Two species are described in the literature: A. ramidus, which lived about 4. 4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5. 6 million years ago ( late Miocene ).

Two Bacillus species are considered medically significant: B. anthracis, which causes anthrax, and B. cereus, which causes a foodborne illness similar to that of Staphylococcus.

Two species of hamster belonging to the genus Phodopus, Campbell's dwarf hamster ( Phodopus campbelli ) and the Djungarian hamster ( Phodopus sungorus ), and two of the genus Cricetulus, the Chinese striped hamster ( Cricetulus barabensis ) and the Chinese hamster ( Cricetulus griseus ) have a dark stripe down their heads to their tails.

Two of the three sampled species within Cricetulus represent the earliest split.

Two dwarf species, named Orcinus nanus and Orcinus glacialis, were described during the 1980s by Soviet researchers, but most cetacean researchers are skeptical about their status, and linking these directly to the types described below is difficult.

Two of his works, the first edition of the Species Plantarum ( 1753 ) for plants and the tenth edition of the Systema Naturae ( 1758 ), are accepted as among the starting points of nomenclature ; his binomials ( names for species ) and his generic names take priority over those of others.

Two kinds of lizards, the Mourning Gecko ( Lepidodactylus lugubris ) and Snake-eyed Skink ( Ablepharus boutonii ) are present on Malden, together with brown libellulid dragonfly and large colonies of Sooty Terns and other migratory seabirds ( nineteen species in all ).

Two examples are kamacite and taenite, which are found in iron meteorites ; these species differ by the amount of Ni in the alloy ; kamacite has less than 5 – 7 % nickel and it's a variety of native iron, whereas the nickel content of taenite ranges from 7 – 37 %.

* Two new fossil penguin species found in Peru

Two planarian species have been used successfully in the Philippines, Indonesia, Hawaii, New Guinea, and Guam to control populations of the imported giant African snail Achatina fulica, which was displacing native snails.

Two water molecules are oxidized by four successive charge-separation reactions by photosystem II to yield a molecule of diatomic oxygen and four hydrogen ions ; the electron yielded in each step is transferred to a redox-active tyrosine residue that then reduces the photoxidized paired-chlorophyll a species called P680 that serves as the primary ( light-driven ) electron donor in the photosystem II reaction center.

Two species of Pteranodon are traditionally recognized as valid: Pteranodon longiceps, the type species, and Pteranodon sternbergi.

Two species, P. orogensis and P. orientalis, are not pteranodontids and have been renamed Bennettazhia oregonensis and Bogolubovia orientalis respectively.

Two endangered species of birds are found here: the California least tern and the California clapper rail.

Two categories are at the species level ; two, at the individual level.

* Two different species of three-spined sticklebacks in each of five different lakes

Two uteri usually form initially in a female fetus, and in placental mammals they may partially or completely fuse into a single uterus depending on the species.

Two species are currently recognized, although others have been assigned in the past.

Two other species of small turtles are the American mud turtles and musk turtles that live in an area that ranges from Canada to South America.

Two species of Hippopotamus, the European Hippopotamus ( H. antiquus ) and H. gorgops ranged throughout continental Europe and the British Isles.

Two other species, Bdellovibrio starrii and Bdellovibrio stolpii, have been moved to a separate genus Bacteriovorax.

Two submarines of the United States Navy have been named USS Tang, after the tang, or surgeonfish, especially of the several West Indian species.

( 1984 ) Two new species of Acanthocephalan Parasites of marine fishes from Bay of Bengal off Purri coast Orissa.

:* The Hippopotamus Marsh: Lords of the Two Lands, Volume One ( 1998 )

There are three species of landbirds present, one of which is an endemic subspecies of the Malagasy White-eye ( Zosterops maderaspatanus voeltzkowi ).

* Malagasy Mountain Mullet, Acentrogobius therezieni, a species of fish in the Gobiidae family endemic to Madagascar

Three species of Malagasy Hippopotamus became extinct during the Holocene on Madagascar, one of them within the past 1, 000 years.

A sister species of the pygmy hippopotamus may have been the little-studied Malagasy pygmy hippopotamus ( Hexaprotodon madagascariensis or Hippopotamus madagascariensis ), one of three recently extinct species from Madagascar.

There were also several species of pygmy hippo on the island of Madagascar ( see Malagasy hippopotamus ).

Genetic evidence from several nuclear and mitochondrial genes argues against placing Malagasy galidiines in the mongoose family ; instead, these species are more closely related to other Madagascar carnivorans, including the fossa and Malagasy civet .< ref > As a result, this subfamily was moved from Herpestidae to Eupleridae.

Oplurus is a genus of Malagasy iguanian lizard, most of which are rock-dwelling terrestrial species.

When Mausfeld and others split Mabuya in 2002, they resurrected Euprepis for the group including African and Malagasy species and the Noronha skink and also listed Lacerta punctata as the type species, considering all previous type designations invalid.

Some sources also list a genus Hypogeomys, with one species, but this genus name is normally used for the Malagasy Giant Rat, which belongs to the family Nesomyidae.

In the Menabe region of Madagascar, a biodiversity hotspot of great importance, the Trust is working with a cluster of endangered species, including the Malagasy Giant Rat, Flat-tailed Tortoise, Madagascar Big-headed Turtle, Narrow-striped Mongoose and Madagascar Teal.

There is a closely related species in Madagascar, the Madagascar Malachite Kingfisher, or Malagasy Kingfisher, ( Alcedo vintsioides ).

The species is named for its mouse-like size and coloration and is known locally ( in Malagasy ) as tsidy, koitsiky, titilivaha, pondiky, and vakiandry.

In many cases, these Malagasy names are also used for other visually indistinguishable mouse lemur species that live within its range.

The Madagascar national football team, nicknamed Barea ( a species of Zebu that is depicted on the country's coat of arms ), is the national team of Madagascar and is controlled by the Fédération Malagasy de Football.

In some species, for example the Malagasy Paradise Flycatcher, the males have two or more colour morphs.

The common name is the same as the generic name of the Malagasy civet ( Fossa fossana ), but they are different species.

The species name, fontoynontii ( sometimes spelled fontoynonti ), was selected in honor of Antoine Maurice Fontoynont, the president of the Académie Malgache ( Malagasy Academy ) at the time.

African and Asian species are also pollinated by resin-collecting megachilid bees, but Malagasy species are pollinated by pollen-feeding beetles and pollen-collecting bees.