This chapter considers the
fossil evidence for
diversification of the animal phyla into the major Classes -- fishes,
insects, mammals, etc, and also expands the Class of Mammals
to the next level. The full Creation Narrative
of course extends onwards to further levels of classification,
but we will stop at this level of detail
(see Figure 1)02
It should be remarked at the start that an attempt to understand the
role of evolution in this Narrative is doomed to frustration, at least
at present, because of the rather primitive level of understanding of
the basic mechanisms of how evolution really works its changes. So the
discussion is fated to be a bit incomplete. Ideally, one would like to
be able to describe just how (even in general terms) an "innovation" in
an animal class, order, etc. gets passed on to its descendents, but, in
fact, that critical piece of information is just not known. Or to put
it another way, one way that it isn't
done has been amply demonstrated in the Cult of Lysenkoism
which distorted science in the Soviet Union for half a century.
To take a more positive view, it is evident that the general plan of
the Creation Narrative is: each animal class fulfills a need
of the project of life and to
maintain a balance in nature. No plant or animal can multiply
unchecked, and no waste product can go unused. By necessity all
biological life must feed on other biological life or on life's waste
products. The earliest plants and animals fed on bacteria and
single-celled protists -- primarily algae. Thus one finds the worms,
trilobites and other animals that feed on this simple matter. Very
soon, animals arise that feed on other animals as well, and the early
animals develop armor and other defenses against hostile attack. As
animals increase in size and defenses, new animals appear with jaws and
teeth that can handle that increased challenge. This is the general
plan for advancement. In parallel, gradual changes in how animals
procreate and care for their offspring also develop, moving from
offspring that largely fend for themselves, to the development of
animals that parent their offspring in various ways, and finally to
mammals which both gestate and nourish their offspring.
The fossil record provides a revealing narrative of how these
developments of the Creation Narrative occurred in time. The remainder
of this chapter describes how the more prominent animal classes appear
in the fossil record. See Fossil
Illustrations of the
Plant and Animal Classes
for many illustrations contained in 19th
(A-3). The Sponges. Sponges
appear as early as the lower Cambrian (Figure 2). The Classes are based
on the type of skeleton: Hexactinellida (glass sponges = silica
spicules), Calcarea (calcium carbonate bodies and spicules),
Demospongea (silicate spicules or spongin fibers; sometimes massive
external CaCO3 skeletons) [Wiki]. The
siliceous sponges use silicatein enzymes03
to form the slicon spicules and other characteistic silica threads. The
silicatein enzyme has 330 amino acids and is produced by a 2,280
bp gene including
6 short introns. It appears to become active in the presence of iron
and silicon ions.
The order of appearance in the fossil record is: Hexactinellida first,
then Demospongea and finally Calcarea. All appear in the early Cambrian.
Hexactinellida. This is possibly the oldest sponge
"probable" examples found in
the Ediacaran Formation in
Figure 2 is an example from the
Ordovician. The longitudinal threads are composed of silica.
Archaeoscyphia Class Hexactinellida
A mid-Cambrian fossil is shown in Figure 3. Note the characteristic
silica threads (silicious spicules) along the
the only sponges with Calcium Carbonate spicules. The fossil record
begins in the lower Cambrian [UCMP Berkeley], but the record of
unambiguously identified Calcarea is relatively poor. Some confusion
can exist between fossil Calcarea and fossil Corals.
(Cnidarians). The Cnidarians are named
for their stingers (cnidoblasts are cells which contain the nematocyst
stingers), which are characteristic of the
phylum and come in many forms, sometimes exquisite engineering marvels.
There are five classes: Anthozoa (corals & sea anemones), Cubozoa
(sea wasps), Hydrozoa (hydras), Scyphozoa (true jellyfish), and
Staurozoa (stalked jellyfish). Many of the species have elaborate life
cycles, which makes them a favorite subject in zoology. The cnidoblasts
are marvels of engineering and use a variety of ingenious mechanisms to
activate the stingers --
see The Engineering
Anthozoa (corals & sea anemones). The
fossil record for corals goes back to pre-Cambrian times. Because they
form reefs, they are easily preserved, unlike the other classes of
Class Hydrozoa (hydras) The
oldest jellyfish with preserved softbody parts was discovered in Utah
2007 (Figure 5). It is dated to 507 Ma. Other fossils in this same
formation show nematocyst cells. The report of this fossil also found
fossils attributed to Classes Cubozoa and Scyphozoa at this same site,
suggesting that the Coelenterata classes were already in place by the
end of the Cambrian Age.
