| Synemporion Temporal range: | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Chiroptera |
| Family: | Vespertilionidae |
| Genus: | † Synemporion Ziegler et al., 2016 |
| Species: | †S. keana |
| Binomial name | |
| †Synemporion keana Ziegler et al., 2016 | |
Synemporion keana is an extinct species of bat which lived in what is now Hawaii from at least 320,000 years ago to around 2,100 years ago. It is the only species in the genus Synemporion. [1] [2]
The first fossils of Synemporion keana were found in a lava tube on Maui in 1981. [2] As of 2016, fossils from at least 110 unique individuals of this species have been uncovered. [1]
The genus name Synemporion is derived from Ancient Greek "synemporos" meaning "fellow traveler or companion." The authors chose this genus name to reflect the fact that the genus traveled on the tectonically active Hawaiian Islands along with the Hawaiian hoary bat (Aeorestes semotus). The species name "keana" comes from Hawaiian " ke " meaning "the" and " ana " meaning "cave." The name keana references the fact that the holotype was discovered in a lava tube. [1]
The relationship of Synemporion relative to other vesper bat genera is inconclusive. Researchers have been unable to extract its DNA from fossils, which is the only reliable way to examine phylogenetic relationships in this family of bats. It is unclear if Synemporion colonized the Hawaiian Islands from the Old World or the New World; most likely it belonged to one of the tribes of subfamily Vespertilioninae which make up the bulk of vesper bats but this is simply assumed because the minor subfamilies of vesper bats as well as the Vespertilioninae tribes were all well distinct from each other already by the time Synemporion became a separate lineage. But few skeletal characteristics are known to reliably indicate relationships among the vesper bats, so all that can be said at present is that it lacks obvious traits suggesting it belongs to one of the minor vesper bat subfamilies. [1]
It was a relatively small species of bat, with linear measurements about 25% smaller than the Hawaiian hoary bat which weighs 10-15 grams and has a wingspan of around a dozen cm. Notably, the skull's muzzle is somewhat more narrow than in its fellow species, and the nasal region is markedly concave (instead of barely convex in A. semotus), resulting in the skull having a pronounced snout. How its nose looked in life is unknown; the Vespertilionidae generally produce echolocation sounds with the voicebox and not with the nose, and consequently lack the elaborate ultrasound-focusing nose appendages of bats that use the latter technique. To what extent this applied to Synemporion is not clear; most of the tribes it may belong to contain a few species with nose or upper jaw appendages. These are rarely as elaborate as those of horseshoe bats (Rhinolophidae), for example, and are sometimes related to sexual selection rather than echolocation; there is no indication that Synemporion had marked sexual differences, and altogether its skull shape is not too different from that of Australasian big-eared bats (Nyctophilus). [1]
One notable difference from all vesper bats it was compared with, however, is the sagittal crest which seems to be completely absent in Synemporion. The teeth are more delicate than in the Hawaiian hoary bat, especially so in the lower jaw; otherwise their dentitions differ little. Its dental formula was 1.1.1.33.1.2.3 or 1.1.2.33.1.2.3 for a total of 30 or 32 teeth. The missing sagittal crest combined with the weaker dentition makes it almost certain that Synemporion could not nearly bite as hard as A. semotus, and thus ate different, smaller and/or more soft-bodied prey. [1]
S. keana lived on at least 5 Hawaiian islands: Kauaʻi, Oʻahu, Molokaʻi, Maui, and Hawaiʻi. [1]
While it is unknown when Synemporion first arrived in the Hawaiian islands, the oldest known fossils are from 320,000–400,000-year-old deposits on Oahu. One bone from another site on Oahu has been dated at 2718–2479 years ago, but some undated remains indicate that S. keana survived until more recently; relatively well-preserved skeletons in a wet, dynamically active cave on Molokai suggest that the bat may have survived until as recently as a few thousand years ago. [1]
Like many Hawaiian birds, the extinction of Synemporion keana may have been caused by humans, either directly or indirectly. Possible causes of its extinction include destruction of Hawaiian lowland dry forests and introduction of predators such as rats. [1]
Vespertilionidae is a family of microbats, of the order Chiroptera, flying, insect-eating mammals variously described as the common, vesper, or simple nosed bats. The vespertilionid family is the most diverse and widely distributed of bat families, specialised in many forms to occupy a range of habitats and ecological circumstances, and it is frequently observed or the subject of research. The facial features of the species are often simple, as they mainly rely on vocally emitted echolocation. The tails of the species are enclosed by the lower flight membranes between the legs. Over 300 species are distributed all over the world, on every continent except Antarctica. It owes its name to the genus Vespertilio, which takes its name from a word for bat, vespertilio, derived from the Latin term vesper meaning 'evening'; they are termed "evening bats" and were once referred to as "evening birds".
