Neovison macrodon

The sea mink (Neovison macrodon) is a recently extinct species of carnivorous mammal of the family Mustelidae, which lived on the east coast of North America. It was closely related to the American mink (Neovison vison), with debate over whether or not it should be considered a subspecies of the American mink (Neovison vison macrodon) or its own species. The main justification for a separate species designation is the size difference between the two minks, but other distinctions have been made, such as their redder fur. The only known remains are fragments that were unearthed in Native American shell holes. Its actual size is speculative, based mainly on the remains of teeth.

The sea mink was described for the first time in 1903, after its extinction; Information regarding their external appearance and habits is derived from speculation and accounts made by fur traders and Native Americans. It may have exhibited similar behavior to the American mink, for example it probably practiced polygynandry, was territorial and had a similar diet, but oriented more towards the sea. It was probably found on the coasts of New England and the Maritime provinces of Canada, but its expansion may have been further south during the last glacial period. However, their area of occupation may have been restricted only to the coasts of New England, specifically the Gulf of Maine, or only to nearby islands. The largest of the minks, the sea mink, was highly coveted by fur traders and this caused its extinction in the late 1800s or early 1900s.

Taxonomy and etymology

The sea mink was first described as Lutreola macrodon, distinct from the American mink, by Daniel Webster Prentiss, a physician and ornithologist, in 1903 after its extinction. Prentiss based her description of him on skull fragments that were found in Native American shell holes. Most of the remains, almost all skull fragments, have come from shell pits, but a complete specimen has never been found.

It has been debated whether the sea mink was its own species, or a subspecies of the American mink. Those who argue that the sea mink was a subspecies often refer to it as Neovison vison macrodon. A study conducted in 1911 by Frederic Brewster Loomis, an American paleontologist, concluded that differences between the American mink and sea mink were too small to justify classifying the latter as a separate species and calling it Lutreola vison antiquus. A 2000 study by Mead et al. refuted Loomis by stating that the size range for the largest sea mink specimen was greater than that of the largest American mink specimen, making it a separate species. But a 2001 study by Graham concluded that the difference of size was insufficient evidence to classify the sea mink as a species and that it should be considered a subspecies. Graham hypothesized that the size difference was caused by environmental factors. Graham further reported that Mead had assumed that the smaller mink specimens were American mink, and the larger mink specimens that were outside the range of the American mink were sea mink. This may have been a case of sexual dimorphism in which all specimens were sea minks, with the largest being male and the youngest being female. A 2007 study compared the teeth of the sea mink with those of the American mink and concluded that they were distinct enough to be considered separate species.

The taxonomy of minks was revised in 2000, resulting in the formation of a new genus, Neovison, which includes only the sea mink and the American mink. Previously, both minks were classified in the genus Mustela. The species name macrodon means "big teeth." According to Richard Manville, a naturalist who calls the sea mink a subspecies, its closest living relative is the common mink (N. v. mink), which also lives in the New York area. England.

The fur traders who hunted it gave the sea mink several names, including the water marten, the red otter, and the catfish marten. Possibly the first description of this species was made by Humphrey Gilbert in the late 1500s as 'a fish like an English greyhound', which is a reference to its affinity with the sea and its body shape and gait, which were apparently similar to an English greyhound. It is possible that the fisher got its name from being mistakenly identified as a sea mink, which was also known as the fisher by fur traders. The Abenaki Amerindian tribe referred to it as "mousebeysoo", which means "wet thing". It was named "sea mink" because it was always seen near the coast by fur traders; and because of this the American mink was often called 'wood mink'.

Distribution

The sea mink lived in the intermareal area with volatile tides.

The sea mink was a marine mammal that probably lived around the rocky coasts of New England and the maritime provinces of Canada until it was hunted to extinction in the late 1800s. Most sea mink remains are unearthed off the coast of Maine. Although it is speculated that they inhabited Connecticut and Rhode Island, they were commonly caught along the shores of the Bay of Fundy (in the Gulf of Maine), and it is said that they formerly existed on the southwestern coast of Nova Scotia. There were reports of unusually large mink pelts being collected regularly from Nova Scotia. The bones of the specimens unearthed in Middleboro, Massachusetts, were dated to be 4,300± 300 years old, 19 kilometers (11.8 mi) of salt water. The sea mink may have been in that area by traveling up rivers, or may have been brought there by Native Americans. The latter is more likely since no other mink remains have been found between Casco Bay in Maine and southeastern Massachusetts. Sea mink bones have been unearthed in Canada, although these may have been brought there by Native Americans; The sea mink may never have inhabited Canada. The rugged coasts of the Downeast region of Maine may have represented a more northern barrier to their range. Mead concluded that only American minks inhabited the mainland and that sea minks were restricted to coastal islands. If this is the case, then all remains found on the continent were brought there. Graham challenged that hypothesis, stating that it is unlikely that all sea mink specimens originate from one population.

During the last glacial period, ending 12,000 years ago, the sea mink's range may have extended south of the Gulf of Maine. It is possible that it evolved there, as Maine at that time would have been covered in glaciers, although the oldest known specimen only dates back about 5,000 years; This could be due to rising sea levels – older remains may have been submerged. Alternatively, the sea mink may have evolved after the last glacial period and filled a new niche.

