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State Shell of Texas
Lightning whelk with pear whelk for comparison. Photo credit: TPWD
If we were to measure evolutionary success in the Animal Kingdom by the diversity of species in a given group, insects would take a runaway first, but creeping up in all their slimy glory for second would be the snails. The total number of snail species in the world seems to be a mystery, with estimates ranging anywhere from just under 50,000 to over 80,000 (and a few much higher).
One well-known characteristic of snails is caused by the process of torsion. Simply put, torsion is the modern snail's version of contortionism. Have you ever seen those contortionists in Cirque du Soleil who sit their behinds right on top of their heads? That is a snail's natural position. Its internal organs are all situated above its head in a lump, and this is what the shell covers. In most snails, this lump is coiled, and as the shell grows, it follows this pattern. Thus, the spiral shell that most of us use to recognize snails is grown.
Sometime around the beginning of the Mesozoic era, a lineage of predatory gastropods evolved that eventually gave rise to the modern whelks, a family of sea snails. So what distinguishes a whelk from other sea snails? Not color. While there may not be chartreuse or electric blue whelks, they come in just about every other hue, including hot pink. Not size either. Adult whelks range from less than a half an inch to over two feet. The key is shell shape. Whelk shells are typically biconical and spindle-shaped, widest in the middle and tapering to points at each end. The opening is usually oval and has an operculum (basically a door attached to the snail's foot).
Distinguishing whelks from other snails is not so difficult. Distinguishing whelks from other whelks is another story. Identification books with illustrations are sometimes useful. Then again, whelks of the same species can look drastically different. A whelk's appearance is genetically determined, but the expression of those genetics can be influenced by environmental conditions. For example, the frilly dogwhelk does not always have frills, but if put into an aquarium with a certain snail-eating crab, some chemical given off by the crab will induce frill growth.
Another impediment of whelk ID is an extended juvenile period. Whelks are long-lived snails, thirty or forty years old being an average. They may not reach sexual maturity for several years, though they will reach their adult size sooner. Unfortunately for the avid identifier, a whelk's distinguishing characteristics often don't appear until sexual maturity.
A very small percentage of whelks have a trait that gives them away. If you looked at the top of whelk shells, you'd notice that most spiral in a clockwise, or dextral, direction. A very few spiral counter-clockwise, or sinistral. Less than one percent of whelks display sinistral coiling, and why they do this is a mystery.
One such subspecies of whelk possessing this rare "left-handed" characteristic is Busycon perversum pulleyi, the lightning whelk. Found only on the Western Gulf of Mexico, it possesses one of the largest shells of the region. Busycon, from the Greek word bousycon, meaning large fig, describes the shell's general shape. Its sinistral coiling is reflected in its species name, perversum, which comes from the Latin word perversus, meaning turned the wrong way. The subspecies, pulleyi, was named for Dr. T. E. Pulley, a Texas naturalist and director of the Houston Museum. The common name, lightning whelk, comes from the lightning-like radiating stripes along the shell's sides. B. pulleyi is a subspecies of Busycon sinistrum, though sometimes the two are interchangeable, depending on the author. There is still much debate surrounding the scientific name...
Lightning whelks can reach up to sixteen inches, but are more commonly seen at about eight inches (and it takes them a decade or two to reach that size). While the shell's main purpose is protection, both from the abrasive surf and from predators such as stone crabs, gulls, and other whelks it's outer surface can also be home to smaller creatures, such as barnacles. The whelk and the barnacles have a commensalistic relationship: the barnacles benefit and the whelk is unaffected.
People generally hold a whelk shell vertically, with one pointed end up and the other down, but the whelk crawls with one of these ends, the closed spiraled end, directed backward, and the other pointed forward. This is the business end. While lightning whelks generally stay buried, this long slender end can be seen poking out of the bay floor for hunting purposes. Though they prefer live or freshly dead food, they'll eat almost any animal matter. They prey primarily on bivalves (clams, oysters, scallops, etc). By holding on with its foot and wedging the edge of its shell between the oyster's valves, the whelk can pry open its victim just enough to send in its proboscis, armed with a tongue-like radula.
Unlike a herbivorous mollusk's radula, with rows of relatively flexible teeth meant for grazing, a whelk's radula has three large, scimitar-like teeth. The teeth are replaced regularly as they are used up, similar to shark teeth. The radula is specifically designed for lacerating shell and flesh. Whelks have their radulas (and mouths) at the end of a long proboscis. And by long, I mean looooong. An inch-long whelk can have a foot-long proboscis! This is so they can devour prey down burrows or tubes. With its slicing radula and some digestive enzymes, the whelk makes a clam slurpee and sucks it up.
