Gammarus Orinos N. Sp. from the Massif Central (France): Its Genetic
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Bijdragen tot de Dierkunde, 54 (1): 139-146 — 1984 Gammarus orinos n. sp. from the Massif Central (France): its genetic and morphological distinction from Gammarus ibericus Margalef, 1951 (Crustacea, Amphipoda) by Sjouk Pinkster Institute of Taxonomie Zoology, University of Amsterdam, P.O. Box 20125, 1000 HC Amsterdam, The Netherlands & Adolf Scholl Institute of Zoology, University of Berne, Baltzerstr. 3, CH-3012, Berne, Switzerland Summary d’Espagne sont nettement différentes du point de vue biochimique, ces différences étant beaucoup plus impor- Until 1974 Gammarus ibericus known from the was only celles tantes que séparant n’importe quelles autres espèces in In that recorded type-locality Spain. year, Goedmakers (ou populations) d’Europe occidentale. On est donc arrivé the from localities in the Massif species many Central, à la conclusion les du Massif Central que populations ap- these show France. Indeed, populations a mor- great à G. orinos partiennent une espèce distincte, n. sp. L’exa- phological resemblance to the Spanish ones. These French mination minutieuse de centaines d’exemplaires in with populations were used cross-breeding experiments de France montré des différences d’Espagneet a que mor- other populations from southern France, without result. phologiques mineures mais constantes existent entre les Attempts to hybridize these populations with the G. ibericus deux espèces. from the also failed type-locality to produce any offspring. Electrophoretic studies showed that the French and different from biochemical Spanish populations are very a INTRODUCTION point of view; these differences are much greater than be- of the known freshwater tween any species (or populations) 1. In 1951 described Gammarus ibericus from western Europe. It is therefore decided that the Margalef populations from the Massif Central belong to a separate from the Fuentes de la Laguna "El Tobar" in hundreds species: G. orinos n. Careful examination of sp. the Serrania de Cuenca, central Spain. In spite of specimens from both Spain and France showed that of intensive search throughout the Iberian minor but constant morphological differences exist be- peninsula (e.g. Pinkster, 1971, the tween the two species. 1973) found outside species was never a very restricted area near the type-locality. Goed- Résumé makers (1974) who systematically sampled the Jusqu’en 1974 Gammarus ibericus était uniquement connu entire Massif Central in the middle of France, de la C’est 1974 Goed- localité-type d’Espagne. en que came upon populations that resembled G. makers mentionna l’espèce de nombreuses localités du ibericus in almost character every morphological Massif Central (France), en se fondant sur des populations and she decided that were ressemblance mor- they conspecific. qui montrent réellement une forte Pinkster studied phologique avec celles d’Espagne. Les populations du (1983) many morphological- Massif Central été utilisées des de ont pour expériences ly different populations from southern France croisement des de France avec populations méridionale, and in hybridization experiments tested the mais sans résultat positif. De même, des essais d’hybrida- significance of the morphological differences tion de populations de G. ibericus de la localité-type n’ont observed. Since of donné de Des recherches some the populations used pas progéniture. électrophoréti- montré les de France showed close ques ont que populations et (population C) a resemblance to Downloaded from Brill.com10/04/2021 06:25:40PM via free access 140 S. PINKSTER & A. SCHOLL - GAMMARUS ORINOS N. SP. the so-called ibericus from the Massif Central, a period of adaptation all experiments were run in In of population of these was also used the ex- at 15°C. February 1983 a series ex- could be started with periments. However, no offspring ever periments was freshly collected obtained from these experiments. Other animals from the Laguna "El Tobar", prov. from populations from southern France proved to be Cuenca, Spain, and with a population a G. small interfertile and were described as stupendus brook near Ste. Marguerite, dépt. by Pinkster, 1983. In the light of the previous Ardèche, France. experiments, the question arose ifthese popula- — be Results. The results can easily sum- tions from the Massif Central are conspecific marized as follows: cross-breeding was at- with G. ibericus indeed. A new series of tempted between more than a hundred mature started with G. hybridization experiments was of both the males populations and same number ibericus from the type-locality and a population of females from the other populations. In six from central France. months found hardly any precopulations were and oviposition took