Toothy Customers


A frequent subject of our writings, the Bowfin

Only vertebrates have true teeth, and the type of teeth they have is indicative of the feeding niche they occupy.  Fishes portray an amazing picture of diversity in teeth and correspondent feeding niches.  Some fish species have no teeth at all and thus rely on their mouths to either crush their prey as in the sturgeon, or simply suck in their prey as in the seahorse and pipefish.  Some have very few teeth, such as the non-parasitic lampreys in adult form, and some have an absolutely terrifying array of teeth such as the pikes and the sharks.


Ventral, exterior view of a Northern Pike jaw

The placement (marginal, medial and pharyngeal) of teeth within a fishes’ mouth is one of the many characters that are used to differentiate fish species.  But a Northern Pike seems to have almost all the surfaces covered:

Esox masquinongy teeth

Disarticulated Northern Pike jaw.  As you might imagine, once the prey fish is caught with the canine teeth and moved into the mouth there is little chance for escape.

Piscivorous fish typically have long, sharp teeth, but some piscivores rely on strategies alternative to their dentition to capture their prey.  The billfishes (marlins, sailfishes and swordfishes) stab and stun their prey with their elongated rostrums, sawfishes slash with a many-toothed rostrum to “collect” their prey.  Electric eels stun prey fishes, while toadfishes, anglerfishes and batfishes use a lure on their snouts or at the end of an extension to attract small fishes and may include a pheromonal attractant.  Such species typically have numerous smaller rows of teeth to grasp and hold their victims.

Fishes also exhibit diversity in the attachment of the teeth in their jaws:  The “Type I” arrangement has a strong mineralized connection between the tooth and and the jaw in bichirs, gars, bowfin, lower teleosts and some higher fishes (or the tooth and the pharyngeal bone in paddlefishes).  The “Type II” arrangement is seen in many teleosts with mineralization incomplete and the tooth connected to the jaw by collagen.  Stomiiformes (the order in which such bizarre, deep sea creatures as dragonfish, marine hatchetfish and viperfish are placed) have the Type III attachment with teeth hinged and depressible for moving prey to the esophagus and then erectible to prevent prey from escaping.  The Type IV attachment has collagen at the posterior part of the tooth base and acts as the hinge with the anterior edge lifting off the base (exposing the pulp cavity) to trap prey, this arrangement is found in pikes, some stomiiforms and higher teleosts.

Some fish groups such as sharks, wrasses, filefishes and triggerfishes exhibit polyphyodontia, the lifelong replacement of teeth.  A new tooth develops in the dental lamina under or behind the existing teeth.  In the sharks, for example, only the front 1 or 2 rows are used for feeding, while teeth develop posteriorly and move anteriorly to replace teeth individually as needed and on a regular basis.  In some shark species this occurs as frequently as every 9-12 days in the sandbar sharks or as infrequently as two to four times a year in the blue shark; with the old teeth drop to the ocean floor.  Exceptions include some like the cookie cutter sharks where the entire upper and lower sets are replaced as units and swallowed.  Piranhas replace one entire side of the teeth on their jaws at one time.  Polyphyodontia is a character that is not unique to fish however; a few mammals (kangaroos, elephants and manatees) and several reptiles replace their teeth too.  Many bony fish are monophydontic and develop only one set of teeth, while most mammals are diphydontic, replacing their teeth only once.

Below are several examples of fish groups or individual species that exemplify the variety in fish dentition and coincident feeding niches.  Forthcoming at the end of the week I’ll post images of these species and their teeth.

Lampreys – start out their life cycle with a toothless mouth suited to filter feeding, and in the parasitic forms develop several circular rows of sharp teeth used for latching onto and rasping a hole in their prey.

Sharks– teeth are triangular and razor sharp, those on the lower jaw have small serrated lateral cusps at the bases for enhanced cutting and tearing that is facilitated with strong jaw musculature and shaking motion of the head or chewing.  Sharks, unlike the higher fishes, do not have pharyngeal jaws associated with their gill baskets.

Lungfish – have a tooth structure unique among the vertebrates: sturdy tooth plates called “Odontodes” that are used for grasping and crushing prey

Gar – rows of small villiform teeth for capturing and holding fishes in their elongated jaws while they manipulate the fish to a headfirst position for swallowing

Bowfin – many sharp caniform, inward pointing teeth on the premaxilla, dentary and maxilla jaw bones for grasping and holding the prey (an extreme example of canine teeth is shown in the African Tigerfish)

Pike – the long, sharply curved caniform teeth on the dentary are a prelude to a villainous array of cardiform teeth  on the premaxillary, basibranchials, last two pharygobranchials, vomer, palatines, and glossohyal bones.

