AMAZONIANA X 2 223 - 236 Kiel, Oktober 1981 Keratella rotifers found in Brazil, and â survey of Keratella rotifers from the Neotropics by Paul N. Turner Dr. Paul N. Turner, Dept. Invert. Zool., Nat. Mus. Nat. Hist. Washington, D. C. 20560, USA (accepted for publication: May 19871 Abstract Eight Brazilian lakes sampled by Francisco de Assis Esteves and Maria do Socorro R. Ibañez lrere exanined for ¡otifers. Of the 57 species found, four were members of the genus Keratella, A literature search revealed about 15 species and subspecies of Kerøtella recorded from the Neotropics, 1 1 of these frorn Brazil. All known Neotropical Keratella rotifers are discussed and figured, with highlights on the endemics. Related species are discussed when confnsion may arise with identifications. Taxonomic details of specific significance are listed in order of importance, and the state ofexpert consensus about this genus is given. Ecology and distribution of these rotifers are also discussed. Key words : Rotifers, Keratella, distribution, Neotropics, South America. Resumo Oito lagos brasileiros pesquisados por F. A. Esteves e M. S. R. Ibañez foram examinados a fim de determinar as espécies de Rotifera presentes nos mesmos. Entre as 57 espécies distintas que foram constatadas nos lagos, 4 foram membros do gênero Kerat:ella. Pesquisa na lite¡atura científica revelou registros de cerca de 15 espécies e subespócies de Keratella nas regiões neotropicais, sendo 10 espécies registradas no Brasil. Fornecem-se figuras de todas as espécies de Keratellø atualmente registradas nas regiões neo- tropicais, com ênfase ãs espécies endêmicas. Discutem.se casos de possível confusão entre espécies parecidas. Detalhes taxonômicos importantes são listados em ordem da sua importância, e um resumo fornecido do estado atual das opiniões dos especialistas sobre o taxon. Discutem-se brevemente também a ecologia e á¡eas de distribuiçâo <lestes rotíferos. 0065-6755 | 1987 | 223 I @ MPI für Limnologie, AG Tropenökologie, Plön; INPA, Manaus 223 1 lntroduction 3. Taxonomic Considerations of the genus Keratella genus and often abundant around the world. Brazl,ian waters are the most documented Neotropical waters for rotifer records Rotifers of the Keratellø are common Taxonomy within the genus is based on the number and pattern of lorica facets, relative (AHLSTROM 1 93 8 ; GILLARD 1967 ; GREEN 197 2a;HAUER 19 53, 1965 ; KOSTE 1972a, posterior), relative lengths and number of l9l2b, 1913, 1914; KOSTE & HARDY 1984; KOSTE & ROBERTSON 1983; KOSTE et proportional size of body widths (anterior and placement posterior insertions. Six anterior spines are always al. 1984; SCHADEN 1978). (For the purposes of this paper, Neotropics will denote the caudal spines, and of spine Keratella reducta HUBER-PESTALOZZI, biogeographical realm south of the Tropic of Cancer). The Amazon occupies most of the present (with one non-neotropical exception that once considered, but are probably not literature but coastal Brazilian lakes are also noted (DUSSART et al. 1984). Neotropical 1929). Two elements of morphology were nowusefultaxonomicallyare: 1)numberof facets visible onlorica,regardlessof rotifer distribution is discussed in a global context in several papers (DE RIDDER 198 1 ; pustulation granulation ventral or dorsal plates. GREEN 1972b; DUMONT 1983;DUSSART et al. 1984). Additionally, regional papers pattern, and 2) or of the pattern facets distinguishable on the lorica vary have shown distribution patterns and geographical sirnilarities between various Neotropical Iængth of spines, and number of tremendously within this genus (AHLSTROM 1943). KOSTE (1978, 1979) distinguishes species compositions (CARLIN-NILSON I 93 5 ; LEENTVAAR I 975, 1979 ; MURRAY quadratq, cochleøris. He further maintains 1913;and THOMASSON 1955, 1980). three broad Formenkreise i valga-tropica and many other species groups with morphological stability Although preliminary documentation is becoming available, Neotropical rotifers in that without additional study, unranked. the present uncertainties about taxonomic criteria for regional environments are not yet fully explored (DUSSART et al. 1984). KOSTE & DE remain Considering speciation, RUTTNER-KOLISKO (1974) suggests three groups: quadrata, serrulata and PAGGI (1982) show 15 references for Braz ilian waters, and at least four more references cochlearis. does not necessarily agree with Ruttner-Kolisko's are available since 1982. Argentina is the second most documented country for rotifers, Although this author speciation criteria and overall concept of rotifer taxonomy, her groups are used in this for which nine references are noted in KOSTE & DE PAGGI (1982), and at least one paper because of their functional and descriptive nature. Representative dorsal lorica