Description

Since the sea mink has only been described with fragmentary remains, its appearance and behaviors are not well documented. Its relatives and descriptions by fur traders and Native Americans give a general idea of the appearance of this animal and its ecological roles. Accounts from Native Americans in the New England regions and the Atlantic provinces of Canada reported that the sea mink had a fatter body than the American mink. The naturalist Joseph Banks is thought to have found this animal in 1776 in the Strait of Belle Isle, and described it as being slightly larger than a fox, as it had long legs and a tail that was long and tapered at the end, like an English greyhound.

The sea mink was the largest of the minks. Since only fragmentary remains of the sea mink exist, most of its external measurements are speculative and rely only on dental measurements. In 1929, Ernest Seton, a wildlife artist, concluded that the probable dimensions for this animal are 91, 4 centimeters (35.984 in) from head to tail, with a tail measuring 25.4 centimeters (10 in). A possible mounted specimen of the sea mink that was collected in 1894 in Connecticut measured 72 centimeters (28.346 in) from head to tail and the tail was 25.4 centimeters (10 in). A 1996 study found that this specimen was a large American mink or possibly a hybrid. The specimen was described as having thick fur that was reddish or tan in color but much of this was probably discolored by age. It was darker on the tail and hind legs, with a 5-by-1.5-centimeter (2 by 0.6 in) white patch between the forearms. He also had white spots on his left forearm and groin region.

The type specimen was collected by Prentiss and Frederick William True, a biologist, in 1897 in Brooklin, Maine. Its remains consist of a maxilla, parts of the nasal bone, and the palate. All the teeth are present on the right side, and the left side consists of the incisor teeth and one premolar tooth. Except for one chipped canine tooth, all teeth are in good condition. The specimen is larger than the Alaska mink, as the average distance between the last incisor to the first premolar is 2.8 centimeters (1.1 in) in the Alaska mink, while that distance is 3 centimeters (1.1 in). 2 in.) in specimen type. The nasal bone has a more abrupt rise, and the carnivorous teeth make a more acute angle with the gums than those of the common mink.

These minks were large and strongly built, with a low sagittal crest and processes on the frontal bone near the orbital cavities that were short and wide. In fact, the most notable feature of the skull was its size and it was larger than all other minks, boasting a broad snout, large nostrils, large antorbital fenestrae (openings in the skull in front of the eye), and large teeth. Its large size was probably caused by its coastal habitat, as the largest extant subspecies of the American mink, the Alaskan mink (N. v. nesolestes), inhabits the Alexander Archipelago in Alaska, a region with a habitat similar to the Gulf of Maine. Mead, who concluded that sea mink were restricted to nearby islands, suggested that their large size was caused by island gigantism. Since almost all members of the subfamily Mustelinae exhibit sexual dimorphism, male minks were probably larger than females. Since butcher's teeth were broader and blunter than the American mink, they may have crushed hard shells more frequently.

Behavior

Since marine species often play an important role in their ecosystem, it is possible that the sea mink was an important intertidal predator. It may have had a similar diet to the American mink, and may have eaten seabirds, seabird eggs, and hard-bodied marine invertebrates, but in larger proportions. Fur traders reported that sea mink dens had two entrances, and were made of rocks that were piled up by the waves. The remains of Myoxocephalus octodecemspinosus (a sculpin) and Zoarces americanus (a smallpox) were the most common around their lairs, and white-lipped snails (Cepaea hortensis) were also found. reported that they were part of their diet. Their diet, which was highly dependent on the sea, may have increased their size. According to fur traders, the sea mink was nocturnal and resided in caves and rock crevices during the day. Due to the overlap between the ranges of the American mink and the sea mink, it is possible that they hybridized. Although not a truly marine species as it was restricted to the coast, the sea mink was unusually aquatic compared to other members of the Musteloidea, being, apart from otters, the most aquatic member of the taxon.

Like other minks, individual minks may have maintained territory and since males were larger and required more food, males may have had greater territorial claims. Likewise, their large size may have allowed the males to target larger prey than the females, and they may have had to defend the females during mating season. Like other weasels, the sea mink was probably polygonous, and both sexes mated with multiple individuals.

Exploitation and extinction

The sea mink was pursued by fur traders for its large size, which made it more desirable than other species of mink that were further inland. Unregulated trade eventually led to their extinction, which is thought to have occurred between 1860 and 1920. The sea mink was rarely sighted after 1860. The last two recorded killings took place in 1880 near Jonesport, Maine and in Campobello Island in New Brunswick in 1894, although the latter is speculated to have been from large American minks. Fur traders made traps to capture sea mink and also chased them with dogs, although they rarely caught them. If a sea mink escaped into a small hole in the rocky ledges, it was dug by hunters with shovels and crowbars. If he was out of reach of the hunters, he was shot and then retrieved using an iron bar with a screw at the end. If it hid, it was smoked and suffocated. Their nocturnal behavior may have been caused by fur traders who hunted them in the day.

Since the remains of the neuroskulls found in shell holes are broken and many of the bones found exhibit cut marks, it is assumed that the sea mink was hunted by Native Americans for food, and possibly for trade and ceremonial purposes. A study investigating remains in the Penobscot Bay shell piles reported that sea mink skulls were more intact than those of other animals found, implying that they were placed there specifically. Males were collected more often than females.