Grass Carp – the heavy pharyngeal teeth of these herbivores are used for shredding algae

Piranha  – teeth are triangular, razor sharp, with small lateral cusps at the bases like sharks

River Redhorse – feed on sand-dwelling mollusks with sturdy teeth on lower pharyngeal jaws (characteristic of all ostariophysans whereas higher teleosts have pharyngeal teeth on lower and upper arches like the redear sunfish) used for crushing molluscs found in the bottom substrates

Flathead Catfish – gulp prey with large, non-protrusible mouth and hold with cardiform teeth, the largest patches of which are on the premaxillary and anteior dentary bones

Largemouth Bass – have limited cardiform teeth on the medial jaw bones, but these are complimented by a large, protrusible mouth for engulfing prey

Ocean Pout – like many molluscivores have strong conical dentition on the anterior portion of their jaws for plucking mollusks from surfaces, and flattened, molariform teeth in marginal or pharyngeal jaws

Triggerfish (incisor-like dentition), Pufferfishes (teeth fused into parrotlike beak) – have powerful oral jaws to remove invertebrate prey (sponges, ascidians, coelenterates and chitons) from surfaces


About the Author: Marc Kibbey is Assistant Curator of the OSU Fish Division at the Museum of Biological Diversity.


A Somewhat Odd Fish Returns to Ohio

Photo by Patrycja Lawryniuk

Pirate Perch (Photo by Patrycja Lawryniuk)

The Pirate Perch’s common name, applied by naturalist Charles C. Abbot upon observation that Pirate Perch in his aquarium ate only other fish (actually they also prey on aquatic insects, annelids and crustaceans); is perhaps less accurately descriptive than its scientific nomenclature Aphredoderus sayanus.  The genus Aphredoderus translates to “excrement throat”, referring to the position of the urogenital vent.  It had been speculated that one of Charles Abbot’s naturalist contemporaries (Jacob Gilliams) named the species after the entomologist Thomas Say as a jibe resulting from some acrimony between the two friends, but evaluation of the meaning of the name reveals that “-anus” is used as a suffix that translates to “belonging to” (

Young Pirate Perch have their vent just in front of the anal fin, but as the fish matures the vent moves forward to just below the juncture of the gills.  Placement of the vent near the throat enables the females to more accurately place their eggs in root masses such as those extending into the water from streamside trees and other woody growth.  As recently as 20 years ago ichthyologists thought that the unusual reproductive morphology supported brooding the eggs in the gills since occasionally females were found with a few eggs therein.  Positioning of the vent is one of the characters (as well as a highly developed lateral line sensory system) shared with cavefishes that is used by ichthyologists to place them in the order Percopsiformes.

The photo below shows a Pirate Perch young-of-the-year (probably about 6 months) with the vent between the pelvic fins at this point in its development.

Pirate Perch young-of-the-year

Pirate Perch young-of-the-year

OSUM 102207 Aphredoderus sayanus showing vent under throat (photo by Marc Kibbey)

OSUM 102207 Aphredoderus sayanus adult showing vent under throat (photo by Marc Kibbey)

Pirate Perch were recorded in the Maumee River drainage of northwestern Ohio as far back as 1875 but disappeared over 60 years ago, primarily from destruction of their habitat.  Demand for productive farmland in that fertile area resulted in development of methods to drain the widespread wetlands, including the practice of channelization.  Channelization, or straightening and dredging; of streams was implemented to facilitate accelerated removal of water from areas inundated during heavy rains.  However this method cleared away aquatic plants, logs, sticks and detritus that was the preferred habitat of the Pirate Perch.  Bulldozing the bank sides removed the undercut bank structure with underhanging root masses that sheltered Pirate Perch and multitudes of other aquatic animals.  Removal of streamside riparian barriers results in siltation of stream bottoms mainly from field tillage and exposes aquatic fauna to pesticides and other chemicals; these impacts compounded to extirpate the Pirate Perch from the state.

