ИСТИНА

The Acrothoracica together with the Thoracica and the Rhizocephala comprise the subclass Cirripedia. The acrothoracicans represent small, diecious barnacles that lead an endolitic way of life. The females burrow into calcareous substrata such as mollusk shells, corals, bryozoans, thoracican barnacles or limestone and calcareous chalk. The morphology of acrothoracicans indicates that they represent the most generalized group within Cirripedia. Traditional systematics of the group is based mainly on a few characters from females and contradicts with numerous new data on female, dwarf male and larval morphology obtained by me. I reviewed the systematics of the Acrothoracica and propose two new orders, viz., the Lithoglyptida order nov. and Cryptophialida order nov. The Lithoglyptida are characterized by females having a sac-like mantle without a neck area, a big, saddle-like labrum, developed mouth cirri, a thorax without long dorsal processes and a gizzard (gastric mill) being absent; the surface of the dwarf males have numerous cuticular projections and lacks mantle teeth; the cypris larvae have developed thoracopods, completely covered by the unperforated carapace, lattice organs with terminal pores, and a fourth antennular segment with setae grouped into a subterminal and a terminal set. In contrast, species of the Cryptophialida are characterized by females having a bottle-like mantle with an elongated neck area, elongated, a tongue-like labrum, rudimentary mouth cirri, a thorax with 1-2 whip-like, long dorsal processes, an intestine with a gizzard (gastric mill); the surface of the dwarf males is without numerous cuticular processes and often bears conspicuous mantle teeth; the cypris larvae have rudimentary thoracopods, a perforated carapace not covering the larval body completely, lattice organs without terminal pores and a fourth antennular segment with only terminal setae. I carried out a cladistic analysis for reconstruction of the phylogeny of the Acrothoracica (with Thoracica and Ibliformes as the out-groups), using characters of females, dwarf males and cypris larvae, including ultrastructural data. I developed a matrix of 65 morphological characters. These data were subjected to a parsimony analysis in search of the shortest trees. The Acrothoracica form a monophylum on supported by apomorphies such as chitinous opercular bars, separated terminal cirri and a boring apparatus from ctenoid scales. Two groups corresponding to the orders Lithoglyptida (with the families Lithoglyptidae and Trypetesidae) and Cryptophialida were distinguished. The reconstructed phylogeny reflects a new taxonomy for the Acrothoracica. Almost all characters of the Cryptophialida represent autapomorphies, whereas the majority of the characters found in the Lithoglyptida are plesiomorphies. However, several synapomorphies between the two families of the Lithoglyptida assures the monophyly of that order and distinguish them from the Cryptophialida. These are the orificial knob in females, the complication of dwarf male morphology (lateral “wings” of male body and long attachment stalk) and the terminal setae of the fourth antennular segment of the cypris larvae having a more complex morphology in comparison with those in the cryptophialids.