Archaebranchinecta

Diagnosis. Male. Cuticle with granulations throughout the whole body, mainly in the head, genital and abdominal segments, and gonopods. First antennae partially multi-articulated with incomplete rings. Second antennae basal antennomere with a basal and a more distal swollen bulge in its anterior surface, and three medial processes: pedunculate, digitiform, and small. Mouthparts as in the family. Rigid basal portion of each gonopod bearing a medial projection with a proximal process (wide, triangular or tongue-shaped, rounded at the tip, pointing mediodorsally) and a distal process (spiny, pointing medially); eversible portion of the gonopod very long, reaching the abdominal segment III or the beginning of IV. Wide V-shaped vas deferens along the genital region, which becomes a thin duct that loops before entering the partially everted or non-everted gonopod, or stretches in wholly everted gonopod. Thoracopods without sexual dimorphism. Abdominal segment II bearing a pair of ventrolateral hypertrophied denticulate sensory areas, also present but less developed in abdominal segments IV and VI. Female. Cuticle with granulations, mainly evident in the head, genital and abdominal segments, and brood pouch. First antennae as in male. Second antennae cheliform, with a conical strong medial projection. Mouthparts as in male. Thoracopods as in male. Abdominal segment II, IV and VI bearing similar ventrolateral denticulate areas as in male.