Pirate Perch are actually rather tolerant of waters with low oxygen content, preferring low gradient, slow moving and fairly turbid oxbows in streams as well as lakes.  Their extensive distribution is not typical for a fish species with exclusive requirements.  Flourishing populations of Pirate Perch can be found just across the Indiana State line as close as the Tippecanoe and Wabash Rivers, where they are frequently found in farm ditches.

Camp Creek Pirate Perch locality

Camp Creek Pirate Perch locality (photo by Marc Kibbey)

The last Pirate Perch captured in Ohio was caught in 1950.  Extensive sampling by ichthyologists and agencies in the Maumee River watershed failed to find a Pirate Perch until 2013, when the OSUM Fish Division’s sampling crew of Brian Zimmerman and Justin Baker caught one in the Auglaize River near Waynesfield, Ohio.  Imagine the excitement of the two fish enthusiasts!  At first it was thought that a refuge population had proliferated and reoccupied the former Pirate Perch locality as a result of water quality improvements and habitat re-emergence.  But it turned out that the Ohio Division of Wildlife had released up to 200 individuals near that locality as part of a reintroduction effort back in the early 2000’s.  Subsequent trips to the area found more sites with all size classes (very small young to large adults), particularly in smaller tributary streams like Camp Creek with populations that dominated the fish fauna.

Brian and Justin at Camp Creek

Brian and Justin at Camp Creek (photo by Marc Kibbey)

It appears that current conditions in northeastern Ohio, and particularly the Maumee River watershed, have improved or continue to improve to the point where populations of Pirate Perch can be supported in suitable areas.  Recent implementation of no-till and conservation tillage farming practices reduce siltation of waterways, while these combined with conservation of riparian zones help prevent runoff of pesticides into the streams.  Assuming continuation of these practices as well as sewage treatment and other water quality enhancements, the Pirate Perch should be able to reoccupy former distributions and perhaps even spread beyond their historically known range, reassuming their position among Ohio’s fish fauna.

Other interesting aspects of Pirate Perch’s biology include their color: They are fairly attractive (and make good aquarium pets) with iridescent blue (occasionally green, copper or silver) dots along their olive-to-black back and sides.  The males develop a vivid violet hue that complements their black head and sides in spawning condition.  Additionally Pirate Perch may be the only predator known to exhibit sensiochemical crypsis where they employ a range of olfactory cues to obviate avoidance by a diverse assemblage of prey animals, similar to olfactory mimicry (Resitarits and Binckley, 2013).

Photo by Michael Wolfe

Photo by Michael Wolfe


About the Author: Marc Kibbey is Associate Curator of the Fish Division in the Museum of Biological Diversity.

Madtoms of the OSUM Fish Division


Why are the ‘toms mad?  Might have to do with the fact that madtoms are so small and have a hard time competing with their larger con-familials (like Bullhead Catfish and Channel Catfish) for space and food.  But connate with several other small animal species they make up for their small size with a nastily painful poison sting.  Ask any catfish aficionado, or even a neophyte; and they will tell you that they pay careful attention to the sharp spines the catfishes carry at the front of their dorsal and pectoral fins.  Whereas catfishes of the North American Ictaluridae genera other than Noturus lack the actual venom, those other genera do carry bacteria on their spines that can cause infection in the wound. The madtoms secrete their venom in a sac at the base of their pectoral spine.  When threatened the madtoms lock their pectoral spine in an erect position, causing the sac to rupture and releasing the toxin into the water.

Another character that typifies smaller animals is their habit of remaining in the shadows.  Madtom species are quite furtive, hiding under rocks and logs or in crevices including crayfish burrows.   Like other catfish genera they tend to be most active at night.  A savvy madtom collector sallies forth in the darkness with a lantern that attracts the bewhiskered nocturnals like moths to a flame.  The best time for collecting many madtom species is in the cooler months of Autumn, up through December, when they congregate en-masse out in the open.  Madtoms spawn in late spring through summer, so could it be they carry out this excursion in the colder season for the simple reason that many larger predators have moved downstream to deeper waters?

This highly cryptic group of catfishes contains several species with populations that are imperiled to varying degrees.  Some, like Ohio’s Scioto Madtom, are Extinct while many are Endangered, Threatened or Of Special Concern at the State to Federal level.  Noturus species occupy a wide array of habitats but all rely on aquatic insects for their food.  Images of a few of the madtom species vouchered in the OSUM Fish Division are posted below.