Class Cubozoa (sea wasps)
Class Scyphozoa (true jellyfish) -- Also
found in the Marjum Formation (See Figure 5).
Class Staurozoa (stalked
jellyfish - Stauromedusas)
Two phyla plus the extinct phylum of trilobites (here considered part
of the Chelcerata) form the super-group
of Arthropods. The (present-day) divisions are shown in Figure 6. By
far the Insecta class holds the greatest number of species.
Margulis divides the Arthropods into A-20 (Chelicerata)
and A-21 (Mandibulata). Trilobites would be related to A-20.
Chelicerata (A-20) (Cheli
= Claw). There are three classes of
Chelicerates: Meristomata, Pycnogonida, Arachnida plus the palaeozoic
class of trilobites.
Trilobites are the iconic fossils. They suddenly appear fully
formed in the early Cambrian (540-490 Ma) and continue until they
become extinct at the end of the Permian (250 Ma). Over this span of
300 My, many changes occur, particularly in the eyes, which evolve from
holochroal to schizochroal,
so that most (all?) of the trilobites have the advanced schizochroal
eyes in the end -- incorporated in the trilobite order Phacopida (genus
Figure 7 shows sketches of several of the early trilobites, shown in
relative size, which ranged from 1 to 25 or more cm.
The trilobites have primitive mouths with no chewing parts; on the
other hand they have a through gut, and other internal organs that
might be considered somewhat "advanced." It appears that they are
bottom-foragers who feed primarily on microscopic and small food
Class Merostomata (horseshoe
larvae of the horseshoe crabs pass through a "trilobite" stage in which
they resemble trilobites. The shell is tough but flexible, horn-like
chitin, unlike true crabs which have a brittle calcium (???) shell.
Dana, Geology (1896), p.473 & 476
Class Trilobita (Extinct)
(All to same scale)
Class Pycnogonida (sea spiders). The
sea spiders have almost no fossil record. They have so many unusual
features that some do not even consider them to be chelicerates.
They have a simple heart but no gills. The gut
extends through the long legs with an anal opening in the tail, which
appears to serve no particular function. It is not known whether the
sea spiders are an example of reductive evolution (having lost many
standard body parts) or are exceedingly primitive (an early branch of
the phylum). All other chelicerates have a full development pattern
with the hatched larva very similar to the adult. In contrast, the sea
spider larvae have only two pairs of legs and otherwise look quite
different from the adults. A small silurian fossil was reconstructed by
building up successive slices of the fossil embedded in rock, using
computer tomography. The result closely resembles modern species07.
Class Arachnida (Spiders, scorpions). A
Sea Scorpion from the Silurian Age (Figure 10) was reported in 2011 to
include actual molecules of chitin, advancing the earliest date of a
preserved complex biomolecule by almost 400 My08.
The Sea Scorpion belongs is an extinct order of
Arachnids found as early as Ordovician Age (some claim that there are
Cambrian examples). These include the largest arthropods that ever
lived. An 18 inch fossil claw from the lower Devonian (390 Ma), found
in 2007, would equate to a sea scorpion over 8 feet in length -- larger
than a human09.
Carboniferous (ca. 300 Ma)
A recent discovery of a small spider fossil in Inner Mongolia, China is
shown in Figure 11. This fossil is from the Jurassic (165 Ma). The
spider is preserved in amazing detail (see the leg detail).
Spider fossil, Family Plectreuridae
body length 3 mm.
Jurassic (165 Ma), Inner Mongolia, China
Note: Insert is magnified view of
a leg showing high detail.
(A-21) (Chewing arthropods). Chitin exoskeletons.
