Pseudoleptochelia Lang, 1973

Morales-Núñez, Andrés G., Heard, Richard W. & Alfaro, Mónica, 2013, A new species of Pseudoleptochelia Lang, 1973 (Crustacea: Peracarida: Tanaidacea: Leptocheliidae) from the Northwest Atlantic with observations on the status of the genus, Zootaxa 3664 (2), pp. 259-282 : 261-263

Genus Pseudoleptochelia Lang, 1973

Revised diagnosis. Male: Functional mouth parts lost (atrophied mass). Maxilliped greatly reduced, vestigial, basis represented by small cluster of simple setae, palps greatly reduced, partially fused. Antennule with peduncular article-3 reduced, forming dorsal saddle-like protrusion over flagellum article-1; flagellum with 8–14 aesthetascbearing articles, and minute terminal article with simple setae. Cheliped appearing subchelate, fixed finger reduced to small distal process; carpus with or without inferior process. Uropod with endopod having four to five (usually four) articles or incipient articles; exopod unarticulated.

Female: Antennule compressed, stout, broad at base; composed of three apparent articles, plus minute terminal article. Antenna with article-2 having simple dorsodistal setae (lacking buttressed spiniform setae), article-3 anterodorsal distal margin with simple seta only. Maxillule spines slender. Maxilliped bases unfused distally with sub-distal margin having 3 to 5 simple setae reaching past article-1 of palp. Cheliped with coxal sclerite isolated, not reaching posterior of cephalothorax; disto-lateral margin of carpus extending as cuff to overlap propodus. Pereopod-1 unguis as long as or longer than dactylus. Pereopods 4 to 6 with basis swollen; merus distal margin with pair of basally-swollen, distally attenuated setae (appearing setulate); carpus with stout, sometimes weakly bidentate and/or setulate setae. Uropod with endopod having four to five (usually four) articles or incipient articles; exopod uniarticulate.

Type species: Pseudoleptochelia anomala (Sars, 1882) .

Other species: Pseudoleptochelia fairgo Bamber, 2005 ; P. juliae , n. sp.; P. magna (Smith, 1906) ; P. mortenseni Lang, 1973 ; P. occiporta Błaźewicz-Paszkowycz & Bamber (2012) ; P. straddi Bamber, 2008 .

Remarks. The original description and illustrations for Heterotanais anomalus are based solely on two male specimens (Sars 1882, 1886) collected from off Messina, in the Mediterranean. Lang (1973) extracted this species from Heterotanais Sars 1882 to become the type species of the genus Pseudoleptochelia Lang, 1973 . In addition to the type species, P. anomala, Lang transferred seven additional species, Heterotanais antarcticus Lang, 1953 ; H. magnus Smith, 1906 ; H. provincialis Dollfus, 1898 ; H. inermis Dollfus, 1898 ; H. mercantilis Smith, 1906 ; H. mergellinae Smith, 1906 ; and Leptochelia filum (Stimpson, 1853) to Pseudoleptochelia (see Table 1 ). In the same publication he also described a ninth species, P. mortenseni from the southern Caribbean Sea ( Tobago). Since then, six additional species have been added to the genus (see Table 1 ): P. anorexia Bird & Bamber, 2000 ; P. b u l b u s Bamber, 2006; P. fairgo ; P. longidactylus (Bäcescu, 1977) , P. straddi and P. occiporta Błaźewicz-Paszkowycz & Bamber, 2012 . The 15 nominal species presently attributed to Pseudoleptochelia appear to comprise a heterogeneous grouping, which is in need of revision (Błaźewicz-Paszkowycz & Bamber 2012).

When Lang (1973) designated Heterotanais anomalus as the type species for Pseudoleptochelia , he did not have type or topotypical material available, thus as part of his generic diagnosis he incorrectly included features of what he believed to be the female of the non-type species P. mortenseni , described from Tobago in the same publication and as part of the generic diagnosis. It is our opinion that this part of Lang’s diagnosis has no taxonomic standing since it is not based, at least in part, on the female of the type species, P. anomala . Further, based on our review of the literature and the examination of other leptocheliid genera and species, we believe that the female diagnosed and ascribed to P. mortenseni belongs to a different genus. Ideally the original generic diagnosis for the genus should have been based on the original description of H. anomalus Sars, 1882 and males and females attributable to the species from the Mediterranean and supplemented with observations on the male holotype of P. mortenseni . Notwithstanding the lack of a female, the text and illustrations provided by Sars (1882 and 1886, respectively) for the male type are adequate to demonstrate its uniqueness and specific validity. Later, based on material from the Mediterranean Sea collected near Naples, Smith (1906) presented an illustrated supplemental description of H. anomalus and more recently Riggio (1996) reported this species from Italian waters as P. anomala . In spite of these efforts, no female has been well-enough described to be definitely confirmed as that of P. anomala . The female illustrated and attributed to P. anomala sensu Riggio (1996) appears to represent a species of Leptochelia sensu lato.

In summary, we consider the genus Pseudoleptochelia to be valid because Lang designated Heterotanais anomalus as the type for the genus. At the time of its generic designation, the unique characters exhibited by the male of H. anomalus fit the criteria of a valid genus.

