Coevolution of the olfactory organ and its receptor repertoire in ray-finned fishes

Ray-finned fishes (Actinopterygii) perceive their environment through a range of sensory modalities, including olfaction 1,2. Anatomical diversity of the olfactory organ suggests that olfaction is differentially important among species 1,3,4. To explore this topic, we studied the evolutionary dynamics of the four main gene families (OR, TAAR, ORA/VR1 and OlfC/VR2) 5 coding for olfactory receptors in 185 species of ray-finned fishes. The large variation in the number of functional genes, between 28 in the Ocean Sunfish Mola mola and 1317 in the Reedfish Erpetoichthys calabaricus, is the result of parallel expansions and contractions of the four main gene families. Several ancient and independent simplifications of the olfactory organ are associated with massive gene losses. In contrast, polypteriforms, which have a unique and complex olfactory organ, have almost twice as many olfactory receptor genes as any other ray-finned fish. These observations suggest a functional link between morphology of the olfactory organ and richness of the olfactory receptor repertoire. Further, our results demonstrate that the genomic underpinning of olfaction in ray-finned fishes is heterogeneous and presents a dynamic pattern of evolutionary expansions, simplifications and reacquisitions.

Some Copepoda Parasitic on Fishes of the New Zealand Region

<p>Material representing 38 species of parasitic Copepoda, Order Caligoida, from New Zealand marine fishes, belonging to 20 genera and six families is discussed. Except for Lepeophtheirus erecsoni Thomson, of which only damaged material was available, the species are described and figured in detail. Previous records from New Zealand waters are discussed. The name Caligus vicarius is proposed for C. longicaudatus Brady which is preoccupied. Species examined and their hosts are as follows (new hosts for previously known species, and previously known species newly recorded from New Zealand are marked with asterisks) - Caligidae: Caligus brevis Shiinox on Pseudolabrus pittensisx, P. milesx and P. celidotusx; C. aesopus Wilsonx on Seriola grandisx; C. pelamydis Kroyerx on Thyrsites atunx; C. buechlerae Hewitt on Tripterygion sp.; Lepeophtheirus erecsoni Thomson on Latridopsis ciliaris; L. scutiger Shiinox on Pseudolabrus pittensisx, P. milesx and P. celidotusx; L. insignis Wilsonx on Mola mola; L. polyprioni Hewitt on Polyprion oxygenios and P. moeone; L. argentus Hewitt on Hyperoglyphe porosa; L. heegaardi Hewitt on Lepidopus caudatus; L. distinctus Hewitt on Genypterus blacodes; Euyphoridae: Gloiopotes huttoni (Thomson) on Makaira mitsukurii and M. marlina; Elytrophora brachyptera Gerstaekerx on Thunnus alalunga and. T. maccoyix; Pandaridae: Nesippus orientalis Hellerx on Mustelus antarcticus and Notorhynchus pectorosusx; N. borealis (Steenstrup and Lutken)x on Isurus oxyrinchusx; Dinemoura latifolia Steenstrup and Lutken on Carcharodon carcharias, Isurus oxyrinchus and Galeorhinus australis; D. producta (Muller) on Cetorhinus maximus and Carcharodon carcharias; Demoleus latus Shiinox on Squalus acanthiasx; Echthrogaleus braccatus (Dana) on an unrecorded host; E. coleoptratus (Guerin)x on Prionace glauca and Lamna nasus; E. denticulatus Smith on an unrecorded host; Phyllothyreus cornutus (Milne-Edwards)x on Isurus oxyrinchus; Pandarus bicolor Leachx on Squalus acanthias, Galeorhinus australisx, Notorhynchus pectorosusx and Cyprimulus sp.x; P. cranchii Leach on Galeorhinus australisx and Isurus oxyrinchus; Perissopus dentatus Steenstrup and Lutkenx on a hammerhead shark; Cecropidae: Cecrops latreillii Leach on Mola mola; Eudactylinidae: Nemesis lamna Rissox on Carcharodon carcharias, Cetorhinus maximus and Isurus oxyrinchus; N. robusta (van Beneden)x on Alopias vulpinus; Congericola pallidus van Benedenx on Conger vereauxix Dichelesthiidae; Pseudocycnus appendiculatus Hellerx on Thunnus alalunga; a new species of Hatschekia on Allomycterus jaculiferus; a further new species of Hatschekia on Lepidopus caudatus; Anthosomidae: a new species of Pseudolernanthropus on Thyrsites atun and Jordanidia solandri; a new species of Lernanthropus on Seriolella brama; Aethon percis (Thomson) on Parapercis coelias; two new species of Aethon on Cheilodactylus macropterus and Latridopus caudatues; Anthosoma crassum (Abildgaard) on Carcharodon carcharias, Isurus oxyrinchus, Lamna nasus and Galeorhinus galeusx; this collection includes all species belonging to these families which have previously and reliably been recorded from New Zealand waters, and of which adequate descriptions exist. The similarities of the cephalic appendages of caligoid copepods to those of free living copepods is discussed. The biogeographical relationships of the species here recorded are considered and it is concluded that many of these species, particularly those parasitic on elasmobranchs, are widespread, and that many of those with apparently restricted distributions may become known from other regions, especially when the little investigated parasite faunas of fishes from the South Pacific and South Atlantic become more fully known; the hosts from which the present species have been recorded are compared; it is shown that species occurring on elasmobranchs are confined to this but show little host specificity within it; teleost parasites may be restricted to one host species, one host genus, one host family, or to host families with systematic or ecological affinities; Cecrops latreillii is unique among these parasites in occurring on three quite different and apparently unrelated host species.</p>