Insecta (Hexapoda), Crustacea, Myriapoda
(Hexapoda). The insect body plan has three
segments (head, thorax and abdomen), 3 pairs of legs and 1 pair of
antennas. The abdomen itself has eleven segments. The oldest fossil
insect was found in the Rhynie
Chert, in the early Devonian period (407-396 Ma). Other "firsts"
are: First flying insect -- fossil
dragonfly -- in the lower Carboniferous, 380 Ma; oldest fossil bee
in the Cretaceous, 100 Ma. Wikipedia
notes: "What seems most fascinating is that
insects diversified in a relatively brief 100 million years (give or
take) into the modern forms that exist with minor change in modern
times. ...There have been four super radiations of insects:
~300 million years ago), flies (evolved ~250 million years ago), moths
and wasps (evolved ~150 million years ago)."
One of the most remarkable inventions of the flying insects is resilin, an elastic
protein with a length of 620 amino acids. It is the most efficient
elastic protein known -- only 3% of
the stored energy is wasted in heat -- far better than rubber or any
other known elastic material. In addition it is remarkably durable, and
does not lose its elasticity with stretching or repeated use. It is
estimated that the resilin in a fly can be stretched 500 million times
over its lifetime without damage. Resilin is not produced by the adult
insects -- it is a carryover from the larval stage10.
Fossil Dragonfly. Fully-winged
suddenly in the Carboniferous (380 Ma). These fossils are the first
representatives of winged flight. Dragonflies (and mayflies) have fixed
wings -- they do not fold -- and they fly with a "rowing" muscle system
at the root of the wing. Most other insects have specialized muscles in
the wing which aid them in folding12. A
is the very large dragonfly-like insects with gossamer wings (Figure
cp. Figure 6 (L)). These are the largest insects that ever
The remarkable mechanics of insect flight. 11
18_2_91-97.pdf: Jerry Bergman, Insect
Evolution: a major problem for Darwinism. (Creation.com -- young
earth) TJ Technical Journal, 18 (2) 2004
"The insect wing is a complex, well-designed structure43 and the
insect’s ability to fly is a mystery that is only now being
unravelled.44 Made out of an extremely light, but amazingly strong,
tough material called cutin, wings are reinforced by a complex set of
various veins that provide structural support where needed, yet resist
bending and twisting to supply the needed strength.45,46 The 30-odd
wing muscles housed in the thorax are the most powerful muscles known
per square millimetre of cross-sectional area. Although 200 times per
second is typical in some insects, they can beat as fast as 1,000 times
per second.47 ... The origin of the insect wing and insect flight is
‘one of the most
controversial topics in paleoentomology’ ... Because bird
wing bones are homologous to animal limbs, it was long assumed that
evolved from limbs.50 Insect wings, though, are not modified legs, but
structures additional to the legs.51." [insect wings are readily
fossilized, so abundant (altho generally pieces, not whole] ... among
the hundreds of thousands of recognized insect species, nearly all can
be placed in one oranother of the approximately thirty
well-characterizedorders. ... Another problem is that insect wings do
not function independently, but must articulate appropriately with the
body, and must also function as a unit, which requires coordination by
a nervous system of great complexity. The energy needed for flight is
also enormous—as much as 100 times that needed for resting. ... the
folding wing is, in the words of a University of Chicago
neuroethologist, ‘the most morphologically complex joint in the animal
kingdom’.59 A variety of folding systems exists, including longitudinal
and transverse, all requiring unique muscle and nerve designs. 60 The
fossil record shows that folding wings have always existed in
insects—from the earliest forms found until those of today."
Carbonaceous meganeurid dragonfly
reconstructed (falsified) fossil
body length 1 ft. wingspan 2.5 ft.
Inset shows actual fossil -- most fossils are fragmentary.
Fossil Cockroach. The oldest fossil cockroaches are found
in the Mississippian (lower Carboniferous) age, about 350 Ma.
Figure 13 shows the largest and oldest complete fossil cockroach from a
coal mine dated in the late Pennsylvanian (upper Carboniferous), about
300 Ma, discovered in Eastern Ohio in 2001. The earliest fragments are
generally wing parts, which are made of chitin which preserves well and
is not easily digested.
