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An older English name for bats is flittermouse, which matches their name in other Germanic languages (for example German Fledermaus and Swedish fladdermus), related to the fluttering of wings. Middle English had bakke, most likely cognate with Old Swedish natbakka ("night-bat"), which may have undergone a shift from -k- to -t- (to Modern English bat) influenced by Latin blatta, "moth, nocturnal insect". The word "bat" was probably first used in the early 1570s. [2] [3] The name "Chiroptera" derives from Ancient Greek: χείρ– cheir, "hand" [4] and πτερόν– pteron, "wing". [1] [5] Phylogeny and taxonomy [ edit ] The early Eocene fossil microchiropteran Icaronycteris, from the Green River Formation Evolution [ edit ] Whether or not the analysis of the uncrushed Vielasia skull has settled the echolocation debate about early bats, Prof. Hand hopes that it will inspire further exploration of the fossil record. But an analysis of the evolutionary relationships between these three bat species from Fossil Lake, as well as other fossil and living bats, found that I. gunnelliand I. indexwere most closely related to O. finneyi rather than to other echolocating bats. That “is really unexpected and really weird,” Jones says.
To determine the evolutionary history, or phylogeny of the bats, the researchers compared the new fossils with intact skeletons from six Eocene bat species, as well as with isolated teeth from two other extinct species and with skeletons of living bats. Their results indicated that the newly discovered bat skeletons belong to a never-before-seen species of Icaronycteris, which they named I. gunnelli after the late bat biologist Greg Gunnell. In addition to echolocating prey, bat ears are sensitive to sounds made by their prey, such as the fluttering of moth wings. The complex geometry of ridges on the inner surface of bat ears helps to sharply focus echolocation signals, and to passively listen for any other sound produced by the prey. These ridges can be regarded as the acoustic equivalent of a Fresnel lens, and exist in a large variety of unrelated animals, such as the aye-aye, lesser galago, bat-eared fox, mouse lemur, and others. [89] [90] [91] Bats can estimate the elevation of their target using the interference patterns from the echoes reflecting from the tragus, a flap of skin in the external ear. [85] The tiger moth ( Bertholdia trigona) can jam bat echolocation. [92] [93] Reference: “The oldest known bat skeletons and their implications for Eocene chiropteran diversification” by Tim B. Rietbergen, Lars W. van den Hoek Ostende, Arvid Aase, Matthew F. Jones, Edward D. Medeiros and Nancy B. Simmons, 12 April 2023, PLOS ONE. Prof. Hand says prior to the discovery of this skull—which was among 23 separate fossilized individuals found in the cave belonging to the extinct species Vielasia sigei—only fragments or completely flattened skeletons of early bats had existed in the fossil record. Bats often have a rodentlike or foxlike muzzle, but in many the face has a pushed-in puglike appearance. In the nectar feeders the snout is elongated to house the long extensible tongue. Many bats have a facial ornament, the nose leaf, which consists of skin and connective tissue. It surrounds the nostrils and extends as a free flap or flaps above the nostrils and in front of the face. The complexity and shape of the nose leaf varies with family; its presence correlates with nasal emission of orientation signals. Thus, it is supposed that the nose leaf influences sound output, perhaps by narrowing the beam, but evidence is sparse.In recent years, scientists from the Naturalis Biodiversity Center started looking closely at Icaronycteris index by collecting measurements and other data from museum specimens. Bats are the only mammals capable of sustained flight, as opposed to gliding, as in the flying squirrel. [43] The fastest bat, the Mexican free-tailed bat ( Tadarida brasiliensis), can achieve a ground speed of 160km/h (100mph). [44] Little brown bat take off and flight Simmons NB, Seymour KL, Habersetzer J, Gunnell GF. Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation. Nature 2008; 451: 818–821. pmid:18270539
Other relationships among stem bats recovered in our analyses differed somewhat from previously published phylogenies. Archaeonycteris trigonodon from Germany was recovered as sister to the Icaronycteris + Onychonycteris clade ( Fig 6A) rather than sister to a clade of all bats except Icaronycteris and Onychonycteris, where it was placed in previous analyses (e.g., [ 12, 57]). This placement of Archaeonycteris received only low to moderate support (bootstrap value 37 in analyses including I.? menui and I. sigei and 54 in analyses excluding the previous taxa). Future analyses including other species of Archaeonycteris, Palaeochiropteryx, and Hassianycteris might better resolve relationships among these taxa. While Prof. Hand stops short of concluding that Vielasia sigei used echolocation with 100% certainty, she says the new evidence is compelling. Using CT scans of the specimens, the researchers compared the new species to other bats from the Eocene Epoch, which lasted from around 56 to 34 million years ago. It was the smallest bat from the Green River Formation, and had comparatively short forearms and hindlimbs. Torpor, a state of decreased activity where the body temperature and metabolism decreases, is especially useful for bats, as they use a large amount of energy while active, depend upon an unreliable food source, and have a limited ability to store fat. They generally drop their body temperature in this state to 6–30°C (43–86°F), and may reduce their energy expenditure by 50 to 99%. [111] Tropical bats may use it to avoid predation, by reducing the amount of time spent on foraging and thus reducing the chance of being caught by a predator. [112] Megabats were generally believed to be homeothermic, but three species of small megabats, with a mass of about 50 grams ( 1 + 3⁄ 4 ounces), have been known to use torpor: the common blossom bat ( Syconycteris australis), the long-tongued nectar bat ( Macroglossus minimus), and the eastern tube-nosed bat ( Nyctimene robinsoni). Torpid states last longer in the summer for megabats than in the winter. [113]Ravel A, Adaci M, Bensalah M, Mahboubi M, Mebrouk F, Essid EM et al. New philisids (Mammalia, Chiroptera) from the Early–Middle Eocene of Algeria and Tunisia: new insight into the phylogeny, palaeobiogeography and palaeoecology of the Philisidae. J Syst Palaeontol. 2014;13: 691–709. Snake Skull - Fishing in the ocean, river or pond on the western side of Ginger Island. Special Fishing Spots, indicated by bubbles in the water, have a slightly higher chance of containing Snake Skulls. Swofford D.L. PAUP—Phylogenetic Analysis Using Parsimony (*and other methods), 4.0 [Computer Software and Manual]. Sunderland, MA: Sinauer Associates; 2002. Rietbergen first saw one of the skeletons of Icaronycteris gunnelliin 2017 when he was scrolling through Facebook. “I was like, hmm, this looks a little bit different,” he says. Tabuce R, Antunes MT, Sigé B. A new primitive bat from the earliest Eocene of Europe. J Vertebr Paleontol. 2009;29: 627–630.
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