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Home , Acipenseriformes, Actinopterygii, Alligator gar, Bichir, Bonefishes, Bowfin

OEB 130: OF Lecture 4: Overview of ray-finned diversity () Announcements 1

1. Please review the syllabus for reading and lab information! 2. Please do the readings: for this week posted now. 3. Lab sections: 4. i) Dylan Wainwright, Thursday 2 - 4/5 pm ii) Kelsey Lucas, Friday 2 - 4/5 pm iii) Labs are in the Northwest Building basement (room B141) Please be on time at 2pm! 4. Lab sections done: first lab this week tomorrow! 5. First lab reading: Agassiz fish story; lab will be a bit shorter 6. Office hours to come Announcements 2

8 pages of general information on fish external and characters to help you learn some basic external and terminology – the last slides in the uploaded lecture Powerpoint file for today.

Please look at these before lab this week, but no need to bring them in with you.

Scanned from: Hastings, P. A., Walker, H. J. and Galland, G. R. (2014). Fishes: A guide to their diversity: Univ. of California Press.

Next Monday: prepare to draw/diagram in lecture (colored pencils/pens will be useful) Lecture outline

Lecture outline:

1. Brief review of the phylogeny and key traits so far

2. Actinopterygian : overview and introduction to key groups and selected key traits

3. Special focus on: 1. ray structure and 2. and swimblader evolution 3. Early diversity of fishes Selected key shared derived characters (synapomorphies) Review from last lecture

Chondrichthyes ( and rays and ratfishes): 1. Dentition: multiple rows of unattached teeth 2. Placoid scales: -like structure 3. Prismatic (tile-like) of 4. Fin structure: unsegmented fin rays termed ceratotrichia – bundles of fibers 5. – electric fields 6. Pelvic claspers in males

Selected key shared derived characters (synapomorphies)

Osteichthyes (―bony fish‖ including all ): Three in the Lung or air-filled from ventral part of pharynx bony covers the on each side : ―lobe fin‖ with single element (monobasic) intracranial joint (lost in many tetrapods) specialized type Actinopterygii: Single (some exceptions) Fin-rays termed ―lepidotrichia‖ – bilaminar design Specialized scale type (has pegs in early ) Ray-finned fish (Actinopterygii) phylogeny: broad overview Actinopterygii

Holostei 1 and relatives

Teleostei

†

1. Single dorsal fin 2. Fin ray structure: lepidotrichia 3. Scale structure Actinopterygii = ray-fin Actinopterygian synapomorphy #2: fin ray structure called a lepidotrich median and paired Dorsal fin A ray-finned Caudal fin fish

Pectoral fins

Anal fin

Pelvic fins Actinopterygian synapomorphy #2: fin ray structure called a lepidotrich

Ray-finned fishes have fins with unique fin rays: bilaminar, branching (usually) rays that support the fin membrane Actinopterygian synapomorphy #2: fin ray structure called a lepidotrich

Ray-finned fishes have fins with unique fin rays: bilaminar, branching (usually) rays that support the fin membrane fin ray segments

unsegmented basally

Fin membrane Fin ray mechanics

fin ray

Half ray Half ray

4 muscles control each fin ray (+3)

14 fin rays in the pectoral fin; 59 muscle bundles total per fin

    Simple ray models Fin ray mechanics (zip-loc bag movie)

A simple model fin ray Pectoral fin rays bend into flow during maneuvering

Flow

Fin curved into flow

14 Recall chondrichthyian synapomorphy #4: ceratotrich fin ray structure

Ceratotrichia: unsegmented bundles of collagenous fibers Recall chondrichthyian synapomorphy #4: ceratotrich fin ray structure

Ceratotrichia Cartilage fin supports (radials)

Shark fin Another key feature of actinopterygian evolution: and swimbladders Where do lungs come from, and what are key features of their evolution? Lungs are formed by ventral outpocketings from the which form air-filled cavities. The swimbladder is derived in evolution from ancestral lungs, and serves an important function in fishes. It can also be respiratory.

Swimbladder Actinopterygii

Lungs

Ancestral condition: gills present Sarcopterygii

gills

Early ray-finned fishes had lungs! The swimbladder (= gas bladder): a gas inclusion in the body cavity important for buoyancy. It arose in evolution from lungs. The swimbladder (= gas bladder): a gas inclusion in the body cavity important for buoyancy Ray-finned fish (Actinopterygii) phylogeny: broad overview Actinopterygii

Holostei Chondrichthyes Polypterus 1 and relatives Chondrostei

Teleostei

† Cheirolepis

1. Single dorsal fin 2. Fin ray structure: lepidotrichia 3. Scale structure Actinopterygii = ray-fin Actinopterygian synapomorphy #3: scale type Actinopterygian synapomorphy #3: scale type Closely-packed rows of interlocking scales

Bruet, B. J. F., Song, J., Boyce, M. C. and Ortiz, C. (2008). Materials design principles of ancient fish . Materials 7, 748-756. Ray-finned fish (Actinopterygii) phylogeny: broad overview Actinopterygii

Holostei Chondrichthyes Polypterus 1 and relatives Chondrostei

Teleostei

† Cheirolepis

1. Single dorsal fin 2. Fin ray structure: lepidotrichia 3. Scale structure Actinopterygii = ray-fin Early actinopterygian clades

Bichirs and ropefish (Polypteriformes) and (Chondrostei)

Gar (Lepisosteidae) () () and ropefish (Polypteriformes)

Polypterus – ―bichirs‖, ~13+ Bichirs and ropefish (Polypteriformes)

Erpetoichthys – rope fish: 1 species Bichirs and ropefish (Polypteriformes)