Fossil Butterfly. The earliest fossil butterfly is from the
Eocene, about 40 My. The fossil pictured in Figure 14 is from the
Florissant Fossil Beds in Colorado and was discovered in 1887 by
Earliest Butterfly, Class Insecta
Eocene (39 Ma) (wingspan 1.0 in.)
Florissant Fossil Beds (CO)
Fossil Wasp, Class Insecta
Eocene (39 Ma) (scale = 1 cm.)
Florissant Fossil Beds (CO)
Class Crustacea (crabs, shrimp,
lobsters). Crustacea have 3 segments with 2 pairs of
antenna from head; a hard (calcium
carbonate strengthening of cutin) molting exoskeleton; each segment may
have appendages -- antennae, legs. etc.; and an open circulatory
Principle subclasses are: Brachiopoda (brine shrimp, water fleas),
Ostracoda, Copepoda, Cirripedia (barnacles), Malacostraca (lobsters,
crayfish, crabs, krill).
Fossil shrimp are known from the Jurassic Era (Figure 16).
The oldest fossil krill and true crabs also date from the Jurassic.
Lobster fossils date from the Cretaceous, some 50 My later (Lower
Cretaceous, 110 Ma)13.
Barnacles are mostly indirectly
evidenced in the destruction that they cause. There is evidence that
seems to be barnacle damage as early as the Devonian age. The oldest
"widely accepted" barnacle is from Silurian age, although some
disputed fossils have been identified as early as the Cambrian14
Priscansermarinus barnetti from the Burgess Shale, is a proposed
of gooseneck barnacles. The fossils from the Cambrian and Silurian are
"naked" and (in my view) somewhat arguable as to identity.
millipedes) Figure 17 is a millipede from the
mid-Pennsylvanian, ca. 305 Ma.
Millipede Pleurojulus Sp
mid-Pennsylvanian (305 Ma)
bar = 1 cm.
Mazon Creek, Ill. Carbondale formation
(Segmented worms). Three Classes: Polychaeta (= many
bristles) (Bristleworms), Oligochaeta (= few
earthworms), Hirudinea (leaches). "Because
the annelids have soft bodies, fossilization is exceedingly rare" -
Polychaeta (Bristleworms). "Definite
polychaetes appeared in the Cambrian."
Mississippian (350 Ma)
Bear Gulch, Montana
Figure 19 shows annelid worm tracks from the Silurian. Figure 19b is an
illustration published in 1844, and appears to be a sketch of the
actual fossil from the National Museum of Wales (Figure 19a).
Annelid Worm Tracks
Silurian (ca. 425 Ma)
Annelid Worm Tracks
Silurian (ca. 425 Ma)
Mantell, Medals of Creation (1844) p.
Oligochaeta (incl. earthworms).
"The earliest good evidence for oligochaetes occurs in the
Tertiary period, which began 65 million years ago."
Hirudinea (leaches). The
"Oldest Known Leech" is from the Pennsylvanian formation of Mazon Creek.
Mollusca (A-26). Three major classes:
Bivalvia (Bi-valves --
valves are on the left/right sides hinged at top) no defined heads; Gastropoda
(stomach-feet); and Cephalopoda (head-feet).
populous classes are: Monoplacophora, Polyplacophora, Rostroconchia,
Scaphopoda, and Aplacophora. Body plan includes a head-foot with
sensory and motor organs, viscera with a complete thru-gut digestive
system, a mantle which generally secretes a hard, calcium-based shell,
and a radula (toothed tongue -- not present in bivalves).
Molluscs are a favorite of geologists because they appear throughout
the geological column, and provide many characteristic marker fossils
that can be used to identify the various strata. There is a general
progression of complexity among the three classes, with the Bivalves
having the least complex systems to the Cephalapods having the most
complex -- well-developed nervous and sensory systems. The octopus
brain and eye are among the most advanced in the entire animal kingdom,
with the octopus eye quite similar to the human eye. At one time this
was considered to be an example of convergent evolution (the
development of analogous structures), but with the recent understanding
of evolutionary development (evo-devo) it is now known that the
development of eyes and appendages, as well as other features, are
directed by highly conserved hox genes.