Some Copepoda Parasitic on Fishes of the New Zealand Region

<p>Material representing 38 species of parasitic Copepoda, Order Caligoida, from New Zealand marine fishes, belonging to 20 genera and six families is discussed. Except for Lepeophtheirus erecsoni Thomson, of which only damaged material was available, the species are described and figured in detail. Previous records from New Zealand waters are discussed. The name Caligus vicarius is proposed for C. longicaudatus Brady which is preoccupied. Species examined and their hosts are as follows (new hosts for previously known species, and previously known species newly recorded from New Zealand are marked with asterisks) - Caligidae: Caligus brevis Shiinox on Pseudolabrus pittensisx, P. milesx and P. celidotusx; C. aesopus Wilsonx on Seriola grandisx; C. pelamydis Kroyerx on Thyrsites atunx; C. buechlerae Hewitt on Tripterygion sp.; Lepeophtheirus erecsoni Thomson on Latridopsis ciliaris; L. scutiger Shiinox on Pseudolabrus pittensisx, P. milesx and P. celidotusx; L. insignis Wilsonx on Mola mola; L. polyprioni Hewitt on Polyprion oxygenios and P. moeone; L. argentus Hewitt on Hyperoglyphe porosa; L. heegaardi Hewitt on Lepidopus caudatus; L. distinctus Hewitt on Genypterus blacodes; Euyphoridae: Gloiopotes huttoni (Thomson) on Makaira mitsukurii and M. marlina; Elytrophora brachyptera Gerstaekerx on Thunnus alalunga and. T. maccoyix; Pandaridae: Nesippus orientalis Hellerx on Mustelus antarcticus and Notorhynchus pectorosusx; N. borealis (Steenstrup and Lutken)x on Isurus oxyrinchusx; Dinemoura latifolia Steenstrup and Lutken on Carcharodon carcharias, Isurus oxyrinchus and Galeorhinus australis; D. producta (Muller) on Cetorhinus maximus and Carcharodon carcharias; Demoleus latus Shiinox on Squalus acanthiasx; Echthrogaleus braccatus (Dana) on an unrecorded host; E. coleoptratus (Guerin)x on Prionace glauca and Lamna nasus; E. denticulatus Smith on an unrecorded host; Phyllothyreus cornutus (Milne-Edwards)x on Isurus oxyrinchus; Pandarus bicolor Leachx on Squalus acanthias, Galeorhinus australisx, Notorhynchus pectorosusx and Cyprimulus sp.x; P. cranchii Leach on Galeorhinus australisx and Isurus oxyrinchus; Perissopus dentatus Steenstrup and Lutkenx on a hammerhead shark; Cecropidae: Cecrops latreillii Leach on Mola mola; Eudactylinidae: Nemesis lamna Rissox on Carcharodon carcharias, Cetorhinus maximus and Isurus oxyrinchus; N. robusta (van Beneden)x on Alopias vulpinus; Congericola pallidus van Benedenx on Conger vereauxix Dichelesthiidae; Pseudocycnus appendiculatus Hellerx on Thunnus alalunga; a new species of Hatschekia on Allomycterus jaculiferus; a further new species of Hatschekia on Lepidopus caudatus; Anthosomidae: a new species of Pseudolernanthropus on Thyrsites atun and Jordanidia solandri; a new species of Lernanthropus on Seriolella brama; Aethon percis (Thomson) on Parapercis coelias; two new species of Aethon on Cheilodactylus macropterus and Latridopus caudatues; Anthosoma crassum (Abildgaard) on Carcharodon carcharias, Isurus oxyrinchus, Lamna nasus and Galeorhinus galeusx; this collection includes all species belonging to these families which have previously and reliably been recorded from New Zealand waters, and of which adequate descriptions exist. The similarities of the cephalic appendages of caligoid copepods to those of free living copepods is discussed. The biogeographical relationships of the species here recorded are considered and it is concluded that many of these species, particularly those parasitic on elasmobranchs, are widespread, and that many of those with apparently restricted distributions may become known from other regions, especially when the little investigated parasite faunas of fishes from the South Pacific and South Atlantic become more fully known; the hosts from which the present species have been recorded are compared; it is shown that species occurring on elasmobranchs are confined to this but show little host specificity within it; teleost parasites may be restricted to one host species, one host genus, one host family, or to host families with systematic or ecological affinities; Cecrops latreillii is unique among these parasites in occurring on three quite different and apparently unrelated host species.</p>

Predicting seasonal occurrence of leatherback turtles (Dermochelys coriacea) in eastern Canadian waters from turtle and ocean sunfish (Mola mola) sighting data and habitat characteristics

Part of the western Atlantic population of leatherback turtles (Dermochelys coriacea (Vandelli, 1761)) forage in Canadian waters, where high-use areas have been identified using satellite telemetry and opportunistic sightings. Here, we use sightings of leatherback turtles and ocean sunfish (Mola mola (Linnaeus, 1758)) obtained during a systematic large-scale aerial survey, along with opportunistic turtle sightings, to examine the seasonal occurrence and distribution of leatherback turtles in eastern Canada. Using environmental correlates, we predict the spatial and seasonal development of potentially suitable habitats. All data sets confirmed the presence of leatherback turtles off Nova Scotia during summer. They also highlighted turtle occurrence off southern Newfoundland. Opportunistic sightings suggest a seasonal shift in main turtle concentrations from southwest to northeast, with use of southern Newfoundland waters extending into September. A generalized additive model linking environmental characteristics and turtle observations suggests adding the Grand Banks off Newfoundland and waters east of Anticosti Island in the Gulf of St. Lawrence to the potentially important habitat for leatherback turtles. Direct observations helped delineate habitat currently used by leatherback turtles. In the context of climate change, this modelling approach may improve our ability to forecast changes in turtle habitat suitability and the risks of entrapment or collision associated with potentially changing usage patterns.