place in less than 10% of 2. demon- Bulnheim & Scholl (1980, 1981) the females. Offspring were never observed. criteria strated that electrophoretic can be ad- from both The homogeneous crosses popula- ditionally used as diagnostic aids in the tax- tions did well in the very experiments, easily The criteria related onomy of gammarids. are formed and had precopulations a high percent- relative mobilities of the to electrophoretic pro- of age success (60%). tein products from selected loci and the distribution of allele frequencies at polymorphic 2. Electrophoretic studies loci. The authors discussed each other's — present Methods. The methods of electrophoretic methods and of agreed to start a preliminary pro- separation enzymes and specific staining taxonomie in those of Bulnheim Scholl gram to investigate problems techniques are & freshwater the different The gammarids by applying (1981). following enzymes were assayed: methods described (electrophoresis, hybridiza- arginine phosphokinase (APK), glutamate ox- tion to the alacetate experiments, morphological studies) (two genetically independent enzymes same populations. So, all populations used by GOT-1 and GOT-2), hexokinase (HK), leucine Pinkster (1983) in his hybridization ex- aminopeptidase (LAP), mannose-6-phosphate been periments have electrophoretically ana- isomerase (MPI), and phosphoglucose with series of isomerase In lyzed, together a new populations, (PGI). addition, indophenol ox- G. ibericus from idase including Spain and central (IPO) was scored (an achromatic region France. New series of which hybridization ex- appeared upon prolonged staining on periments were run simultaneously. HK- and MPI-zymograms). the still individuals Although experiments are going on, Fourteen from each of the two and obtained the results so far do not yet allow a populations (El Tobar and Ste. Marguerite) discussion of all in- more comprehensive taxa were analyzed. the vestigated, they definitely shed new light on position of G. ibericus from Spain and the Results.— The two populations differed elec- from the Massif Central. in of populations trophoretically seven out eight enzymes analyzed. Electrophoretic identity was only observed for leucine aminopeptidase. Fig. 1 EXPERIMENTAL PART shows of of the a representative zymogram one electrophoretically different enzymes, phospho- 1. Hybridization experiments glucose isomerase. — To evaluate the of Methods. The methods used were identical significance these observa- Pinkster after tions with the of the to those described by (1983); a respect to systematics gam- Downloaded from Brill.com10/04/2021 06:25:40PM via free access BIJDRAGEN TOT DE DIERKUNDE, 54 (1) - 1984 141 marids concerned, reference must be made to phologically highly resembles G. ibericus while Careful previous investigations of Bulnheim & Scholl being genetically well differentiated. of this (1981), using essentially the same methods and morphological examination species in of is called Gammarus because of its enzyme samples comparison ten European (which orinos, gammarid species from marine, brackish and distribution pattern in the old mountainous freshwater habitats. The subspecies G. duebeni Massif Central) and G. ibericus reveals some duebeni and G. duebeni celticus could not be small but constant differences (see the sequel). distinguished electrophoretically. Genetic dif- ferentiation of the sibling species G. zaddachi and G. salinus was observed on the basis of allele DESCRIPTIVE PART loci. frequencies at polymorphic enzyme Gammarus orinos n. sp. Thus, the electrophoretic studies reported here indicate a very high degree of genetic dif- Material examined.— Thirty-five samples, all from the Massif France A ferentiation of the two populations compared, Central, (for details see appendix). distribution is published by Pinkster, 1983, fig. 6 (as which is far beyond the level expected in map G. Locus ibericus, non Margalef). typicus: France, dépt. of allopatric populations a single species. Ardèche, small brook 6 km E. of Chirols (near Vals-les- in Bains), 17-VII-1981; many specimens, many precopulation. The male holotype and 60 paratypes have been deposited in the collections of the Zoölogisch Museum, Amsterdam, coll. no. ZMA Amph. 107.744 a-b; 10 paratypes have been deposited in the Naturhistorisches Museum Bern (NMBE), Switzerland. Diagnosis.— Small to medium-sized species with slender a smooth, body. Moderately setose second antenna. Pereiopods 5 to 7 always armed with long setae in between the spines. The dorsal surface of the urosome is flat. Description. — Male: maximum length observed The 14 mm. urosome segments have no dorsal excavations or elevations. The dorsal armature consists of a mid-dorsal group of 1. of isomerase. Slots 1 Fig. Zymogram phosphoglucose to and lateral spines setae and a group on each