part_of gaster presclerite SIBO:0000142 Presclerite- A distinctly differentiated anterior section of an abdominal sclerite, separated from the remainder of the sclerite by a ridge, constriction, or both. In the ant abdomen it is usual for the posterior portion of each sclerite to overlap the anterior portion of the following segment. The overlapped area usually lacks sculpture and pilosity, but the absence of these features alone does not constitute a presclerite. Presclerite derived from tergites are termed pretergites, those from sternites, presternites. The remainder of each sclerite, posterior to these developments, is the postsclerite and may be termed posttergite and poststernite, respectively. The presclerites of abdominal segment 3 form a very specialized articulateio with the posterior end of abdominal segment 2, termed the helicum. (Bolton, B. (1994). Identificstion guide to the ant genera of the world. Cambridge, Mass., Harvard University PRess. pp.1-222). sibo