Mollusc fossils are found in the Ediacaran Era, predating the Cambrian
(Bi-valves) no defined heads.
Class Gastropoda (stomach-feet)
Class Bivalvia -- Aviculopecten
Lower Carboniferous (350 Ma)
Logan Formation (Wooster OH)
Class Gastropoda -- Pleurotomaria
Silurian -- Wenlock Limestone
Cephalopoda (head-feet) nautilis, Ammonite (extinct), octopus,
squid. Some Cephalopods have well-developed brains and sensory
systems. They are "the most evolutionarily advanced animals to be found
The nautilis chambers (Figure 23) has been offered as an example
from nature of the Fibonacci series, however that appears to be in
sometimes serve as index fossils. The earliest
Ammonites appeared in the Devonian (400-360 Ma) and they became extinct
at the KT boundary (65.5 Ma).
Nautilis showing Chambers
Upper Jurassic (ca. 145 Ma)
Bryozoa (A-29). Three
major classes: Stenolaemata (Cyclostomata) = calcified colonies of
individual bryozoan zooids; Gymnolaemata = uncalcified; and the
Cheilostomata. Bryozoans are generally colonial zooids less than 1mm
long, have a U-shaped gut with the anus just behind the mouth;
tongue-like probe with called the lophopore, supplied with cilia to
create currents to bring fine particles to the mouth. The oldest
Bryozoan fossils come from the Ordovician.
Class Stenolaemata (Cyclostomata). Figure
24 shows fossilized colonies of this class from the Ordivician.
Bryozoan Colony Fragments
Class Gymnolaemata. Since this class is "naked" the
fossil record can be presumed to be sparse.
Class Cheilostomata. These
Bryozoa first appear in the late Jurassic [Wiki].
Brachiopoda (A-30) =
Lampshells. Characteristics: 2 unequal shells, each bilaterally
symmetric on the upper/lower surfaces in contrast to bivalve molluscs
which have a left/right arrangement [Wiki]. They
may be hinged at the top. There are two major types: articuate
and inarticulate. Most live attached to a surface and so are not
Upper Jurassic (140 Ma)
Inset: Linulite (convex
side) from the Eocene.
Classes (extant) [Wiki]:
Craniata (formerly Craniforma), Lingulata, Paterinata
(?), Rhynchonellata. Extinct classes: [ref:
see table at Fossilmuseum.net]
Sub-phylum Rhychonelliforma: Chileata, Obolellata, Kutorginata,
Strophomenata. The Lingulata have Calcium-phosphate
shells, and the others have calcite (CaCO3)
Lingulata. Calcium-phosphate/chitin shell. The Extinct genus Lingulella
(Lingulids) (Figure 26) was perhaps the most abundant fossil from
the Lower Cambrian to Silurian (?).
Craniata (= Craniforma). The Craniida ?? HOW TO IDENTIFY FROM
Rhynchonellata (former Articulata). The
Dana, Geology (1896), p.
548 & 560
Lower: Pentamerus, two species
Paterinata. The ?????
Other extinct classes can be found
in the fossil record.
Echinodermata (A-34) = "Spiny skin".
5-fold radial symmetry + water vascular system. Classes: Asteroidea
(sea stars, starfish, sea daisies), Ophiuroidea (brittle stars, basket
stars), Echinoidea (sea urchins, sand dollars), Crinoidea (Sea
lilies & feather stars), and Holothuroidea (sea cucumbers,
starfish, sea daisies).
Dana, Geology (1896), p.
(brittle stars, basket stars).
Silurian Brittle Star
(sea urchins, sand
of Creation (1844) p.
(Sea lilies &
feather stars). The Oldest Crinoids date to the Ordovician [Wiki]. "In
2006, geologists isolated complex organic molecules from
350-million-year-old fossils of crinoids—the oldest such molecules yet
found. Christina O'Malley, a doctoral student in earth sciences at The
Ohio State University, found orange and yellow organic molecules inside
the fossilized remains of several species of crinoids dating back to
the Mississippian period."
