Saltipedis (Spinosaltipedis)

Morales-Núñez, Andrés G., Heard, Richard W. & Alfaro, Mónica, 2010, Saltipedis (Spinosaltipedis) puertoricensis, a new subgenus and species of apseudomorphan (Crustacea: Tanaidacea: Parapseudidae) from coastal waters off Culebra Island, Puerto Rico, with keys and taxonomic observations, Zootaxa 2578, pp. 25-46 : 28

Subgenus Saltipedis (Spinosaltipedis) , new subgenus

Diagnosis: Parapseudidae , Parapseudini , Saltipedis sensu lato. Epistomal spine appearing absent. Surface of mandible between base of palp and molar process with six to seven distinctive, well-developed, buttressed, naked setae ( Fig. 3 E). Epignath with seta on inner subdistal margin minute (vestigial); length less than 1/8 width of epignath ( Fig. 4 E).

Type species: Saltipedis puertoricensis , n. sp.

Etymology: From the Greek word Spino = referring to spines on mandible + Saltipedis

Remarks: The Spinosaltipedis , n. subgen., is characterized by a combination of the presence of unique and distinctive accessory spiniform setae on the mandible and the lack of an epistomal spine. The lack of an epistomal spine falls within Saltipedis sensu lato since it is also apparently absent on S. (S.) achondroplasia (R. Bamber, per. com. July 2009). The setation of basal article of the uropod and pleotelson ( Fig. 2 D) may represent additional characters, but this cannot be confirmed until reexamination of the species within the subgenus Saltipedis . Pending the results of future morphological and molecular systematic/phylogenetic studies for the taxa within the family Parapseudidae and related groups, we tentatively place the new Puerto Rican subgenus within the genus Saltipedis sensu lato. Though readily distinguished from the other species within the genus, the subgeneric status of S. tetracanthus Guţu and Angsupanich, 2004 remains unsettled, pending the a detailed description of its mouth parts and maxilliped.

The generic status of the Longipedis erected by Larsen and Shimomura (2006) is problematic. Like other members of the similar genus Podictenius Guţu, 2006 , it apparently lacks a dorsal transverse row of setae on the dorsum of the first abdominal segment, which we tentatively consider a pivotal unifying character for the genus Saltipedis . For this reason, we resurrect the monotypic genus Longipedis for which L. fragilis was originally designated as the type species.

In some parapseudid taxa, however, the presence of a dorsotransverse row of setae on the first abdominal segment may be variable. For example, in genus Parapseudes it is present in P. latifrons sensu Lang 1966 and P. arenamans Larsen and Shimomura, 2008 , but is lacking or dorsally incomplete on P. a l g i c o l a (Shiino, 1952); P. neglectus Miller, 1940 (R. Heard, per. obser.) and P. pedispinis (Boone, 1923) (see Menzies 1953), and apparently P. trispinosus Guţu, 1998 (see Guţu 1998).

The occurrence of mandibular accessory setae and a dorsotransverse row of setae on the first abdominal segment distinguish Spinosaltipedis from the otherwise similar western Atlantic members of Podictenius Guţu, 2006 . Like Spinosaltipedis , two of three nominal species of Podictenius , P. e s p i n o s u s (Moore, 1901) and P. tomiliffei Guţu, 2006 , are known only from the tropical waters of the western Atlantic. The third species, P. estafricanus Guţu, 2006 , which appears quite different from its two Atlantic congeners, is known from the western Indian Ocean ( Guţu 2006). Guţu (2006) considered the presence of prominent row of spiniform setae along the anteroproximal margin of the basis for the first pereopod an important generic character. Although the first pereopod of Spinosaltipedis has a few such setae, they are smaller and less distinctive than the illustration of Moore (1901: Plate 7, fig. 4). Also, Spinosaltipedis is differentiated from Podictenius by having the first pereopod bearing short, blunt conical spiniform setae (instead of acute, elongate spiniform setae) on the margins of the carpus and propodus; however, species with both these setal conditions on the first pereopod occur within the subgenus Saltipedis (see Figure 7 ).

Based on the current state of knowledge and complexity of apsudomorphan taxonomy, we believe that many of the supraspecific taxonomic designations (e.g., genera, subfamilies, and families) maybe based upon, or at least in part upon, convergent or independently derived characters. For these reasons the taxa within the suborder should be the subjects of future systematic revisions.

Figures

FIGURE 2. Saltipedis (Spinosaltipedis) puertoricensis n. subgen., n. sp., Adult female A, B, D, F, Adult male C, E, G. A, body, dorsal view; B, enlargement of rostrum; C, lateral aspect of adult male body showing hyposphaenia; D, enlargement of pleotelson; E, antennule, male; F, inner flagellum, female; G, antenna, male. Scale line: A = 1.0 mm; C = 0.3 mm; E – G = 0.5 mm.

FIGURE 3. Saltipedis (Spinosaltipedis) puertoricensis n. subgen., n. sp., Adult Female. A, labrum; B, right mandible; C, left mandible; D, enlargement of lacinia mobilis and tip of incisor process; E, mandible, excluding molar process, showing accessory setae; F, maxillule; G, maxilla; H, enlargement of trifurcate setae; I, labium. Scale line: A and F = 0.1 mm; B, C and E, = 0.5 mm; G and I = 0.2 mm.

FIGURE 4. Saltipedis (Spinosaltipedis) puertoricensis n. subgen., n. sp., Adult Female. Maxilliped A – D: A, Maxilliped showing setation; B, inner face with inner plate, most setae excluded; C, inner plate; D, enlargement of spiniform setae from different aspect; E, epignath. Scale line: A = 0.2 mm; F = 0.1 mm.

FIGURE 7. Known first pereopods for species of the genus Saltipedis. Except for exopods on B and E, all setae and exopods are illustrated. A, Saltipedis paulensis; B, S. robustispinosus; C, S. bacescui; D, S. navassensis; E, S. achondroplasia; F, S. tetracanthus; G, S. puertoricensis. [Figures modified from: Guţu 1996 (A – B); Guţu 1998 (C); Hansknecht et al. 2001 (D); Bamber et al. 2003 (E); and Guţu and Angsupanich 2004 (F)].