Karlingocelis cannoni sp. nov. ZooBank: urn:lsid:zoobank.org:act: BFA3F570-311C-4607-ADD7-ED6B9B741853 (Fig. 2 I–O) Diagnosis. Species of Karlingocelis with a stylet about 70 µm long, 5–10 µm wide and with a proximal opening 20 µm across; three to four pairs of sharp hooks about 25 µm long, provided with conspicuous apophyses. Karyology: n=5; FN=7. Occurrence. Heron Island, Queensland, Australia, in front of the Heliport, about 1.5 m deep in very silty coarse sand and gravel (Lat. –23.441724, Long. 151.910765 (October 1993) (type locality). Material studied. Observations on live animals, two whole mounts, one of which designated holotype (QM G238525), the other paratype (CZM 858). Etymology. Species dedicated to Dr. Lester Cannon, former curator of the worm collection of the Queensland Museum, who greatly promoted research on Australian Platyhelminthes. Description. Animals similar in size and morphology to the previous species. The copulatory organ consists of a straight stylet, around 70 µm long, 20 µm in diameter at its proximal side, narrowing to 10 µm and ending at 5–7 µm at the distal opening. There are six to eight hooks connected to relatively thick muscles, whose surrounding matrix is sclerotised in various degrees, presumably related to the maturity stage of the specimens observed. In one specimen, the nuclei of these muscles were clearly visible (Fig. 2 O). The hooks are very slender, 25 µm long and less than 3 µm thick with a sharp recurve distal tip and a thin, prominent apophysis. The number of hooks varies from six (Fig. 2 M) to seven (Figs. 2 L, O) and eight (Figs. 2 J, K, N): this latter seems to be the most common number. Karyotype. With five pairs of evenly-sized chromosomes; two pairs are meta- to submetacentric, and three pairs are distinctly heterobrachial (Fig. 2 I).

Published as part of Schockaert, Ernest R. & Curini-Galletti, Marco, 2025, New species of Archimonocelididae Meixner, 1938 (Platyhelminthes, Proseriata) from the Pacific Ocean, with the proposal of three new genera, pp. 527-542 in Zootaxa 5722 (4) on pages 531-532, DOI: 10.11646/zootaxa.5722.4.4, http://zenodo.org/record/17892636