Buckland, Geology (1837), pl. 47
Carboniferous Stone Lilies
of Geology (1896), p.
holothurians). The fossil record of these worm-like animals is sparse
[UCMP] because they are soft-bodied. The earliest indications are
spicules rather than bodies. See the Tree of Life page
examples of fossil holothuroid ossicles.
Subphylum Verebrata. Most Chordates are
vertebrates. The term "vetebrae" means "to turn" [Mantell, p.
588] and all vertebrates enclose the main nerve bundle in a bony
column consisting of vertebrae which are connected by flexible
joints that can bend and twist.
Fishes during the late Silurian and Devonian give the clearest early
evidence of vertebrates. They constitute the first three classes:
Agnatha (jawless fish -- the lampreys and hagfish); Chondrichthyes or
Selachians (Cartilagenous jawed fish -- sharks and rays); and the
Osteichthyes or bony fish. All of these classes thrived in the Devonian
age (the "age of fishes") and their descendents thrive today. The
Coelacanth perhaps holds the record for longevity of a vertebrate
order. The first fossil on record is a jaw dated to 360 Ma. It is from
the class of bony fish (Osteichthyes) with the
characteeristic homocercal (symmetrical) tail.
Extinct (sub-) Class
Placoderma. This extinct class is sometimes considered a
subclass of the Selachians because it has a cartilagenous skeleton.
The (primarily British Isles) Old Red Sandstone formation spans from
the late Silurian, through the Devonian and into the early
Carboniferous Ages. The formation was at first thought to be remarkably
free of fossils, which were abundant both below (Silurian) and above
(Carboniferous). The early geologist Hugh Miller discovered many
remarkable fish fossils in
this formation near to his home in Cromarty, Scotland, in the late
1820s. He described his work,
written in his inimitable style in the book, Old Red Sandstone, originally
published in 1842. The fish fossils from his book are from the extinct
class of placoderms -- cartilagenous fish with heavy armor (Figure
33b). The geologist Hugh Miller
the Pterichthys (= "winged fish") in the Old Red Sandstone near to his
home in Cromarty, Scotland16. It is
notable for the "arms" that act as fins but are relatively inflexible.
Some geologists consider them to be spines which normally lay along the
side but extend out when the fish is alarmed.
Selachians -- Placoderms
Upper Devonian (365 Ma)
Selachians -- Placoderms
Pterichthys oblongus Ag.
Upper Devonian (365 Ma)
(Jawless Fish, no scales -- lampreys and hagfish).
Ordovician Cyclostomes Ostracoderms ("shell-skinned")
are any of several groups of extinct, primitive, jawless fishes that
were covered in an armor of bony plates. Ordovician, Silurian,
and Devonian agnathans were armored with heavy bony-spiky plates. The
first armored agnathans—the Ostracoderms, precursors to the bony fish
Class Chondrichthyes (= Selachians) (Cartilagenous
jawed Fish, no Phosphate of Lime -- sharks and rays) Phosphate of lime
An early fossil is shown in Figure 34. Note the typical heterocercal
tail, which today is seen in sharks. Many of the earlier examples of
these fish have teeth that are not embedded in the jaws.
Class Chondrichthyes (Selachian)
Class Osteichthyes (
Phosphate of Lime) Probably the most
famous "living fossil" from this class is the Coelacanth (figure 35).
oldest known fossil of a Coelacanth is a jaw found in Victoria,
Australia and dated to the early Devonian, around 407-409 Ma17
Upper Jurassic Coelacanth
Class Amphibia (land/water
-- gills and lungs; larval stage -- frogs, toads, salamanders). All of
the non-fish classes of vertebrates have radially symmetric bodies with
four limbs. Amphibians were the first vertebrate animals to move to
land. The natural habitat of an amphibian is the shorelines of lakes,
rivers and the oceans. All amphibians have a stage of life in which
they live in water, and in fact they require a water medium for
fertilization, which takes place outside of the body. One reason for
this is that amphibia do not have an amniotic egg, as do the other
Amphibians first appear in the fossil record in the mid-Devonian Age.