Located about 2300 miles (3680 km) from the nearest continental shore, the Hawaiian Islands are the most isolated group of islands on the planet. The plant and animal life of the Hawaiian archipelago is the result of early, very infrequent colonizations of arriving species and the slow evolution of those species—in isolation from the rest of the world's flora and fauna—over a period of at least 5 million years. As a consequence, Hawai'i is home to a large number of endemic species. The radiation of species described by Charles Darwin in the Galapagos Islands which was critical to the formulation of his theory of evolution is far exceeded in the more isolated Hawaiian Islands.
The hoary bat is a species of bat in the vesper bat family, Vespertilionidae. It lives throughout most of North America.
The Hawaiian hoary bat, also known as ʻōpeʻapeʻa, is a species of bat endemic to the islands of Hawaiʻi. Whereas the mainland hoary bat is found throughout North America, the Hawaiian hoary bat is distributed only among the major volcanic islands of Hawaiʻi, making it the only extant and native terrestrial mammal in the state; although some studies also posit that the mainland hoary bat lives in sympatry on the Hawaiian Islands alongside the Hawaiian hoary bat, this has been disputed. The Hawaiian hoary bat was officially named the state land mammal of Hawaiʻi in 2015. It is a federally listed endangered taxon of the United States.
Schlieffen's serotine, also known as Schlieffen's bat or Schlieffen's twilight bat, is a species of vesper bat found in Africa. It has been placed in numerous genera since its first description in 1859, but morphological and genetic studies have confirmed it as the only species in the genus Nycticeinops. It is named for the collector of the original specimen, Wilhelm von Schlieffen-Schlieffiennburg.
Van Gelder's bat or Van Gelder's big-eared bat is a species of vesper bat in the family Vespertilionidae. It is found in Belize, Costa Rica, Honduras, and Mexico. The species is monotypic within its genus. It is part of the tribe Antrozoini within the subfamily Vespertilioninae and is related to the pallid bat. The bat is found in forest habitat from sea level to elevations as high as 2300 m, although not usually above 1300 m, and is insectivorous and crepuscular. It apparently has a fragmented distribution, and is threatened by deforestation.
The Vespertilioninae are a subfamily of vesper bats from the family Vespertilionidae.
Ia is a genus of bat in the family Vespertilionidae. It belongs to the subfamily Vespertilioninae and has been placed in the tribe Vespertilionini. In the past, it has also been considered a synonym or subgenus of the genera Pipistrellus or Eptesicus, which used to contain many more species than they do now. Ia comprises a single living species, the great evening bat (I. io) of eastern and southeastern Asia, and one extinct fossil species, I. lanna, from the Miocene epoch in Thailand. Another living species, I. longimana, was recognized in the past, but it is no longer considered a valid species distinct from the great evening bat.
Nyctophilus is a genus of the vespertilionids or vesper bats. They are often termed Australian big-eared bats or long-eared bats, as the length of their ears often greatly exceeds that of the head. This genus occurs in the New Guinean-Australian region.
The Christmas Island pipistrelle was a species of vesper bat found only on Christmas Island, Australia. The species is now extinct, with the last individual bat seen in August 2009 with no further sightings despite intensive efforts to locate the species.
Antrozoini is a tribe of bats in the subfamily Vespertilioninae of the family Vespertilionidae. It contains the pallid bat, Van Gelder's bat, the genus Rhogeessa, and the fossil Anzanycteris. All species in this tribe are found in the Americas.
Necromantis is an extinct genus of bat that lived during the Eocene. Its fossils are found in the Quercy Phosphorites Formation of France and the Djebel Chambi in Tunisia. Specimens of Necromantis are notable for their large size and specialization towards a predatory lifestyle.
Aeorestes is a genus or subgenus of vesper bat commonly known as the hoary bats. As a genus, it includes species that were formerly included in the genus Lasiurus.
Dasypterus is a genus of or subgenus of vesper bat. As a genus, it includes species that were formerly in the genus Lasiurus. Collectively, members of Dasypterus are referred to as the yellow bats.
Lasiurini is a tribe of bats in the family Vespertilionidae. It contains three genera of bats found in the Americas. All three genera were previously considered one genus, Lasiurus, but have since been split from one another. However, the validity of this split is still debated.