Terrestrial Isopods from Spanish Amber (Crustacea: Oniscidea): Insights into the Cretaceous Soil Biota Author Sánchez-García, Alba Author Peñalver, Enrique Author Delclòs, Xavier Author Engel, Michael S. text American Museum Novitates 2021 2021-08-06 2021 3974 1 32 https://bioone.org/journals/american-museum-novitates/volume-2021/issue-3974/3974.1/Terrestrial-Isopods-from-Spanish-Amber-Crustacea--Oniscidea--Insights/10.1206/3974.1.full journal article 10.1206/3974.1 0003-0082 5356138 49456979-A3B8-410F-BB0B-EBAD6B2E606B Heraclitus , new genus TYPE SPECIES : Heraclitus helenae , new species . DIAGNOSIS: Sex unknown. An oniscidean with the following combination of characters: Body size small (< 2 mm ), more or less oblong, with pleon much narrower than pereon; dorsal surface convex, with epimeral plates only moderately prominent, rough, covered with large semicircular scales and densely crowded prominent triangular-shaped scale setae. Antenna rather stout, with flagellum composed of at least three articles. Pereopods all alike, of moderate size, armed with elongate, thick, nearly straight spines arranged in a longitudinal row on sternal margin; dactylus with two claws, inner claw minute; dactylar setae unbranched, glabrous, long, and slender, distinctly expanded distally. Uropod moderately elongate; protopod long and stout, produced inside pleotelson, with endopod and exopod inserted at same level; exopod styliform, much longer than endopod; endopod conical, with a terminal tuft of setae. ETYMOLOGY: The genus group name honors the pre-Socratic philosopher Heraclitus of Ephesus (ca. 535–475 B.C.E.), early rationalist, empiricist, and founder of philosophical ontology. We have used the common Latinized form of his Greek name. The gender of the name is masculine.