OSUM 35531 Noturus flavipinnis 1 of 1 left lateral no label

OSUM 35531 Noturus flavipinnis Yellowfin Madtom.  Several populations of this species are imperiled or extirpated.  Listed as Federally Threatened.  They were successfully reintroduced by Conservation Fisheries International in Tennessee.

OSUM 61379 Noturus munitus 1 of 90 right lateral 3

OSUM 61379 Noturus munitus Frecklebelly Madtom.  Uncommon, declining in some areas of five small, disjunct populations in Gulf Coast drainages.

Noturus flavus 103721

OSUM 103721 Noturus flavus  The Stonecat Madtom is one of the most abundant, as well as the largest madtom species in Ohio with populations across the Mississippi River and Great Lakes drainages in the U.S. and lower Canada, frequently found in faster flowing riffles but also in lakes where there is at least a moderate current.

Stonecat by UT

Noturus flavus Stonecat Madtom, photo by Uland Thomas.

Noturus insignis 50143

OSUM 50143 Noturus insignis Margined Madtom.  Another widespread species with strong populations throughout the Atlantic Slope drainages in northeastern U.S.

Margined Madtom from the Blackwater River Roanoke Drainage VA 15JUL09 by BZ

Noturus insignis Margined Madtom from Blackwater River Virginia, photo by Brian Zimmerman.

Mountain Matom from the Little Miami by UT

Noturus eleutherus Mountain Madtom, photo by Uland Thomas.  Common in some areas but one of Ohio’s State Endangered madtom species.

Noturus miurus 86131

OSUM 86131 Noturus miurus Brindled Madtom.  Relatively common as madtoms go, prefers better oxygenated waters in streams with gravel or sand, likes to hide in leaves and sticks, also inhabits rocky lakeshores.


Noturus miurus Brindled Madtom about to be released/reintroduced from my hand after a trip to Leading Creek in a cooler.

Tadpole Madtom2 from the Maumee River April 2007 by BZ

Noturus gyrinus Tadpole Madtom, photo by Brian Zimmerman.  The Tadpole Madtom occupies quieter waters with sticks and other woody debris, and tolerates muddy, silty areas better than most other madtoms.

Elegant Madtom Noturus elegans from Kentucky photo by Ben Arthur

Noturus elegans Elegant Madtom, from Russel Creek Kentucky.  Photo by Ben Arthur.  Locally common albeit only found in the Green River drainage of Kentucky.  Note the sharp barbs on the rear of the pectoral fin spine that make it particularly hard to remove catfishes from a net!


About the Author: Marc Kibbey is Assistant Curator of the OSU Fish Division at the Museum of Biological Diversity.

A State Treasure: Gone But Not Forgotten

Although Ohio has some 180 freshwater fish species living in the State’s lakes and streams, it is home to only one endemic species:  the Scioto Madtom, Noturus trautmani.

In November of 1943, when OSU Museum of Zoology Curator Milton Trautman captured the little catfish from his favorite locality, he recognized that it was not a form that he’d encountered during his multitudinous collecting trips.

OSUM 5914 Noturus trautmani right lateral 3 no label


OSUM 5914 – Noturus trautmani


These fish, which were later described and named in his honor, are similar to the Elegant Madtom, Noturus elegans.  A study carried out by W. Ralph Taylor (1969) recognized those similarities in describing the Scioto Madtom and placing it close to the Elegant Madtom phylogenetically (substantiated in a 2009 publication by Egge and Simons), although osteologically the two are quite different.  Icthyologists postulate that the Scioto Madtom may have speciated from an elegans population following a glaciation event.

OSUM 9575 Noturus trautmani C&S 1 with arrows pointing to anterior pectoral spine and humeral process



OSUM 9575 – Noturus trautmani – Cleared and Stained preparation.




Note arrows showing anterior pectoral fin spines and humeral process significantly shorter than those characters on the Noturus elegans specimen below (vertebral counts also separate the two species)

OSUM 18913 Noturus elegans head and trucnk C&S microscope shot with arrows pointing to anterior pectoral spines and humeral process



OSUM 18913 – Noturus elegans – Cleared and Stained preparation.



