Lecture 20- Biogeography

Primary freshwater fishes:

• e.g., lungfishes, paddlefishes, bichirs, extant osteoglossids, minnows, catfishes (except Ariidae), characins, pikes, centrarchids

Secondary freshwater fishes:

• e.g., gars, killifishes, livebearers, cichlids

Diadromous fishes:

• e.g., lampreys, sturgeon, anguillid eels, salmonids

Euryhaline fishes:

• e.g., pupfishes, mollies, striped bass

Saltwater tolerant fish

body size, and whether larvae are planktonic

marine fish dispersability determined by:

Endemism

restriction and uniqueness of certain organisms to a particular place

Fish endemic to Canada

Copper redhorse, Atlantic Whitefish, and Lake Lamprey

Cosmopolitan

Widespread throughout most of the world

• Atlantic bluefin, Swordfish

Osteoglossiformes

Split apart before Pangaea split, why we see representatives in all continents as it was still connected when these primary FW fish taxa evolved

did not really occur until after breakup of Pangaea (ca. 180 mya), into Laurasia and Gondwana

• Therefore, more regional differences among most recent teleost groups

Teleost evolution

– Freshwater teleosts that arose here after 180 mya, restricted here (e.g., Esocidae, Percidae, Catostomidae)

– ca. 65 mya, NA and Eurasia separated

– Families or species that arose after that, restricted to one continent or another, if primarily freshwater

• Connections still changed intermittently (e.g., Bering Strait b/w western NA and Eurasia, Isthmus of Panama)

Laurasia (future North America and Eurasia)

• ca. 90 mya, SA, Africa, Antarctic-Australia-New Guinea,

and India-Madagascar distinct landmasses

• By 50–60 mya, India had separated from Madagascar

and both were large islands; Australia had separated

from Antarctica, and New Zealand from Australia

Gondwana (future South America, Africa, Antarctica, India, Australia)

45-55 mya

India collides with Asia in this time

35 mya

Arabia collides with Aurasia in this time

15 mya

continents near present position in this time

Holarctic (Nearctic + Palearctic)

Complete polar, boreal, and temperate northern hemisphere

Freshwater families restricted to Holarctic:

– Polyondontidae (disjunct)

– Catostomidae

– Esocidae (circumpolar – e.g., northern pike; disjunct – e.g., mudminnows)

– Percidae

Diadromous families in Holarctic:

– Petromyzontidae

– Acipenseridae

– Salmonidae

– Osmeridae

Exclusively Nearctic

• Centrarchidae and Ictaluridae

• Percopsiformes (Percopsidae, Aphredoderidae, Amblyopsidae)

• Fundulidae and Cyprinodontidae (euryhaline)

• Relict groups of archaic fishes (e.g., bowfin, gars, hiodontids – although fossil bowfins in Europe, Asia, SA; fossil hiodontids in northeastern Asia)

Palearctic (which includes temperate Asia) also with some endemic groups:

– e.g., two endemic cottoid families in ancient Lake Baikal

• And shares number of FW families with tropical Africa and Asia

– e.g., families (e.g., Cobitidae, Anabantidae, Channidae, Mastacembelidae, Clariidae) perhaps derived from fish carried on the Indian landmass from Africa to Asia and then into temperate Asia and, in some cases (e.g., loaches) in Europe

– Siluridae and Balitoridae also shared by Oriental and Palearctic regions

Middle America

• Central American and southern Mexico

• Interesting mix of North (e.g., centrarchids, cyprinids, ictalurids) and South (cichlids, characids, pimelodids) American faunas with local endemism (Goodeidae, Profundulidae, Poeciliidae, Anablepidae)

• Isthmus and Caribbean islands changing combination of islands and tectonism during most of Cenozoic

• ca. 11–4 mya, permanent land connection established, allowing “Great American Interchange”) but earlier islands had isolated fishes and resulted in widespread endemism

Neotropical

 SA isolated for some time prior to reconnection to Middle America

• Separated from Africa ca. 112–150 mya

• Richest in Characiformes (with several endemic families) and Siluriformes (likewise); also many cichlid and gymnotiform spp.

– Characiformes and Cichlidae shared with Africa, but fauna of each continent appear to be monophyletic

• Other Neotropical families closely related to marine groups and probably evolved in inland shallow seas and large lakes of the region

– e.g., Pomatotrygonidae, Clupeidae, Engraulidae, Belonidae, Sciaenidae, Soleidae

• Species rich (ca. 8000 spp. of FW fishes

Oriental

• Land connections to Palearctic and Ethiopian regions

– Although Himalayas form boundary to the north, dry areas of the Middle East form boundary to the west

• Rich in ostariophysan fishes, esp. cypriniforms and siluriforms

• Several endemic catfish families

• Other shared families include Synbranchidae, Mastacembelidae, Channidae

Ethiopian

• Africa (except Atlas mountains), Madagascar, and southern 2/3 of Arabia

• Almost entirely surrounded by ocean

• Endemic families include archaic families of primitive bony fishes:

– Protopteridae and Polypteridae

– Pantodontidae

– Gymnarchidae and Mormyridae

• Other endemic families include Malapteruridae and Mochokidae (Siluriformes)

Australian

• Only ca. 200 FW spp.

• Most in families that are largely marine or estuarine (e.g., gobies, atherinids, catfishes)

• Or diadromous (e.g., lamprey families Geotriidae, Mordacidae) and galaxiids

• Plus three archaic FW fish spp.

– Australian lungfish

– Two osteoglossids (Scleropages spp.)

• Major groups of continental FW fishes lacking (minnows, loaches, catfishes, anabantoids, channids)