Recently, males and females attributable to type species, P. anomala from the Mediterranean were independently made available to us and to Roger Bamber, who is preparing a detailed description of both sexes (R. Bamber, pers. comm.). Our and Roger Bamber’s specimens were both collected from the Spanish Balearic Islands, about 1000 km west of its type locality near Messina, Italy. Based on our examination of this Mediterranean material, we believe that the female attributed to P. mortenseni appears to represent a distinctly different genus.

Lang’s inappropriate diagnosis has led to confusion in separating females belonging to species within the genera Pseudoleptochelia , Pseudonototanais Lang, 1973 sensu lato, and Leptochelia sensu lato, especially when they were not accompanied by males. In effect, this facilitated the transformation of the genus into a “catch all” for some species that could not be placed reliably in other leptocheliid genera (e.g. Pseudoleptochelia filum sensu Sieg (1976) ; Pseudoleptochelia anomala sensu Riggio (1996) ; and Pseudoleptochelia anorexia ).

Compared to the revised generic diagnosis (see above), the female of P. mortenseni sensu Lang (1973) is characterized by (1) having the first antennular article-1 elongate, (2) the antenna having buttressed thorn setae and a distal dorsal spiniform process, respectively, on articles 2 and 3, (3) only two pairs of long simple setae on the sub-distal margin of the maxillipedal basis, (4) the cheliped lacking a cuff on the disto-lateral face of the propodus, and (5) the merus of pereopods 4–6 apparently lacking a pair of proximally swollen and distally attenuated setae. We believe that the female attributed to P. mortenseni by Lang (1973) may represent an unnamed species, possibly belonging to a putative new Leptochelia sensu lato or a Pseudonototanais -like genus.

In contrast, the antennule in Lang’s figure 16g, which he attributes to an immature female stage of P. mortenseni , appears to represent that of the true female for this species and is similar to that of P. anomala material examined by us. Notwithstanding, Lang’s description and illustrations for the male of P. mortenseni support its congeneric status with the type species, P. anomala .

The females for P. anomala (examined during the present study), P. fairgo , and the new species described herein as well as those of the similar genera Konarus Bamber, 2006 and Parakonarus Bird, 2011 , and to a lesser extent the apparently more highly derived genus Makraleptochelia Araújo-Silva & Larsen, 2012 , share a number of similar characters. These include: Antennule composed of three apparent articles, plus vestige of minute terminal article; article-1 broad in dorsal aspect with length slightly greater than breadth. Antenna with article-2 having simple dorsodistal seta (lacking buttressed spiniform seta), article-3 anteriodorsal distal margin with simple seta only (no distal spinose process present). Maxilliped bases with sub-distal margin bearing 3 to 5 simple setae reaching past article-1 of palp. Cheliped with coxal sclerite isolated, not reaching posterior of cephalothorax; distolateral margin of carpus extending as cuff to overlap propodus. Pereopod -1 unguis as long as or longer than dactylus.

We consider the carpal process on the males of P. juliae , P. f a i rg o, and P. occiporta to be a specific or subgeneric rather than generic character and believe that these two species are congeneric with P. anomala , P. magna , P. mortenseni , and P. straddi . The possibility remains, however, that the presence or absence of a prominent carpal process, in combination with other less pronounced morphological features (e.g. setation of pereopods 4–6) may have systematic importance and, if so, more than one genus may be represented (G. Bird, pers. comm. Feb 2011). We concur with this possibility, but for the present include P. juliae , P. f a i rg o, and P. occiporta within Pseudoleptochelia . The taxonomic status the male and female of P. occiporta , recently described from Bass Strait, Australia in not treated here, but will be clarified in a forthcoming revision of the group by R. Bamber (pers. comm. 2013).

Tables

TABLE 1. Alphabetical listing of the 15 previously recognized species for the genus Pseudoleptochelia sensu lato, including information on distribution and depth range (based on Bird & Bamber, 2000; Anderson 2012).

Species anomala (Sars, 1882) [type species]	Geographical area Mediterranean (Messina); Indian Ocean (Zanzibar)	Depth range (m)?–37
anorexia Bird & Bamber, 2000	Indo-Pacific (South China Sea)	10–30
antarcticus (Lang, 1953)	SW Antarctic (Falkland Island)	0–358
bulbus Bamber, 2006	New Caledonia (Loyalty Islands)	12–20
fairgo Bamber, 2005	Australia (Esperance, Queensland)	23–39
filum (Stimpson, 1853) inermis (Dollfus, 1898) longidactylus (Bäcescu, 1977)	NE Pacific (NZ), US Pacific coast NE Atlantic (Dakar) Mediterranean (Libya)	0.5–138 7 70
magna (Smith, 1906)	Mediterranean (Naples)	Littoral
mercantilis (Smith, 1906)	Mediterranean (Naples)	Littoral
mergellinae (Smith, 1906)	Mediterranean (Naples)	Littoral
mortenseni Lang, 1973	Caribbean (Tobago)	Littoral
occiporta Błażewicz-Paszkowycz & Bamber, 2012	Australia (Western Port)	3−51
provincialis (Dollfus, 1898)	Mediterranean (St. Tropez)	50
straddi Bamber, 2008	Australia (Queensland)	10