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PHENOTYPIC AND GENOTYPIC VARIATION IN THE TWO KNOWN POPULATIONS OF CHIROCEPHALUS RUFFOI COTTARELLI & MURA, 1984 (ANOSTRACA), ENDEMIC TO ITALY

2001; Brill; Volume: 74; Issue: 4 Linguagem: Inglês

10.1163/156854001300104462

1568-5403

Ketmaier, De Matthaeis, Mura, Zarattini,

Fish Ecology and Management Studies

[Thus far, the endemic fairy shrimp Chirocephalus ruffoi Cottarelli & Mura, 1984 is represented in Italy by two populations only, occurring in Pollino National Park (Calabro-Lucano Apennines) and Monte Rondinaio (Tosco-Emiliano Apennines), respectively. Given the distance between the two sites (one in southern Italy, the other in northern Italy, approximately 800 km apart), the probable lack of gene flow suggested both morphological and electrophoretic studies to clarify their systematic position. SEM morphological investigations revealed clear, though slight, inter-population differences in cyst morphology. However, the substantial individual variation in male secondary sexual characters observed in both populations does not correspond to clear differences in the remaining characters of adult males. Yet, the extent of genetic divergence between the two populations evaluated by means of allozyme variation analysis at 22 loci (D = 0.259), suggests the absence of gene flow between these. Thus, as in other previous cases, morphological criteria and allozyme analysis would indicate contrasting conclusions concerning the systematic position of the taxa considered. Given the limited degree of current knowledge on the distribution of C. ruffoi in Italy, more extensive field investigations as well as the use of molecular analysis at the DNA level are needed to clarify the situation. Jusqu'a present, l'anostrace endemique Chirocephalus ruffoi Cottarelli & Mura, 1984, est represente en Italie par seulement deux populations, presentes respectivement dans le Parc national Pollino (Apennins Calabro-Lucano) et le mont Rondinaio (Apennins Tosco-Emiliano). Etant donnee la distance entre les deux sites (800 km entre l'une dans le sud de l'Italie et l'autre dans le nord), l'absence suspectee de flux genique a suggere de mener des recherches a la fois sur la morphologie et la genetique afin de clarifier le statut systematique des deux populations. Les observations realisees en microscopie electronique a balayage (SEM) ont revele des differences inter-populations, claires bien que peu marquees, dans la morphologie des œufs de duree. Cependant, la variation individuelle substantielle des caracteres sexuels secondaires chez les mâles, observee dans les deux populations, ne correspond pas aux differences clairement observees dans les autres caracteres des adultes mâles. Par ailleurs, la distance genetique, evaluee au moyen de l'analyse des allozymes sur 22 loci (D = 0,259) suggere l'absence de flux genique entre les deux populations. Ainsi, comme dans d'autres cas etudies precedemment, les criteres morphologiques et l'analyse des allozymes conduisent a des conclusions contrastees quant au status systematique des taxa consideres. En raison de la connaissance limitee de la distribution de C. ruffoi en Italie, des recherches plus extensives sur le terrain ainsi que l'utilisation de l'analyse moleculaire (ADN) sont necessaires pour clarifier la situation., Thus far, the endemic fairy shrimp Chirocephalus ruffoi Cottarelli & Mura, 1984 is represented in Italy by two populations only, occurring in Pollino National Park (Calabro-Lucano Apennines) and Monte Rondinaio (Tosco-Emiliano Apennines), respectively. Given the distance between the two sites (one in southern Italy, the other in northern Italy, approximately 800 km apart), the probable lack of gene flow suggested both morphological and electrophoretic studies to clarify their systematic position. SEM morphological investigations revealed clear, though slight, inter-population differences in cyst morphology. However, the substantial individual variation in male secondary sexual characters observed in both populations does not correspond to clear differences in the remaining characters of adult males. Yet, the extent of genetic divergence between the two populations evaluated by means of allozyme variation analysis at 22 loci (D = 0.259), suggests the absence of gene flow between these. Thus, as in other previous cases, morphological criteria and allozyme analysis would indicate contrasting conclusions concerning the systematic position of the taxa considered. Given the limited degree of current knowledge on the distribution of C. ruffoi in Italy, more extensive field investigations as well as the use of molecular analysis at the DNA level are needed to clarify the situation. Jusqu'a present, l'anostrace endemique Chirocephalus ruffoi Cottarelli & Mura, 1984, est represente en Italie par seulement deux populations, presentes respectivement dans le Parc national Pollino (Apennins Calabro-Lucano) et le mont Rondinaio (Apennins Tosco-Emiliano). Etant donnee la distance entre les deux sites (800 km entre l'une dans le sud de l'Italie et l'autre dans le nord), l'absence suspectee de flux genique a suggere de mener des recherches a la fois sur la morphologie et la genetique afin de clarifier le statut systematique des deux populations. Les observations realisees en microscopie electronique a balayage (SEM) ont revele des differences inter-populations, claires bien que peu marquees, dans la morphologie des œufs de duree. Cependant, la variation individuelle substantielle des caracteres sexuels secondaires chez les mâles, observee dans les deux populations, ne correspond pas aux differences clairement observees dans les autres caracteres des adultes mâles. Par ailleurs, la distance genetique, evaluee au moyen de l'analyse des allozymes sur 22 loci (D = 0,259) suggere l'absence de flux genique entre les deux populations. Ainsi, comme dans d'autres cas etudies precedemment, les criteres morphologiques et l'analyse des allozymes conduisent a des conclusions contrastees quant au status systematique des taxa consideres. En raison de la connaissance limitee de la distribution de C. ruffoi en Italie, des recherches plus extensives sur le terrain ainsi que l'utilisation de l'analyse moleculaire (ADN) sont necessaires pour clarifier la situation.]