A Miocene pyrgodesmid millipede (Polydesmida: Pyrgodesmidae) from Mexico

Area of Science:

• Paleontology
• Arthropodology
• Evolutionary Biology

Background:

• The millipede family Pyrgodesmidae is pantropical, with most species found in the New World.
• The genus Myrmecodesmus, belonging to Pyrgodesmidae, has a known distribution primarily in the Neotropics.
• Fossil records of millipedes provide crucial insights into their evolutionary history and past geographic distribution.

Purpose of the Study:

• To describe a new fossil species of pyrgodesmid millipede.
• To establish the first fossil record for the genus Myrmecodesmus.
• To expand the known geographic and temporal range of the genus Myrmecodesmus.

Main Methods:

• Description of a new species based on two amber inclusions (male and female).
• Analysis of morphological characteristics, including the collum, porosteles, ozopores, and leg projections.
• Stratigraphic and geographic context of the fossil material (Miocene strata, Chiapas, Mexico).

Main Results:

• A new fossil species, Myrmecodesmus antiquus sp. nov., is described from the Miocene of Mexico.
• The species exhibits distinct morphological features: 10 dorsal tubercles on the collum, absence of porosteles or ozopores, and a projection on the prefemur of legs 2-9.
• This discovery marks the first fossil evidence for the genus Myrmecodesmus.

Conclusions:

• Myrmecodesmus antiquus sp. nov. is the earliest known representative of its genus.
• The discovery extends the known range of the genus Myrmecodesmus to the Miocene tropics of Middle America.
• This fossil contributes to understanding the paleobiogeography of the New World millipede fauna.