Megalothorax rubidus

Differential diagnosis. Megalothorax rubidus is similar to the three new species and to M. granulosus from the reduced chaetotaxy of the basomedian field of labium. The presence of the secondary granulation on the head and thorax clearly sets it apart from the three new species group. It can be distinguished from M. granulosus by its fine granulation (coarse in M. granulosus). Furthermore, its external post-labial chaetotaxy is so far unique among Megalothorax species.

Comments. The specimen poor preservation prevents a complete chaetotaxic analysis, redescription from new material would be desirable. Due to the slide preservation, it was not possible to observe the whole extension of the secondary granulation but could confirm that it is at least partially present dorsally on the head, the thorax and the abdomen.

Material examined. A single slide labeled as “ Dominion Museum. N. Z. 536. Slide 3 / 1823, Deep red alive, Paratype. Gertrude Cirque, Homer in moss and lichen on forest floor. Coll. J. T. Salmon. 28 / 12 / 1944. Mnt KOH & P. V. A. Det. J. T. Salmon 1946 ”. New elements of description. Fine secondary granulation present dorsally on the head, thorax and abdomen. Labrum a 1 chaetae acuminate. Basomedian field of labium with 1 + 1 chaetae. Ventrally on head, with 1 + 1 external post-labial chaetae much larger than the 2 + 2 median post-labial chaetae.