Although anatomical features and a unique color pattern were used to justify recognizing the Scioto madtom as a distinct species, several local fish enthusiasts have wondered whether the Scioto Madtom population were simply hybrids between the Stonecat Madtom Noturus flavus, which resembles the Scioto Madtom in coloration and in possessing a low adipose fin, and Noturus stigmosus, which has long pectoral barbs and humeral processes but strong saddle markings on its body. However, no instance of hybridization between these species has been reported, although other hybridizations are reported among madtoms.

The length of Big Darby Creek from which Milton captured almost all of what was later called the Scioto Madtom are recorded in our catalog book as 100-200’ above the State Route 104 bridge.  The first Scioto Madtom specimens collected were found in Riffle No. 3 of a series of four riffles and runs called “Trautman’s Riffle”.

Scan of drawing of Trautmans Riffle from Ohio Conservation Bulletin 1963


Drawing of Trautman’s Riffle from Gilfillan, Merrill C.  1963.  The Fishes of Trautman’s Riffle.  Ohio Conservation Bulletin, Vol. 27, No. 5.  pp. 22-24.


20140711BigDarbyCkRM3_4Trautmansriffle photo by Anthony Sasson


Trautman’s Riffle on Big Darby Creek upstream of State Route 104. Photo by Anthony Sasson of The Nature Conservancy.



Trautman and his successor in the OSUM Fish division, Ted Cavender, both searched extensively for populations of Scioto Madtoms outside of the type locality. These collections led to the discovery of other species of madtoms, but failed to unearth another population of Scioto Madtoms (the last one collected was in Autumn of 1957).

My introduction to Trautman’s Riffle didn’t happen until the mid-1990’s.  Although I’d spent many a day on lakes, reservoirs and rivers fishing with my grandfathers, my fishing experiences had not included seining until I took Ichthyology at OSU with Ted Cavender.



Ted Cavender (center), OSUM Curator 1970-2005, with his OSU Biology of Fishes class at the Scioto River fishing access just east of the Big Darby Creek confluence, ca. 2002.


In the 20 years since this introduction, I have personally observed some of the riffles in the vicinity of Trautman’s Riffle moving, due to the “flashy” flooding character of the stream.  One such riffle downstream from Trautman’s Riffle headed up under the State Route 104 bridge to about 50 yards downstream, and some of the structure appears to have moved down to an area at the next major bend in the stream’s course.  Despite the dynamism of the Big Darby in this stretch, Trautman’s Riffle remains mostly intact, although it seems to have been better defined when Milton collected the Scioto Madtom back in the 1940’s and 1950’s.

The increased propensity for flooding and the increased impact of these floods in Big Darby Creek is due at least in part to anthropogenic changes to the topography of the watershed as well as to its hydrology.  Clearing of the riparian area right up to the edge of the creek removes the trees, brush and grasses that serve as a natural filter for pollutants like smothering silt loads from farm field tillage and removes tree roots that hold the upper layer of dirt and enable the stream to create undercut areas where fish hide.  A natural riparian buffer also furnishes woody debris that falls into the stream, creating more habitat and egg laying areas for fish.

Could a flooding event, other weather conditions, or impacts such as siltation of substrates from agricultural tillage, have affected the Scioto Madtom population severely enough that they were unable to propagate?  A catastrophic release of silage on Little Darby Creek in the 1980’s wiped out an otherwise healthy population of Least brook lampreys at Mechanicsburg Ohio, demonstrating the potential impact of a rare event.

Since the Scioto Madtom was only ever found in a very small population, and subsequently not found for many years, the species was listed for decades as an endangered species. Several governmental and private monitoring agencies have sampled the site and conducted exhaustive sampling of other localities in the Scioto River and other major Ohio River tributaries, especially those that focused exclusively on habitats where Madtoms could be expected.  One such effort was funded by the U.S. Fish and Wildlife Service. The 3-year project to sample the major Ohio River tributaries within the state for Madtoms turned up nets full of Northern Madtoms, Mountain Madtoms and Stonecat Madtoms, but unfortunately no Scioto Madtoms.  Because of the lack of results despite intensive expert searches, many suspected it was extinct. The U.S. Fish and Wildlife Service and the Ohio Division of Wildlife concur, and have recently declared the Scioto Madtom extinct. This new listing notwithstanding, we can’t help but keep an eye out every time we are in suitable habitat for the elusive, endemic, endangered Scioto Madtom.


About the Author: Marc Kibbey is Assistant Curator of the OSU Fish Division at the Museum of Biological Diversity.