Two new species of giant pill-millipedes, Zephronia viridisoma Rosenmejer & Wesener sp. nov. and Sphaerobelum aesculus Rosenmejer & Wesener sp. nov., are described based on museum samples from southern Thailand. Zephronia viridisoma sp. nov. comes from Khao Lak, while the type locality of S. aesculus sp. nov. is on Phuket Island. Both species are described integratively, combining light microscopy, scanning electron microscopy, multi-layer photography, micro-CT scans and genetic barcoding. Genetic barcoding was successfully conducted for holotypes of both new species, which could be added to a dataset of all published sequences of the family Zephroniidae, including all described species from Thailand, Laos and Cambodia up to 2020. Genetic barcoding of the COI gene revealed another female of S. aesculus sp. nov., 160 km east of the type locality. Both new species are genetically distant from all other Zephroniidae from Thailand and surrounding countries, showing uncorrected p-distances of 16.8–23.1%. A virtual cybertype of a paratype of Z. viridisoma sp. nov. was created and made publically accessible.

We report fluid feeding with a sucking pump in the arthropod class Diplopoda, using a combination of synchrotron tomography, histology, electron microscopy, and three-dimensional reconstructions. Within the head of nine species of the enigmatic Colobognatha, we found a pumping chamber, which acts as positive displacement pump and is notably similar to that of insects, showing even fine structural convergences. The sucking pump of these millipedes works together with protractible mouthparts and externally secreted saliva for the acquisition of liquid food. Fluid feeding is one of the great evolutionary innovations of terrestrial arthropods, and our study suggests that it evolved with similar biomechanical solutions convergent across all major arthropod taxa. While fluid-feeding insects are megadiverse today, it remains unclear why other lineages, such as Colobognatha, are comparably species poor.

An inventory of the Myriapoda (Diplopoda, Chilopoda, Symphyla) from Cretaceous Burmese amber, Myanmar, is presented, including the oldest and/or first fossil record for numerous orders. For millipedes (Diplopoda) 527 records, including 460 new specimens determined by us, belonging to 13 of 16 recent orders are listed: Polyxenida, Glomeri­desmida, Glomerida, Siphonophorida, Polyzoniida, Platydesmida, Siphoniulida, Chordeumatida, Polydesmida, Stemmiulida, Callipodida, Spirostreptida and Spirobolida. For centipedes, 33 records for 4 of the 5 recent orders are listed: Scutigero­morpha, Lithobiomorpha, Scolopendromorpha and Geophilomorpha. For Symphyla, three records for both families, Scutigerellidae and Scolopendrellidae, are listed. The majority of Diplopoda records (30.5%) are Polydesmida. The record of the Polyzoniida includes first instar octopod juveniles. The checklist includes the first fossil representatives known of the Platydesmida, as well as the oldest known fossils of the Polyxenida, Glomeridesmida, Glomerida, Siphono­phorida, Polyzoniida, Siphoniulida, Spirostreptida, as well as both Symphyla families. Misidentifications by Zhang (2017) are corrected; while most Chilopoda in that list are correct, almost all Diplopoda are misidentified.

Solar-powered sea slugs are famed for their ability to survive starvation due to incorporated algal chloroplasts. It is well established that algal-derived carbon can be traced in numerous slug-derived compounds, showing that slugs utilize the photosynthates produced by incorporated plastids. Recently, a new hypothesis suggests that the photosynthates produced are not continuously made available to the slug. Instead, at least some of the plastid’s photosynthetic products are stored in the plastid itself and only later become available to the slug. The long-term plastid-retaining slug, Elysia timida and its sole food source, Acetabularia acetabulum were examined to determine whether or not starch, a combination of amylose and amylopectin and the main photosynthate produced by A. acetabulum, is produced by the stolen plastids and whether it accumulates within individual kleptoplasts, providing an energy larder, made available to the slug at a later time. Histological sections of Elysia timida throughout a starvation period were stained with Lugol’s Iodine solution, a well-known stain for starch granules in plants. We present here for the first time, an increase in amylose concentration, within the slug’s digestive gland cells during a starvation period, followed by a sharp decrease. Chemically blocking photosynthesis in these tissues resulted in no observable starch, indicating that the starch in untreated animals is a product of photosynthetic activity. This suggests that kleptoplasts function as both, a nutritive producer and storage device, holding onto the polysaccharides they produce for a certain time until they are finally available and used by the starving slug to withstand extended starvation periods.

The entire Mesozoic Era is rather poor in millipede (class Diplopoda) fossils, with less than a dozen species being taxonomically described. Here, we describe the first fossil millipede of the order Callipodida,Burmanopetaluminexpectatumgen. nov. et sp. nov., found in early Cenomanian amber of Burma, 98.79±0.62 Mya. The species possesses a number of morphological traits that exclude it from all extant suborders, and Burmanopetalidea suborder nov. and Burmanopetalidae fam. nov. are here erected to accommodate it. The new suborder can be recognized by the following unique characters: pleurotergal setae absent; telson with a specific spatulate shape twice the size of the penultimate body ring; hypoproct devoid of setae; and eyes composed of five well-separated ommatidia. While the callipodidan habitus seems to have remained generally unchanged for at least 99 million years, pleurotergal and hypoproctal setation, as well as the complexity of eyes in ground-dwelling forms may have evolved recently in the order. AsB.inexpectatumgen. nov. et sp. nov.is the first true callipodidan in the fossil record, the minimum age of Callipodida is thus at least 99 Mya.