Cacoheterotanais Morales-Núñez & Heard, 2015, gen. n.
Creators: name: Morales-Núñez, Andrés G.
name: Heard, Richard W.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Tanaidacea
Leptocheliidae
Cacoheterotanais

description: Cacoheterotanais gen. n.
Synonymy. “ Pseudonototanais sp. B”: Heard et al. (2004); Morales-Núñez & Heard (2013).
Diagnosis. Male: Antennule with peduncle having three articles; flagellum with three articles, article-1 with proximal and distal cluster of aesthetascs; article-2 with distal cluster aesthetascs; article-3 minute, terminating with four simple setae of varying length. Antenna with one mid-dorsal and two distal (one dorsal and one ventral) setiform spines on the second article. Buccal mass (mouthparts) obsolete. Maxilliped reduced, appearing nonfunctional. Cheliped forcipate with carpus lateral face having length greater than depth; propodus with length about Character Cocotanais Heterotanais Makassaritanai s Ogleus Pseudonototanais Cacoheterotanais gen. n. Antennule
peduncle
3 articles 3 articles 3 articles 3 articles 2 articles 3 articles twice depth, ventro-distal margin with pair of subacute processes (one disto-laterally and other disto-medially) to seat long, slightly curved dactylus when closed; fixed finger of propodus directed downward, nearly at right angle to posterior (ventral) margin of propodus, with low tooth or apophysis sub-distally on incisive margin. Uropodal endopod with three subequal articles; exopod uni-articulate, small not reaching past endopodal article-1.
Female: Maxilliped with inner plate having three pairs of long simple setae distally. Uropodal endopod, as in male, with three articles.
Type species. Cacoheterotanais rogerbamberi sp. n.
Etymology. From the Greek Cacos = bad, plus the generic name Heterotanais.
Gender. Masculine.
Known range. North America, Gulf of Mexico, Eastern Continental shelf off the Florida West Coast.
Remarks. Systematically, the genera within the Pseudonototanais complex (i.e. Cocotanais; Makassaritanais; Ogleus Morales-Núñez & Heard, 2013; Pseudonototanais and Heterotanais) appear to represent a highly derived group displaying a mixture of characters (see Table 1) confounded by the probability of homoplasy. Cacoheterotanais shares a unique combination of some of these characters.
The males of Cacoheterotanais and Pseudonototanais have an antennule with three flagella articles, uropods with three endopodal articles, and article-2 of the antenna with three setiform spines, which appear to distinguish them the other male members of the genus-group. The male of the Cacoheterotanais differs from that of Pseudonototanais by having three instead of two apparent antennular peduncle articles (Figs 10 G, A, respectively) and a chela with a distinctly different fixed finger. The male of Cacoheterotanais, like those of Cocotanais, Makassaritanais, and Pseudonototanais, has an antennule with the first apparent flagella article bearing both proximal and distal clusters of aesthetascs (Figs 10 G, E, D–F, A, respectively). In contrast, only a single distal cluster of aesthetascs is present on first flagella article-1for the males within the genera Heterotanais and Ogleus (Figs 10 C, B, respectively). The chela for the male of Cacoheterotanais appears to be transitional between M. bamberi, and those of the genera Cocotanais and Pseudonototanais. The latter two genera lack the sub-distal apophysis or low blunt tooth on the subdistal grasping margin of the fixed finger (Figs 11 E, C, A, respectively). This structure is present in Makassaritanais, Ogleus, and Cacoheterotanais (Figures 11 D, F, B, G, respectively) and maybe homologous with the “teeth” occurring on the fixed finger of males within genus Leptochelia sensu lato. Table 1 presents a synopsis of these and additional characters for separating the genera within the Pseudonototanais complex. The female of Cacoheterotanais differs from those of other genera of the complex by having its uropodal endopod with three articles of similar length; those for the other genera have from 4–5 articles or incipient articles often of variable length.
Cacoheterotanais and the other members of the Pseudonototanais complex appear to have more affinities of the Leptocheliinae than the other currently recognized subfamilies as defined by Bamber (2013). There, however, still appears to be confusion in the systematics of this genus-group (see Morales & Heard 2013). Based on the variable morphological features exhibited within it, the generic status of many of the species is uncertain; however, we reluctantly decided to establish the genus Cacoheterotanais to accommodate the new species from the Gulf of Mexico. The designation of a new genus within this group of six mostly monotypic genera is based on sound morphological differences, but at this time we are unable to determine whether or not they are systematically or phylogenetically definitive. Nevertheless, we follow Morales-Núñez & Heard (2013) in believing that until molecular studies can be conducted, the status of genera within the “ Pseudonototanais complex” (as well as for the Leptocheliidae as a whole), cannot be resolved with a high degree of certainty.
description: Published as part of Morales-Núñez, Andrés G. & Heard, Richard W., 2015, Cacoheterotanais rogerbamberi, a new genus and species of leptocheliid Tanaidacea (Crustacea: Peracarida) from shelf-waters of the Gulf of Mexico, pp. 169-188 in Zootaxa 3995 (1) on pages 170-172, DOI: 10.11646/zootaxa.3995.1.16, http://zenodo.org/record/235985