摘要:

Coupling and oviposition behaviour were studied in two macrodiplacinid libellulids–Aethriamantha rezia(Kirby) andUrothemis assignataSelys in die Ibadan area of Nigeria. Sperm translocation occurs in both libellulids after the male has secured the female. Pre‐mating tandem flight occurs prior to mating. Mating is long inA. rezia(384–716 s, mean 480) and shorter inU. assignata(69–122 s, mean 94). After mating, both libellulids rest in tandem, the duration being longer inA. rezia(25–82 s, mean 42) than inU. assignata(0–24 s, mean 11). This is followed by tandem exploration inA. reziaand later by oviposition, the male guarding the female. InU. assignata, tandem exploration is absent, but oviposition is usually in tandem. The duration of oviposition is similar in both libellulids–6 7–148 s, mean 95, inA. reziaand 63–183 m, mean 133, inU. assignata. Aethriamantha reziaoviposits mainly onPistia stratioteswhile plants utilized byU. assignataare more variable, althoughP. stratiotesis also preferred. The number of eggs laid per oviposition is high, averaging 435 inA. reziaand 398 inU. assignata.High population of males at water prolongs mating and oviposition in the two species. The ecological habitat

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1981.tb01574.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The history of ostariophysan classification is summarized and it is noted that traditional concepts of relationships have never been supported by characters found to be unique to the taxa. We present a new hypothesis of relationships among four of the five major ostariophysan lineages: Cypriniformes, Characiformes, Siluroidei, and Gymnotoidei (Otophysi). Cypriniforms are the sister‐group of the remaining three (Characiphysi), and characiforms are the sister‐group of siluroids plus gymnotoids (Siluriformes). Placement of the Gonorynchiformes as the sister‐group of the Otophysi is supported by additional evidence. Each of the five lineages is monophyletic. Analysis was concentrated upon species thought to be the least specialized within each lineage; choices of these species are discussed.Chanos is determined to be a relatively primitive gonorynchiform morphologically and the sister‐group of all other Recent members of the order.OpsariichthysandZaccoare found to be morphologically primitive cypriniforms. We propose that a monophyletic group comprising the Citharinidae and Distichodontidae forms the sister‐group of all other characiforms. Within the two families,Xenocharaxis the least specialized. We suggest thatHepsetus, the erythrinids, and the ctenoluciids are more derived than the distichodontids and citharinids, and may form a monophyletic group within die characiforms. The traditional hypothesis thatDiplomystesis the primitive sister‐group of all Recent siluroids is substantiated. Our evidence suggests thatSternopygusis the most primitive gymnotoid morphologically; but rather than being the sister‐group of all other gymnotoids, it is the primitive sister‐group within a lineage called the Sternopygidae by Mago‐Leccia.Previous explanations of otophysan distribution have been based on notions of relationships which are unsupported by the evidence presented herein. Our own analysis of relationships serves primarily to make clear the extent of sympatry, and therefore the probability of dispersal, among the major ostariophysan lineages. The extent of sympatry, together with the widespread distribution of ostariophysans, suggests that the group is older than previously supposed, and our hypotheses of relationships among the characiforms implies that many of the extent characiform lineages evolved before the separation of Africa and South America. Further understanding of ostariophysan distribution must await phylogenetic analysis within each of the five major lineages so that distributions linked with vicariance patterns and dispersal events

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1981.tb01575.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The isolated population of grass snakes,Natrix natrix(L.), on the island of Gotland in die Baltic Sea is described and illustrated. Comparisons are made with the surrounding mainland grass snake. On the basis of morphological and ecological divergence, the conclusion is drawn that the Gotland population represents a new subspecies.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1981.tb01576.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1981.tb01577.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1981.tb01578.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY