Introduction to Ichthyology & External Fish Anatomy

Fill-in-the-blank practice flashcards covering introductory ichthyology, key historical figures, fish diversity metrics, functional body shapes, scale structures, fin types, and external anatomy.

According to Berra (2001), a fish is defined as a __________ aquatic chordate with appendages developed as fins, gills as chief respiratory organs, and body usually covered with scales.

poikilothermic

According to Pauly et al. (2014), a fish is a vertebrate that has gills, a body covered with scales, and lives in the __________.

water

Tuna are notable exceptions to typical fish physiology because they are partly __________.

endothermic

Fish first evolved over __________ million years ago (mya).

500

Physiologically, fishes can be found living at temperatures ranging from $-1.8^\circ\text{C}$ to nearly __________.

$$40^\circ\text{C}$$

Fishes inhabit aquatic environments with salinities ranging from $0$ to __________.

$$90\,\text{ppt}$$

Fishes live at ocean depths ranging from $0$ to __________.

$$8,000\,\text{m}$$

By convention, the term "__________" refers to one or more individuals of a single species, whereas "fishes" refers to more than one species.

fish

Estimates for the total number of living fish species worldwide range from __________ to 37,000.

25,000

Jawless fishes belong to the superclass or group known as __________.

Agnatha

Cartilaginous fishes belong to the class __________.

Chondrichthyes

Bony fishes belong to the superclass or group __________.

Osteichthyes

Approximately __________ percent of all fish species live in freshwater.

41%

Approximately __________ percent of all fish species live in sea water.

58%

Only __________ percent of fish species move between freshwater and sea water during their life cycle.

1%

The world's smallest fish and vertebrate is an Indonesian minnow named __________.

Paedocypris progenetica

The smallest commercial fish in the world is sinarapan, scientifically known as __________.

Mistichthys luzonensis

The world's longest cartilaginous fish is the Whale Shark, scientifically named __________.

Rhincodon typus

The longest bony fish in the world is the Oarfish, scientifically named __________.

Regalecus glesne

Body mass for the Ocean Sunfish (Mola mola) can top out at __________.

2300 kg

The Coelacanth, an offshoot of the lineage that gave rise to amphibians, was trawled up in South Africa in the year __________.

1938

Lungfishes can live in a state of dry "suspended animation" for up to __________ years when their ponds dry up.

4

Antarctic fishes keep from freezing because their blood contains __________ proteins that depress their blood's freezing point to $-2^\circ\text{C}$.

antifreeze

In some deepsea anglerfishes, males exist as small parasites permanently fused to the side of the female, living off her __________.

blood stream

The shortest maximum life spans in fishes, around 10 weeks, are found in African killifishes and Great Barrier Reef __________.

pygmy gobies

Ichthyology is the branch of zoology that deals with the study of fish, including their classification, structure, physiology, ecology, and __________.

evolution

Ichthyology has its origins in the writings of __________, who recognized about 117 species of fish.

Aristotle

Peter Artedi is known as the "__________ of Ichthyology."

Father

Carolus Linnaeus adopted and edited Peter Artedi's classification of fishes for the 12 editions of his work __________.

Systema Naturae

Georges Cuvier and Achille Valenciennes authored the comprehensive multi-volume work titled __________.

Histoire Naturelle des Poissons

The eight-volume Catalogue of the Fishes in the British Museum was written single-handedly by __________.

Albert Günther

David Starr Jordan, coauthor of Fishes of North and Middle America, became the founding president of __________.

Stanford University

The three main anatomical regions of a fish body are the head, trunk, and __________.

tail

In fish anatomy, the head is measured from the mouth to the back edge of the __________.

gill cover

In fish anatomy, the trunk is measured from the end of the head to the anus or to the beginning of the __________.

anal fin

The tail region of a fish is measured from the anus to the __________ end (or to the end of the tail fin).

hypural

A streamlined, spindle-shaped body shape seen in fast swimmers like tuna is termed __________.

fusiform

A laterally flattened body shape typical of deep-bodied fishes is termed __________.

compressiform

A dorsoventrally flattened body shape found in skates and rays is termed __________.

depressiform

An elongate, snake-like body shape characteristic of eels is termed __________.

anguilliform

Rover-predators typically possess a streamlined fusiform body, a pointed head with a terminal mouth, and a narrow caudal peduncle tipped with a __________ tail.

forked

Lie-in-wait predators have their dorsal and anal fins placed far __________ on the body to provide maximum thrust during ambush.

back

Deep-bodied fish are compressiform fishes with a body depth usually at least __________ that of the standard length.

one-third

Heavy, enamel-covered ancestral scales found in gars are __________ scales.

ganoid

Elasmoid scales that are smooth, round, flat, and thin are called __________ scales.

cycloid

Elasmoid scales that possess comb-like projections on their posterior field are called __________ scales.

ctenoid

Tooth-like scales with a rough texture found on sharks and rays are called __________ scales.

placoid

The initial growth point on a cycloid or ctenoid scale is called the __________.

focus

Annual growth bands formed on fish scales in temperate regions due to seasonal growth slowdowns are called __________.

annuli

Scales located along the horizontal line of the flank formed by a series of sensory pores are called __________ scales.

lateral line

Scales located from the occiput to the origin of the dorsal fin are called __________ scales.

predorsal

The two sets of paired fins found on fishes are the pectoral fins and the __________ fins.

pelvic

Unpaired fins in fishes include the dorsal fin, anal fin, caudal fin, adipose fin, and __________.

finlets

A caudal fin with unequal lobes where the vertebrae extend into the upper lobe is called a __________ tail.

heterocercal

A caudal fin with equal upper and lower lobes found in most advanced teleosts is called a __________ tail.

homocercal

In ocean sunfishes (molids), the caudal fin is replaced by a hardened bridge between the dorsal and anal fins called a __________.

clavus

A mouth set on the underside of the head, as seen in most sharks, skates, and rays, is described as __________.

inferior

An upturned mouth where the lower jaw extends more anteriorly than the upper jaw is described as __________.

superior

Most bony fish have a flexible gill cover aiding respiration called the __________.

operculum

Sharks, skates, and rays utilize small respiratory openings behind the eyes called __________.

spiracles

The sensory organ system that detects water movement and is visible as a faint line along the body and head is the __________ system.

lateral line

Bottom-feeding fishes such as catfish and suckers use sensory structures called __________ and fleshy lips for taste and touch.

barbels