other is available since 1982. Although Argentina and Chile are considered part of the Neo- plate group lead species noted Figures 1k, 11, tropics, their climate must be considered temperate. patterns of each are illustrated by their if and lc&drespectively. Knowledge of the systematics and ecology of Brazilian Rotifera is incomplete but The grovp, quadralø, representatives in the Neotropics are K. quadrata (mosf improving. Taxonomic studies and baseline data of regional Neotropical rotifers are also fìrst forms and itcluding K. kostei and K. tropica (including form brehmi). scarce. As more sampling takes place in the region, investigators should be encouraged to variations frenzeli), Perhaps Keratella procurva, K. lenzi and K. nhamunda are transitional into the seryulata properly identify or describe the rotifers encountered in their zooplankton samples. Some group. The serrulata group in South America, contains K. serrulqta serrulatø. The spineless available references useful to interested ¡esearchers are KosTE (1978) and RUTTNER- KOLISKO (1e74). serruløtq f. curvicornis has not been recorded in the Neotropics. Transitional animals from serrulqtq inlo cochlearis are K. nhamunda, K. americsna, K. yamana, and K. ona. The cochlearis group contains K. cochleans (and forms), K. tecta and K. thomassoni. 2. Description of Study Area This author found 57 species ofrotifers in zooplankton samples from southeastern Brazil (State Table 1 : Kerøtella species groupings for Neotropical rotifers (partially from RUTTNER- of Rio de Janeiro) collected by Dr. Francisco Esteves ín 1983, and frorn northeastern Brazil (State of KOLTSKO 1974) Maranhã'o) invcstigated by Dr. Maria S. R. Ibaiìez in 1984. The lakes that contained Keratella rotifers include: quadrata serruløta cochlearis group gfoup group Numbe¿. Name Approx. Coordinates Sample date quadrøta serrulata cochlearis 1 Lagoa de Cima (21 - 4sS 041 - 30w) 26 lan & l6 Sep 1983 quødrata 2. Lagoa Carapebús (22 - r3S 041 - 37W) 26 Jan 1983 frenzeli procurva ona 3. Lagoa Comprida (21- t7S 041- 39w) 26 Jan 1983 ftopica tecta 4. Lagoa Cabeunas (22 - l85 041 - 42W\ 14 Sep l9B3 lenzi lenzi 5. Lago Açú (03 - sos 044 - 5sw) Nôv 84 &Oct 1985 tropica brehmi thomassoni 6. Lago Viana (03 - sOs 044 - s6w) 2 Oct 1985 nhamunda amertcana kosteí yamana Lakes I - 4 are in the zoogeographical province of Tupi. Lakes 5 & 6 a¡e in the zoogeographical province of Hylaea (FITTKAU 1969). ESTEVES et al, (19g4) documents physical and chemical con_ (Species tlitions in thc Rio lakcs. peculiar to the Neotropics are inserted into RUTTNER-KOLISKO's scheme where I felt most appropriate. However, this scheme may still be inadequate to sl'row the specific relationships between Chapter4.lists all known Keratella ¡otife¡s from the Neotropics, with lake numbe¡s beside the rotifers in this region). ¡otifers found by me in Braztl. Keratella procurva is a new recorcl for Brazil. All known Keratella ¡otifers are subsequently discussed, in context ol their distribution in the region. 224 225 These 'groupings' are useful when species characteristics cannot be distinguished. Complete little in the subtropics.' He considers 12 Keratellø species as being valid for South America, parameters non- documentation of environmental, ecological and chemical of rotifers by with as many as six New World endemics. More endemics will probably be encountered as specialist researchers will ultimately contribute to the eventual definition of species which closer scrutiny is given to existing and newly discovered animals. are presently indistinguishable by morphologr alone. Table 1. shows RUTTNER-KOLISKO Of the 57 different species found by this author, only four were Keratella rotifers. (1914) species groups, and known Neotropical rotifers, with insertions of new Neotropical Other authors have recorded a total of 15 species of Keratella from the Neotropics, 10 of rotifers into her arrangement. them from Brazil (KOSTE & DE PAGGI 1982;KOSTE & ROBERTSON 1983). 4. List of Keratellø rotifers found in Neotropics 6. Keratella Species and Distribution There follows a list of all species of Kerøtellq rotifers recorded from the Neotropics. 6.1 Kerøtella amerícana CARLIN, 1943;Fie. la & b. Records of the four species from the present study are indicated by the lake numbers in SYN.: Anuraea stipitata ZELINKA, 1907, K. stipitata, HARRING 1913, parentheses. K. stipitata, EHRENBERG after COLLIN et aL (1912) and after HUDSON & GOSSE (l 889). K. gracilenta AHLSTROM, 1943, K. lenzi f . caud(ttu, KOSTE 1 972. Keratella americana CARLIN (1,4, 5,6) Keratella americana has particular dorsal lorica sculpturing with four median K er at ell a c o c hl earis coc hle ar is GOSSE (2,4,5) unpaired facets and no sub-facets, which especially characterize this animal.