Motobdella montezuma
Encyclopedia
Motobdella montezuma is a species
of leech
which is only found in Montezuma Well
, central Arizona
, United States
. It is a nocturnal pelagic predator that feeds almost exclusively on the endemic amphipod Hyalella montezuma
, which it detects using passive sonar and swallows whole.
from Alaska
to Mexico
. However, M. montezuma is only known to occur in a single pool, Montezuma Well
, in the Montezuma Castle National Monument
in Yavapai County, Arizona
.
, leaving an ecological niche
of open-water predator free. Although there are a number of species of invertebrate
s living in the well, the diet of M. montezuma consists almost entirely of the endemic amphipod
Hyalella montezuma
.
, resting at the bottom of the well during the day, when predatory waterfowl
are present. As night falls, the leeches swim towards the surface and hunt amphipods near the surface; this is the only instance of a leech hunting in open water. Prey are detected by passive sonar, and swallowed whole. This pattern of diel vertical migration
by a leech is only known to occur in Montezuma Well.
. Sexual reproduction
results in two individuals fertilizing
each other, and the resulting eggs
are placed in a nutrient-filled cocoon. The cocoon is placed deep enough to avoid the attention of duck
s and other predators, and the eggs hatch into self-sufficient juveniles
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of leech
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...
which is only found in Montezuma Well
Montezuma Well
Montezuma Well , a detached unit of Montezuma Castle National Monument, is a natural limestone sinkhole near Rimrock, Arizona through which some of water flow each day through two underground springs. It is located northeast of Montezuma Castle. The well measures in at across and deep. The...
, central Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It is a nocturnal pelagic predator that feeds almost exclusively on the endemic amphipod Hyalella montezuma
Hyalella montezuma
Hyalella montezuma is a pelagic amphipod. It lives in Montezuma Well, an oasis in central Arizona. It is the only food of the endemic leech Motobdella montezuma....
, which it detects using passive sonar and swallows whole.
Description
Adults of M. montezuma may reach a length of 71 mm (2.8 in) including the suckers at the front and rear.Distribution
M. montezuma is closely related to the genus Erpobdella, which includes species that are widespread across North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
from Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
to Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. However, M. montezuma is only known to occur in a single pool, Montezuma Well
Montezuma Well
Montezuma Well , a detached unit of Montezuma Castle National Monument, is a natural limestone sinkhole near Rimrock, Arizona through which some of water flow each day through two underground springs. It is located northeast of Montezuma Castle. The well measures in at across and deep. The...
, in the Montezuma Castle National Monument
Montezuma Castle National Monument
Montezuma Castle National Monument, located near Camp Verde, Arizona, in the Southwestern United States, features well-preserved cliff-dwellings. They were built and used by the Pre-Columbian Sinagua people, northern cousins of the Hohokam, around 700 AD. Several Hopi clans trace their roots to...
in Yavapai County, Arizona
Yavapai County, Arizona
-2010:Whereas according to the 2010 U.S. Census Bureau:*89.3% White*0.6% Black*1.7% Native American*0.8% Asian*0.1% Native Hawaiian or Pacific Islander*2.5% Two or more races*5.0% Other races*13.6% Hispanic or Latino -2000:...
.
Ecology
Montezuma Well is too small to support a healthy population of fishFish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
, leaving an ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
of open-water predator free. Although there are a number of species of invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s living in the well, the diet of M. montezuma consists almost entirely of the endemic amphipod
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. The name amphipoda means "different-footed", and refers to the different forms of appendages, unlike isopods, where all the legs are alike. Of the 7,000 species, 5,500 are classified...
Hyalella montezuma
Hyalella montezuma
Hyalella montezuma is a pelagic amphipod. It lives in Montezuma Well, an oasis in central Arizona. It is the only food of the endemic leech Motobdella montezuma....
.
Behavior
M. montezuma is nocturnalNocturnal animal
Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal"....
, resting at the bottom of the well during the day, when predatory waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
are present. As night falls, the leeches swim towards the surface and hunt amphipods near the surface; this is the only instance of a leech hunting in open water. Prey are detected by passive sonar, and swallowed whole. This pattern of diel vertical migration
Diel vertical migration
Diel vertical migration, also known as diurnal vertical migration, is a pattern of movement that some organisms living in the ocean and in lakes undertake each day. Usually organisms move up to the epipelagic zone at night and return to the mesopelagic zone of the oceans or to the hypolimnion zone...
by a leech is only known to occur in Montezuma Well.
Life cycle
Like many other leeches, M. montezuma is hermaphroditicHermaphrodite
In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...
. Sexual reproduction
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
results in two individuals fertilizing
Fertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...
each other, and the resulting eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
are placed in a nutrient-filled cocoon. The cocoon is placed deep enough to avoid the attention of duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s and other predators, and the eggs hatch into self-sufficient juveniles
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
.