Cephalopharynx cannoni, Hochberg, 2004

Hochberg, Rick, 2004, A new genus and subfamily of Typhloplanidae (Platyhelminthes, Rhabdocoela) from Australia with a cladistic analysis of subfamily relationships, Journal of Natural History 38 (8), pp. 925-937 : 928-933

publication ID	https://doi.org/ 10.1080/0022293021000058970
DOI	https://doi.org/10.5281/zenodo.4654048
persistent identifier	https://treatment.plazi.org/id/03B5991D-FF25-FF9E-A426-FBE6373FFB2D
treatment provided by	Carolina
scientific name	Cephalopharynx cannoni
status	sp. nov.

Treatment

Cephalopharynx cannoni View in CoL sp. nov.

( figures 2–7 View FIG View FIG View FIG View FIG View FIG View FIG )

Material examined

HOLOTYPE: Australia, Queensland, North Stradbroke Island, Amity Point , intertidal in medium sand (June 2002), whole-mount (polyvinyl lactophenol): G219290.

PARATYPES: same location as holotype, two adult whole-mounts (polyvinyl lactophenol): G219291–G219292; three immature wholemounts (polyvinyl lactophenol): G219293–G219295; two sectioned specimens stained with Mallory’s trichrome: G219296–G219297.

Other material. Fourteen specimens collected intertidally, studied alive and as whole-mounts (June 2002). One specimen collected subtidally in July 2002.

Etymology

The genus and subfamily are named after the anterior position of the pharynx (greek cephalo: head; greek pharynx: throat). Species epithet is dedicated to Dr Lester R. G. Cannon, former Senior Curator of Invertebrate Zoology at the Queensland Museum.

Description

Animals to 384 µ m long and 192 µ m wide with an oval body ( figure 2 View FIG ). A tail is never present. Body opaque with a glandular intestine. The entire epidermis is ciliated and may be partly syncytial. Epidermis height to 8 µ m in section with cilia to 6 µ m long. The distal edge of the epithelium is strongly eosinophilic. Dermal and adenal rhabdites absent. Anterior kidney-shaped eyes present and consisting of numerous small (ca 1–2 µ m) black pigment granules. Ventral and slightly posterior to the eyes is a vertically orientated pharynx rosulatus to 58 µ m long and 46 µ m wide ( figure 3 View FIG ). The pharynx has a slight posterior incline. In cross-section, approximately 20 columnar cells are present, each ca 9 µ m high with translucent cytoplasm and a basal nucleus. Posteriorly, the pharynx leads into a short oesophagus and a sac-shaped gut that extends to about three-quarters of the body length. In section, gut cells are either translucent or highly eosinophilic and to 12 µ m high. Some cells are shaped as inverted goblets. Diatoms were regularly present in the gut lumen. Subepidermal musculature consists of circular and longitudinal fibres. In one crosssection, approximately 10 longitudinal muscles could be counted in a 50 µ m span. Caudal adhesive glands absent. Protonephridia difficult to identify in most specimens but appear to branch posterior to pharynx and open separately behind mouth.

Male reproductive system. A single elongate testis is present immediately behind the pharynx and ventral to the vitellaria ( figure 3 View FIG ). The testis is orientated transversely but curved along its length. The exact position of the testis is somewhat variable in living specimens. The left side is a compact germinal zone while free sperm are present along the curve and anterior portion of the testis. The entire testis is lined with circular musculature. In cross-section, the testis is 24 µ m diameter. Anteriorly, the testis leads into a slightly more dorsal vesicula granulorum, also curved. The vesicula granulorum is highly elongate and bent at ca 50% length ( figure 4A, B, D View FIG ). Externally, it is lined with thick (3 µ m) spiral muscles, and internally, masses of small (1 µ m), circular, eosinophilic secretions are present along the entire length ( figure 4C, D View FIG ). The spiral musculature of the vesicula granulorum is continuous with the male genital canal that houses a sclerotic stylet. The spiral musculature of the canal, however, is more circularly orientated, thinner (1–2 µ m), and also lines a series of longitudinal muscles. Circular muscles do not extend down to the atrium, but stop at the distal end of the stylet. The eosinophilic secretions of the vesicula granulorum are present in the proximal opening of the canal and stylet, and masses of secretions (presumably as compact glands) are present outside the male canal on either side ( figures 4C View FIG , 5A View FIG ). The stylet is an elongate tubular organ, to 108 µ m long, with two slight bends along its length ( figure 5B View FIG , 6 View FIG ). The proximal opening is rimmed and up to 15 µ m wide. Approximately 3 µ m from the opening is an external ring followed by a pair of shark fin-shaped structures (9 µ m long) on either side. The stylet narrows to 11 µ m at ca 50% length. Close to the distal end is a bendable lip-like structure to 54 µ m long. When in the male canal, the lip-like structure is bent back along the length of the stylet. During fixation, the lip unfolds from the stylet.

Female reproductive system. The female organs include paired vitellaria, a single ovary, bursa, and uterus ( figure 3 View FIG ). Paired vitellaria extend from 30% body length to the posterior one-third of the body. Vitellaria are compact eosinophilic strands, approximately 15 µ m high by 10 µ m wide in section, and ventro-lateral to the gut. Caudally, the vitellaria connect to the common female genital canal close to the site of the ovary. The canal is highly muscular with thick walls surrounded by longitudinal muscles ( figures 3 View FIG , 7 View FIG ). Distally, the canal leads into a uterus. The walls of the uterus were lined with longitudinal muscles extending from the female canal. A light, alcian blue-staining flocculent material was always present in the lumen of the uterus. Proximal to the uterus and ovary is an elongate bursa, sheathed in longitudinal muscle, and partially collapsed in all specimens examined.

Cladistics. Eleven characters were assembled for cladistic analysis ( tables 1, 2). A heuristic search found seven most parsimonious trees (Length = 19, Consistency Index = 0.684, Retention Index = 0.647). The strict consensus tree placed Phaenocorinae as the most basal subfamily within the Typhloplanidae with Cephalopharynginae as the sister group to the remaining seven families ( figure 8 View FIG ). Typhloplaninae and Mesostominae were sister taxa with 55% bootstrap support. There was 67% bootstrap support for Cephalopharynginae plus the remaining seven families. Selective exclusion of protonephridial characters (3 and 4) resulted in a single most parsimonious tree ( figure 9A; L View FIG = 14, CI = 0.625, RI = 0.571). Removal of characters pertaining to the testes (8–10) resulted in 20 most parsimonious trees ( figure 9B; L View FIG = 14, CI = 0.714, RI = 0.636). Exclusion of pharyngeal characters (1 and 2) resulted in 43 most parsimonious trees with minimal resolution of ingroup relationships in a strict consensus tree (L = 16, CI = 0.625, RI = 0.571).

Increasing the number of heuristic replications to 10 000 failed to find additional trees. A branch and bound search was also employed in PAUP but resulted in the same number of trees and same tree topology as the original heuristic search. An exhaustive search also found seven most parsimonious trees with shortest length of 19.