Synopsis of Ectodus Boulenger, 1898

Type species: Ectodus descampsii Boulenger, 1898

Distinctive characters:

• The body is elongated and spindle-shaped, 4-5 times as long as high.
• Dorsal fin contains 12-16 hard-rays and 13-15 soft rays; anal fin contains 3 hard rays and 8-10 soft rays.
• Scales large with 35-38 scales along the longitudinal line.
• Two lateral lines.
• Lower pharyngeal bone triangular covered densely with small fine sub-conical teeth.
• Teeth are conical arranged in 3-4 rows.
• The color of the body is silvery, with the throat, edge of the pelvic fins and caudal fin being black in sexually mature males. The dorsal fin is ornamented with a spot.
• Total length 15 cm

Species currently included:

Ectodus descampsii Boulenger, 1898

Type locality:

Lake Tanganyika

Synonyms:

Pelmatochromis stappersii Boulenger, 1914

Remarks on taxonomic status:

Apparently two Ectodus species are present in Lake Tanganyika; one distributed in the southern part of the Lake and one in the northern. One of these was described by Boulenger in 1898 and one is a potentially un-described species.

Which of the two Ectodus species Boulenger originally described in 1898 is surrounded with much confusion, as the exact find locality of the holotype are not known, according to Maréchal & Poll (1991) being just labeled “Lake Tanganyika” by Boulenger. Hitherto it has been assumed that the northern form was the true Ectodus descampsi and the southern form a closely related species that in the literature has been known under the name E. sp. “descampsii ndole”, since it first was recognized as a potentially undescribed species by Konings (1988; 1998). Recently Sébastien Verne has examined the collections at the Royal Africa Museum in Tervuren, Belgium and has confirmed that two species of Ectodus are present and quite surprisingly, that the holotype corresponds with the southern form (Verne 2001) – this topic is addressed in a separate paper.

Sturmbauer & Meyer´s molecular analyses (1993) showed that Ectodus may form a subclade together with Lestradea, Cunningtonia and Aulonocranus in the Ophthalmotilapia-clade, which also consists of the genera Cyathopharynx and Ophthalmotilapia. This has been confirmed by a recent molecular work, which has also shown that the genus Ectodus is the most ancestral branch in this subclade and confirmed the existence of two Ectodus species (Koblmüller et al. 2004).

Note: The above listed distinctive characters from Poll 1986 may in fact be refering to the undescribed northern form.