• There are ~13 species of and they are considered the most earliest surviving branch of the ray-finned fishes. • They are heavily armored with dermal and a thick layer of ganoid scales. • Occur in and streams in and have a that acts like a paired ventral lung. They will drown if unable to gulp air at the surface. • Because bichirs have paired fleshy pectoral fins and lungs they were formerly classified with the , but are now considered to have evolved these traits independently. • Lung-like gas bladder – air breathing

Paddlefish and sturgeon (Chondrostei -- )

Chondrostei includes forms Acipenseriformes – living sturgeon and paddlefish

Acipenseriformes – sturgeon and paddlefish

• ~25 species of sturgeon and 2 paddlefish species • Cartilaginous lacking vertebral centra • Strongly asymmetrical tail • Bony on sturgeon • Sensory barbels • Mostly freshwater —few marine and anadromous sturgeon • Sturgeon prized for = • Caspian and Black of western Asia • Stocks are collapsing in Asia, and many species endangered • and • Very fecund; mature at a late age

Acipenseriformes -- sturgeon Acipenseriformes -- paddlefish Acipenseriformes -- paddlefish

• Paddlefish: – Lack bony scutes; long – 2 genera (each with 1 species: American (Polyodon spathula) (Psepherus gladius) – American: ―Spoonbill cat‖ – , , and – Planktivore; Long, narrow rakers – Up to 2m in length; 75 kg – Rostrum: electrosensory function? -- rooting through sediment?

Acipenseriformes -- paddlefish

Paddlefish filter feeding Holostei (Lepisosteidae) Holostei Gar (Lepisosteidae) • Gar are medium to large (1-4m) with a distinctive elongated body and long . • They have hard, interlocking, multilayered ganoid scales which provide excellent protection and are similar to the scales of many extinct and actinopterygians. • 7 species • Primitive predators; long jaws with sharp teeth • N. America; 1 species in • All but one freshwater • gar occasionally enters saltwater • Gas bladder/ lung divided internally • Dorsal and anal fins set far back on body • Air breathing Gar (Lepisosteidae) Flood plain dried up (2008) near the Mississippi

Photo by Andrew Carroll Gar (Lepisosteidae) Flood plain dried up (2008) near the

Compare to fossil slab on the MCZ first floor!

Photo by Andrew Carroll Holostei Bowfin (Amia) (Amiiformes)

• There is only one (1) species of bowfin. • Scales are of a single layer of bone as in , but the caudal fin. • Predatory species • Can swim via undulations of the long dorsal fin

• Gulping air for surviving low O2 waters • Males build and defend nests; may defend young until they are 10 cm long

Ray-finned fish (Actinopterygii) phylogeny: broad overview Actinopterygii

Holostei Chondrichthyes Polypterus 1 and relatives Chondrostei

Teleostei

† Cheirolepis

1. Single dorsal fin 2. Fin ray structure: lepidotrichia 3. Scale structure

Actinopterygii = ray-fin Teleost fish phylogeny: broad overview

Otocephala

Elopomorpha ( and )

Osteoglossomorpha (“bony tongues”)

Euteleostei

1. Mobile bone in the 2. Specialized tail Teleostei Actinopterygii = ray-fin Teleost fishes (the Teleostei)

• Tremendous species diversity • The swim bladder is primarily a buoyancy organ • Great diversity of body shapes • Around 30,000 species • 96% of all fishes • ~40 Orders, ~450 families Figure 24.15 • Diversification into all

Feb. 22th Lecture, and discussed in detail as the course progresses Selected key shared derived characters (synapomorphies) for Teleostei Teleostei: 1) Mobile premaxilla bone in head 2) Elongate bones in the tail – uroneurals ( in diagram below)

2 1 Teleostei: (Eels, tarpons) Teleostei: Elopomorpha (Eels, tarpons)

• Eels are the best known members with an amazing life history • Include moray eels, eels, deep ―spiny eels‖ and gulper eels • , , tenpounders (ladyfishes) – good ! • 24 families, around 860 species • United by the presence of a specialized ()

Teleostei: (bony tongues)

• 4 families, around 220 species. • Often exhibit of young • Clown knifefish, , , freshwater fish • fishes (): 201 species, freshwater, African, and these fishes can both generate and detect weak electric fields for communication and prey location Osteoglossomorpha (bonytongues) 2 major groups

Clupeomorpha Ostariophysi

364 species , , , etc. Abundant 8,000 species schooling fishes 28% of all fishes of great commercial 68% of freshwater fishes; importance. , , characins, , , many popular Ear-swimbladder anatomy species, Caudal skeleton anatomy , and gymnotids – South American knifefishes Teleost fish phylogeny: broad overview

Osteoglossomorpha Otocephala (“bony tongues”) Elopomorpha Clupeiformes Ostariophysi (tarpons and eels)

Euteleostei (~ 16,000 species)

1. Mobile premaxilla bone in the skull 2. Specialized tail bones Teleostei Actinopterygii = ray-fin Euteleostei

Freshwater pike

Trout and

mudminnow Euteleostei (, )

Goosefish,

Bat fish : (silversides, , , flying fishes) Euteleostei (, , ) Euteleostei ( and relatives)

Generally useful guides to fish external anatomy and some terminology

8 pages of general information on fish external anatomy and characters to help you learn some basic external fish anatomy and terminology – the last slides in the uploaded lecture Powerpoint file for today.

Please look at these before lab this week, but no need to bring them in with you.

Scanned from: Hastings, P. A., Walker, H. J. and Galland, G. R. (2014). Fishes: A guide to their diversity: Univ of California Press.