Lightning whelks spawn annually, mating during the autumn and laying eggs in the early spring. The female lays eggs in long strands of horny, disc-shaped capsules and connects the capsules with a tough cord-like string. Each strand can have 50 to 175 capsules, and each capsule can have 20 to 200 eggs, but only a small percentage of those hatch. These whelks develop a taste for blood early in life. The first hatchlings out of their eggs in the capsule feed on the eggs that have not hatched. The young mature within the capsules, emerging as miniature whelks in late spring. The young whelk's shell grows very quickly as long as food is abundant. Shell growth gradually slows with age, and shell color pales so that the older the whelk, the paler the shell.
Typically, these whelks are found on the bottom of shallow bays, tidal canals, and around jetties, though they also live offshore. They seem to prefer relatively firm bottoms, sand or mud, near shoal grass or turtle grass meadows, usually with a good prey base nearby. Well, who doesn't like to have a grocery store around the corner?
In 1986, Mildred Tate, one of the founders of the Brazosport Museum of Natural Science and its curator of malacology (study of hard-shelled mollusks), began the process of selecting a state shell for Texas. After discussing her aspiration with several Texas legislators, Tate decided to champion the subspecies of whelk, Busycon perversum pulleyi. With this candidate in mind, Tate asked Texas shell clubs for support. In 1987, the state shell resolution was presented to the Texas legislature by Representative John Willy. On April 22, 1987, Governor Bill Clements signed the state shell bill, and the lightning whelk joined the ranks of Texas emblems.
It's fitting since lightning whelks have a history of usefulness. Many Native American tribes believed that the sinistral coiling gave the shells sacred status and harvested them for religious ceremonies. However, the whelks were also eaten, and their shells used as practical tools, such as scrapers, gouges, cups, and bowls. The egg cases were even used by sailors as bath sponges.
Permits are not required for collecting lightning whelk shells in Texas, though there are laws limiting the collection of live lightning whelks, along with other saltwater and freshwater mollusks. There is a daily bag limit of 15 univalve snails, in aggregate, and no more than two each in the daily bag of lightning whelk, horse conch, Florida fighting conch, pear whelk, banded tulip and Florida rock snail. As always, any harvest of live marine animals from Texas coastal waters requires a current Texas fishing license with a saltwater fishing stamp.
In some other world, gigantic seashells hold humans to their ears and listen to the echo of machines.
~ Jeffrey Mcdaniel
One well-known characteristic of snails is caused by the process of torsion. Simply put, torsion is the modern snail's version of contortionism. Have you ever seen those contortionists in Cirque du Soleil who sit their behinds right on top of their heads? That is a snail's natural position. Its internal organs are all situated above its head in a lump, and this is what the shell covers. In most snails, this lump is coiled, and as the shell grows, it follows this pattern. Thus, the spiral shell that most of us use to recognize snails is grown.
Sometime around the beginning of the Mesozoic era, a lineage of predatory gastropods evolved that eventually gave rise to the modern whelks, a family of sea snails. So what distinguishes a whelk from other sea snails? Not color. While there may not be chartreuse or electric blue whelks, they come in just about every other hue, including hot pink. Not size either. Adult whelks range from less than a half an inch to over two feet. The key is shell shape. Whelk shells are typically biconical and spindle-shaped, widest in the middle and tapering to points at each end. The opening is usually oval and has an operculum (basically a door attached to the snail's foot).
Distinguishing whelks from other snails is not so difficult. Distinguishing whelks from other whelks is another story. Identification books with illustrations are sometimes useful. Then again, whelks of the same species can look drastically different. A whelk's appearance is genetically determined, but the expression of those genetics can be influenced by environmental conditions. For example, the frilly dogwhelk does not always have frills, but if put into an aquarium with a certain snail-eating crab, some chemical given off by the crab will induce frill growth.
Another impediment of whelk ID is an extended juvenile period. Whelks are long-lived snails, thirty or forty years old being an average. They may not reach sexual maturity for several years, though they will reach their adult size sooner. Unfortunately for the avid identifier, a whelk's distinguishing characteristics often don't appear until sexual maturity.
A very small percentage of whelks have a trait that gives them away. If you looked at the top of whelk shells, you'd notice that most spiral in a clockwise, or dextral, direction. A very few spiral counter-clockwise, or sinistral. Less than one percent of whelks display sinistral coiling, and why they do this is a mystery.
One such subspecies of whelk possessing this rare "left-handed" characteristic is Busycon perversum pulleyi, the lightning whelk. Found only on the Western Gulf of Mexico, it possesses one of the largest shells of the region. Busycon, from the Greek word bousycon, meaning large fig, describes the shell's general shape. Its sinistral coiling is reflected in its species name, perversum, which comes from the Latin word perversus, meaning turned the wrong way. The subspecies, pulleyi, was named for Dr. T. E. Pulley, a Texas naturalist and director of the Houston Museum. The common name, lightning whelk, comes from the lightning-like radiating stripes along the shell's sides. B. pulleyi is a subspecies of Busycon sinistrum, though sometimes the two are interchangeable, depending on the author. There is still much debate surrounding the scientific name...
