Level 1 — Absolute Beginner
The La Brea Tar Pits are a famous place in Los Angeles with many old animal bones.
Scientists found a new kind of toad in old bones from the tar pits.
This toad lived a very long time ago, during the Ice Age. It is now extinct.
The new toad's name is Spea labreae. A scientist named Dr. Alberto Cruz found it.
- fossil
- the remains of a very old plant or animal preserved in rock or tar
- extinct
- no longer existing; died out completely
- species
- a group of living things that share the same features
- toad
- a small animal with rough, bumpy skin that hops
- Ice Age
- a long period in the past when much of Earth was covered in ice
- scientist
- a person who studies the natural world
- collection
- a group of objects gathered and kept together, often in a museum
- discover
- to find something for the first time
Level 2 — Elementary
Scientists studying the famous La Brea Tar Pits in Los Angeles have discovered a brand new species of extinct toad, one they have named Spea labreae, a type of spadefoot toad that lived during the last Ice Age.
The discovery makes Spea labreae only the second extinct Ice Age amphibian species ever found anywhere in North America. The only other one is a tree frog that was found in Florida.
The find was made by Dr. Alberto Cruz, a postdoctoral researcher who was not originally searching for a new species. He was simply reviewing the tar pits' large but understudied collection of amphibian and reptile fossils when he noticed features that set this toad apart from every known spadefoot toad species.
The key piece of evidence was an incomplete bone called the sacro urostyle, which sits at the base of the spine where it connects to the hips. Dr. Cruz's study also found the first ever record of a Mexican burrowing toad living in ancient Los Angeles, a species whose closest living relatives today are found nearly 2,500 kilometers away in southern Mexico.
- spadefoot toad
- a type of toad with a spade shaped growth on its hind feet used for digging
- amphibian
- a cold blooded animal, like a frog or toad, that usually lives both on land and in water
- postdoctoral
- describing a researcher who has completed a doctoral degree and continues research training
- understudied
- not researched or examined as thoroughly as it should be
- evidence
- facts or objects that help prove something is true
- spine
- the row of connected bones running down the back of an animal
- relative
- a living thing that is related to another through shared ancestry
- burrowing
- digging into the ground to make a hole or tunnel
Level 3 — Intermediate
A new study of long overlooked fossils from the La Brea Tar Pits in Los Angeles has identified a previously unknown extinct species of spadefoot toad, Spea labreae, adding only the second confirmed extinct Ice Age amphibian species ever documented in North America, following an earlier discovery of a tree frog in Florida.
The discovery was made by Dr. Alberto Cruz, a postdoctoral fellow who was not initially searching for new species when he began reviewing the tar pits' extensive but historically understudied collections of amphibian and reptile fossils. While examining the material, he identified distinctive skeletal features that separated this specimen from every previously described spadefoot toad species.
The holotype specimen, the single physical example used to formally define the new species, consists of an incomplete sacro urostyle, the bone at the base of the spine where it connects to the hips. Despite its fragmentary nature, the bone preserved enough distinguishing anatomical detail for Dr. Cruz to confidently establish Spea labreae as a distinct species.
The same study also documented the first fossil record of a Mexican burrowing toad at the Tar Pits, a species that no longer inhabits the Los Angeles region; its nearest living populations today are found roughly 2,500 kilometers away in southern Mexico. Researchers say this finding offers a valuable window into how past climate shifts have already reshaped species distributions, a pattern with direct relevance to how present day climate change may continue to alter where species can survive.
- overlooked
- not given enough attention or consideration
- document
- to record something formally as evidence
- specimen
- an individual example of an organism used for scientific study
- holotype
- the single physical specimen used to formally define and name a new species
- fragmentary
- made up of small, incomplete, or broken pieces
- anatomical
- relating to the physical structure of an organism's body
- distribution
- the geographic pattern of where a species is found
- inhabit
- to live in or occupy a particular place
Level 4 — Advanced
A reexamination of long neglected fossil holdings at Los Angeles's La Brea Tar Pits has yielded the formal description of a previously unrecognized extinct species, the spadefoot toad Spea labreae, a discovery that constitutes only the second confirmed instance of an extinct Pleistocene amphibian documented anywhere in North America, following the earlier identification of a tree frog species from Florida.
The identification emerged not from targeted fieldwork but from an incidental review: Dr. Alberto Cruz, a postdoctoral fellow, was surveying the Tar Pits' voluminous yet historically understudied amphibian and reptile holdings when he recognized skeletal features inconsistent with any previously described member of the genus Spea, prompting a closer taxonomic investigation.
The formal designation rests on a single holotype specimen, an incomplete sacro urostyle, the fused skeletal element at the base of the vertebral column where it articulates with the pelvis. That the fragmentary bone retained sufficient diagnostic morphology to support a new species designation underscores both the rigor of the analysis and the scientific value still latent within decades old, seemingly exhausted museum collections.
Beyond the type description, the study yielded a second significant result: the first fossil evidence of the Mexican burrowing toad within the Tar Pits assemblage, a species whose extant range has since contracted dramatically, with the nearest living populations now confined to areas roughly 2,500 kilometers south, in Mexico. Researchers frame this range contraction as a tangible, fossil documented precedent for how climatic shifts, past and present, can restructure the geographic distribution of species, lending the discovery a relevance that extends well beyond Pleistocene taxonomy into contemporary conservation science.
- neglected
- not given proper care or attention over time
- Pleistocene
- the geological epoch commonly known as the Ice Age, spanning roughly 2.6 million to 11,700 years ago
- incidental
- happening as a minor or secondary result of something else, not the main intended outcome
- taxonomic
- relating to the scientific classification of organisms into named groups
- articulate
- (of a bone or joint) to connect or form a movable junction with another
- morphology
- the study or description of the form and structure of an organism
- latent
- existing but not yet developed, visible, or fully realized
- contraction
- a reduction in size, range, or extent
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