxa identified is therefore not possible in all cases. The most recent comprehensive account on Malagasy frogs is the audioguide of Vences et al. (2006). We here partially follow the names introduced in this publica- tion to refer to forms that have not yet been assigned Linnean nomenclatural names, and we explain the iden- 50 · Zootaxa 1616 © 2007 Magnolia Press KNOLL ET AL. TERM OF USE This pdf is provided by Magnolia Press for private/research use. Commercial sale or deposition in a public library or website site is prohibited. tity of each form in a small taxonomic note in the descriptive accounts. Because the DNA sequences of each tadpole series (as available from Genbank) provides an unambiguous tag, it will be possible to trace the iden- tity of these tadpoles, also if in the future the taxonomy of Brygoomantis changes. Terminology in morphological descriptions and landmarks for measurements follow Altig & McDiarmid (1999) and Grosjean (2006). Developmental stages were determined according to Gosner (1960). Keratodont row formulae follow the scheme of Dubois (1995). Body length and tail length were measured using a digital caliper (effective range: 0–150 mm; precision: 0.03 mm; repeatability: 0.1 mm). Other measurements were taken using a stereo microscope with measuring device. Drawings are mainly based on pictures taken with a digital camera with close-up lenses. Pictures of the oral apparatus were taken using a stereomicroscope with a mounted microscopy camera. All specimens of each series were examined to complete information on struc- tures missing in the DNA voucher according to the tissue sampling as well