In many instances the earliest indications of their existence is in
tracks and footprints that they made in mudflats. In 2007, the New
Mexico Museum of Natural History reported a full-body
impression of three salamanders (one of the three shown in Figure 36b)
from the early Mississippian Age, about 330 Ma. This fossil impression
had been collected many years earlier but not identified prior to this
report. The earliest known fossil is from the Late Devonian of
Scotland, about 38 My earlier (368 Ma)18.
Coal formation, Osage, KS
Amphibian body imprint, length abt. 8"
Mississippian (330 Ma)
Mauch Chunk, PA
(lungs; amniotic egg, internal fertilization. Lizards,
dinosaurs). The development of the amniotic egg, or more
generally the amniotic sac, is one of the most important and remarkable
inventions that permits animals to live and reproduce on dry land.
Lizards are reptiles and
salamanders are amphibians. Reptiles have a rough dry skin, whereas
salamanders have a soft moist skin. The first reptiles appear in the
mid-Carboniferous era, about 340 Ma.
The crowning achievement of the reptiles is the invention of the
Mesosaurs are the first aquatic reptiles -- perhaps the earliest
amniote. Figure 37 is a mesosaur fossil embryo from the Lower Permian
(280 Ma), the oldest fossil example of the birth (or perhaps
miscarriage) of an amniote. "Prior
to the development of the amniotic egg,
amphibians were "chained" to the ocean or some other large body of
water, because they had to lay their eggs in water. If the eggs were
removed from water and placed on land, they would simply dry out,
obviously killing the egg." [Wiki] Thus reptiles were the first that
could migrate to dry land for their entire life cycle.
Lower Permian (280 Ma) - Uruguay
length of embryo about 1 cm.
(wings; warm-blooded, feathers) Birds and mammals are warm-blooded. All
other vertebrates are cold-blooded.
Archaeopteryx. First feathers -- flight feathers.
Dinosaur or bird? See Wiki. Late Jurassic, ca. 150 Ma. p788 Dana
birds have light-weight bones.
(mammary glands). The mammals are the vertebrates that are most
familiar to us. The earliest to appear are the Marsupials (most of the
development of the fetus occurs outside of the womb) followed by the
Placentals (most of the development occurs in the womb). Mammals have
dominated animal life since the C-T extinction event (65 Ma) which
wiped out the dinosaurs and many other species.
Late Jurassic (ca. 150 Ma)
Solnhofen Quarry, Germany (1861)
Note: The original fossil
Mammals are characterized by being warm-blooded, and possessing hair,
three middle ear bones for balance and hearing19],
and mammary glands. [Ref: Wikipedia].
Red blood cells (lacking a nucleus) and a 4-chambered heart are also
Mammals are divided into the following infraclasses, each of which
involves major differences.
Mammals that lay eggs
Mammals that give birth to undeveloped young (Kangaroos, opossum)
InfraClass Placentalia (Eutheria)
Placental mammals that develop the young in the womb before giving
birth. The oldest fossil of a placental animal is a shrew-like animal
from the Jurassic Age, figure ??, announced in 2011.
Various "firsts" among the placental animals indicate
how the modern mammals originated. Most of these fossils consist of
individual bones and disarticulated fragments rather than complete
specimens. See also Footnote 19 below.
Oldest Placental Mammal
Jurassic (160 Ma)
Elephants and Mastodons. Mastodons and Elephants have
different types of molars. The oldest fossil Mastodon (family
Mammutidae) is from the Congo, from the Eocene (40 Ma). The Mammoths are the oldest true
The ancestor of mammoths and elephants appeared in the late Miocene (7
• Oldest Whale. In 2011, the
oldest whale fossil (bone) was reported. It was a jawbone from
Australia, from the early Eocene, (49 Ma). This discovery poses some
serious problems for the speed of
evolution, because of the many anatomical changes needed to convert a
land mammal into a whale. "There just isn't time."20
Bat. The Oldest bat fossil, a perfectly preserved specimen, is
from the Eocene (48 Ma) (Figure ??).