Balaenocyamus, Iwasa-Arai & Serejo, 2018

Iwasa-Arai, Tammy & Serejo, Cristiana Silveira, 2018, Phylogenetic analysis of the family Cyamidae (Crustacea: Amphipoda): a review based on morphological characters, Zoological Journal of the Linnean Society 184, pp. 66-94 : 90

BALAENOCYAMUS GEN. NOV.

Diagnosis: Incisor of left mandible with six teeth, right incisor with seven teeth; lower lips inner lobes fully fused. Palm of gnathopod 1 with a broad proximal expansion. Pereonites 3 and 4 narrower than pereonite 5 in males and subequal in width in females. Pereonite 4 of male without posterolateral knoblike process. Accessory gills spinelike in males and absent in females.

Type species: Cyamus balaenopterae (KH Barnard, 1931) .

Etymology: The specific epithet refers to the hosts associated with this genus, the family Balaenopteridae Gray, 1864 .

Remarks: In contrast to Cyamus species, which are usually host specific, Balaenocyamus gen. nov. is more widespread and is found on large baleen whales of the family Balaenopteridae , such as Balaenoptera musculus , B. physallus and B. acutorostrata . Balaenocyamus gen. nov. differs from Cyamus , by: (1) incisor with six teeth (vs. five teeth); (2) lower lip inner lobes fully fused (vs. partly fused); (3) pereonites 3 and 4 narrower than pereonite 5 in males and subequal in width in females (vs. pereonites 3 and 4 wider or subequal in width to pereonite 5 in males and wider in females); (4) accessory gills spinelike in males and absent in females (vs. accessory gills usually bilobed in males and usually present in females); and (5) pereonite 4 of male straight, without posterolateral knoblike process (vs. pereonite 4 of male with a posterolateral knoblike process). Haney (1999) also found B. balaenopterae comb. nov. to be a basal group of Cyamus and commented on its plesiomorphic character states, suggesting B. balaenopterae comb. nov. to be an intermediate between Cyamidae and Caprellidae , according to its general morphology.

Although the position of B. balaenopterae within Mysticyaminae subfam. nov. has low statistical support (clade 3), the subfamily was recovered in all analyses, and most of the representatives of Mysticyaminae subfam. nov. are found parasitizing mysticetes.