Lightning whelks can reach up to sixteen inches, but are more commonly seen at about eight inches (and it takes them a decade or two to reach that size). While the shell's main purpose is protection, both from the abrasive surf and from predators such as stone crabs, gulls, and other whelks it's outer surface can also be home to smaller creatures, such as barnacles. The whelk and the barnacles have a commensalistic relationship: the barnacles benefit and the whelk is unaffected.
People generally hold a whelk shell vertically, with one pointed end up and the other down, but the whelk crawls with one of these ends, the closed spiraled end, directed backward, and the other pointed forward. This is the business end. While lightning whelks generally stay buried, this long slender end can be seen poking out of the bay floor for hunting purposes. Though they prefer live or freshly dead food, they'll eat almost any animal matter. They prey primarily on bivalves (clams, oysters, scallops, etc). By holding on with its foot and wedging the edge of its shell between the oyster's valves, the whelk can pry open its victim just enough to send in its proboscis, armed with a tongue-like radula.
Unlike a herbivorous mollusk's radula, with rows of relatively flexible teeth meant for grazing, a whelk's radula has three large, scimitar-like teeth. The teeth are replaced regularly as they are used up, similar to shark teeth. The radula is specifically designed for lacerating shell and flesh. Whelks have their radulas (and mouths) at the end of a long proboscis. And by long, I mean looooong. An inch-long whelk can have a foot-long proboscis! This is so they can devour prey down burrows or tubes. With its slicing radula and some digestive enzymes, the whelk makes a clam slurpee and sucks it up.
Lightning whelks spawn annually, mating during the autumn and laying eggs in the early spring. The female lays eggs in long strands of horny, disc-shaped capsules and connects the capsules with a tough cord-like string. Each strand can have 50 to 175 capsules, and each capsule can have 20 to 200 eggs, but only a small percentage of those hatch. These whelks develop a taste for blood early in life. The first hatchlings out of their eggs in the capsule feed on the eggs that have not hatched. The young mature within the capsules, emerging as miniature whelks in late spring. The young whelk's shell grows very quickly as long as food is abundant. Shell growth gradually slows with age, and shell color pales so that the older the whelk, the paler the shell.
Typically, these whelks are found on the bottom of shallow bays, tidal canals, and around jetties, though they also live offshore. They seem to prefer relatively firm bottoms, sand or mud, near shoal grass or turtle grass meadows, usually with a good prey base nearby. Well, who doesn't like to have a grocery store around the corner?
In 1986, Mildred Tate, one of the founders of the Brazosport Museum of Natural Science and its curator of malacology (study of hard-shelled mollusks), began the process of selecting a state shell for Texas. After discussing her aspiration with several Texas legislators, Tate decided to champion the subspecies of whelk, Busycon perversum pulleyi. With this candidate in mind, Tate asked Texas shell clubs for support. In 1987, the state shell resolution was presented to the Texas legislature by Representative John Willy. On April 22, 1987, Governor Bill Clements signed the state shell bill, and the lightning whelk joined the ranks of Texas emblems.
It's fitting since lightning whelks have a history of usefulness. Many Native American tribes believed that the sinistral coiling gave the shells sacred status and harvested them for religious ceremonies. However, the whelks were also eaten, and their shells used as practical tools, such as scrapers, gouges, cups, and bowls. The egg cases were even used by sailors as bath sponges.
Permits are not required for collecting lightning whelk shells in Texas, though there are laws limiting the collection of live lightning whelks, along with other saltwater and freshwater mollusks. There is a daily bag limit of 15 univalve snails, in aggregate, and no more than two each in the daily bag of lightning whelk, horse conch, Florida fighting conch, pear whelk, banded tulip and Florida rock snail. As always, any harvest of live marine animals from Texas coastal waters requires a current Texas fishing license with a saltwater fishing stamp.
In some other world, gigantic seashells hold humans to their ears and listen to the echo of machines.
~ Jeffrey Mcdaniel
Where I learned about whelks, and you can too!
A Spineless Column by Ronald L. Shimek, Ph.D.
http://reefkeeping.com/issues/2005-11/rs/index.php
State Handbook & Guide Resources
Texas Symbols, Shell: Lightning Whelk
http://www.shgresources.com/tx/symbols/shell/
TPWD
Lightning Whelk, the State Shell of Texas
http://www.tpwd.state.tx.us/fishboat/fish/didyouknow/whelk.phtml
TPWD
Lightning Whelk (Busycon perversum pulleyi)
http://www.tpwd.state.tx.us/huntwild/wild/species/lwhelk/
Busycon Taxonomic Travail
http://www.jaxshells.org/trava.htm
Texas Marine Species
http://txmarspecies.tamug.edu/invertdetails.cfm?scinameID=Busycon%20sinistrum