part of has characteristic develops from prothoracic segment metatarsus prothoracic tarsal segment prothoracic metatarsus T1 tarsal segment 1 prothoracic tarsal segment 1 FBbt:00004669 UBERON:6004670 fly_anatomy.ontology First tarsal segment of the prothoracic leg. Proximally, it articulates with the tibia and distally with the second tarsal segment. Its surface is covered with eight longitudinal rows of bristles and with transverse rows of bristles (TR) in the anterior compartment, between proximo-distal rows 7 and 8. There is sexual dimorphism in the number of TRs (transverse row bristles, TR). In males, 2 TRs are replaced by the sex comb and one central bristle. FBbt:00004670 T1 Ts1 prothoracic basitarsus presumptive prothoracic metatarsus sexually dimorphic