Paleobiology and paleoecology Palaeochiropteryx

fossil palaeochiropteryx tupaiodon in musee d histoire naturelle, brussels



fossil in vienna

messel pit (known in german grube messel) 1 of famous , richest fossil sites of world. site renowned quality of preservation in fossils found. preserved in fragile bituminous shale, retain exquisite details of soft parts of animals , plants. name suggests, pit dry depression 60 m (200 ft) deep; surface around 200 m (660 ft) above sea level. covers area approximately 1,000 m (3,300 ft) 700 m (2,300 ft).

48 million years ago, pit small deep lake, @ least 190 m (620 ft) deep. located around 10° south of current location in tropical , subtropical eocene europe. messel pit volcanic in origin, caldera created massive volcanic eruption. remained geologically , tectonically active during eocene, intermittently releasing puffs of poisonous volcanic gases. virtually stagnant lake, low oxygen levels enabled types of preservation found in fossils.

messel pit surrounded lush tropical jungle ecosystem teeming wildlife. among these several bat species, including palaeochiropteryx. fossils of palaeochiropteryx (particularly palaeochiropteryx tupaiodon) occur in great abundance in pit. account three-fourths of recovered bat fossils in area.

the fossils recovered of healthy adults full stomachs, making reasons why ended @ bottom of lake bit of mystery. may have been snagged or poisoned thick algal mats on surface of lake swooped down drink. or may have been knocked out midair poisonous fumes rising lake , subsequently drowned.

the small bodies of palaeochiropteryx coupled relatively broad wingspan indicate may have been low level flyers, modern bats same body structure. specialized in hunting close ground, beneath jungle canopy , among vegetation unlike other bats found in messel pit flew @ higher altitudes (an evidence of niche partitioning). had low wing loading , low aspect ratios, suggesting relatively slow flyers able maneuver midair – essential avoiding collisions numerous obstacles near forest floor. fact may have made them vulnerable poisonous gases of former messel lake, explaining abundance of fossils.

the shape of teeth , stomach contents of numerous extremely preserved fossils of messel pit indicate palaeochiropteryx insectivorous. p. tupaiodon fed exclusively on (presumably slow-moving) moths of primitive microlepidoptera family. p. spiegeli, on other hand, consumed caddisflies (trichoptera) in addition moths. members of insect families active @ night, giving strong indication palaeochiropteryx nocturnal, or @ best, active during twilight (crepuscular).

echolocation

from results of radiographic analysis, palaeochiropteryx (as archaeonycteris , icaronycteris) have enlarged cochleae relative size of skulls. still smaller of modern echolocating insectivorous bats (microchiroptera) larger of modern non-echolocating fruit-eating bats (megachiroptera). along known diets , habits, clear evidence palaeochiropteryx capable of echolocation modern microchiropterans.