Zoology

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Entries - Entry Category: Zoology - Starting with L

Lampreys

aka: Jawless Fishes
Lampreys are primitive jawless fishes in the Family Petromyzontidae, Order Petromyzontiformes, Class Petromyzontida, and Superclass Cyclostomata. The common name “lamprey” is almost certainly derived from the Latin lampetra, which likely means “stone licker” (lambere “to lick” + petra “stone”). They are also sometimes called lamprey eels, although they are not eels. Instead, lampreys are the direct descendants of the first armored jawless fishes or ostracoderms, which first appeared over 400 million years ago during the Silurian and Devonian periods. Today, there are only two remaining groups of jawless fishes: the lampreys and the hagfishes (Order Myxiniformes, Class Myxini). Hagfishes, which resemble lampreys, are the sister taxon of lampreys based on DNA evidence. There are about forty-two living lamprey species in …

Leeches

Leeches are segmented worms belonging to the Phylum Annelida, Class Clitellata, Subclass Hirudinida. Leech classification is primarily based on the presence or absence of setae (bristles) and the morphology of the mouth, proboscis (feeding organ), jaws, and suckers. Leeches are thought to have evolved from certain oligochaete worms; however, the systematics and taxonomy of leeches are in need of review. Twenty-two species within five families (Erpobdellidae, Glossiphoniidae, Haemopidae, Hirudinidae, Piscicolidae) have been reported from northern Arkansas, but, as of 2018, there are no summaries of leeches from the southern part of the state. Leeches are bilaterally symmetrical, with thick muscular bodies. Usually, they are dorsoventrally flattened and segmented. Some leeches are long and worm-like (ranging in size from about seven …

Lice

Lice belong to the Phylum Arthropoda, Class Insecta, Order Phthiraptera, with four suborders: Anoplura (sucking lice), occurring on mammals exclusively; Rhynchophthirina, parasites of elephants and warthogs; Ischnocera, which are mostly avian lice, though one family parasitizes mammals; and Amblycera, a primitive suborder of chewing lice, widespread on birds but also infesting South American and Australasian mammals. The chewing lice (suborders Rhynchophthirina, Ischnocera, and Amblycera) were previously combined in the order Mallophaga, which did not reflect natural grouping. There are nearly 5,000 described species of lice, with about 4,000 being parasitic on birds and 800 on mammals, within about twenty-six families of described species of phthriapterans. Many mammal species can be infested by sucking lice, including seals and walruses. These “marine …