Liropus guerragarciai, Mauro, Fábio Da Motta & Serejo, Cristiana Silveira, 2015

Mauro, Fábio Da Motta & Serejo, Cristiana Silveira, 2015, The family Caprellidae (Amphipoda: Caprelloidea: Caprellidae) from Campos Basin, Southwestern Atlantic, with a key of species occurring in Brazil, Zootaxa 4006 (1), pp. 103-127 : 110-114

publication ID	https://doi.org/ 10.11646/zootaxa.4006.1.5
publication LSID	lsid:zoobank.org:pub:DE692C37-9B70-468E-8AF1-E5BA03AB2918
DOI	https://doi.org/10.5281/zenodo.5272830
persistent identifier	https://treatment.plazi.org/id/03C58794-BF74-FFAE-FF1D-FB77D7F83AAF
treatment provided by	Plazi
scientific name	Liropus guerragarciai
status	sp. nov.

Treatment

Liropus guerragarciai View in CoL sp. nov.

( Figs. 4–6 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Material examined: 1 male holotype, 4.29mm, 22º 40' 58,651" S 40º 17' 38,462" W, 988m, MNRJ 24705; 1 allotype female, 22º 40' 58,651" S 40º 17' 38,462" W, 988m, MNRJ 24706; 1 male, 23º10´22,254"S 40º 56´46,365", 1335m; MNRJ 24707; 1 juvenile, 23º45´18,413"S, 2423m, MNRJ 24778; 2 females, 39º 44' 21,079" W, 1932m, MNRJ 24775; 1 female, 1 juvenile, 21º41´12, 557"S 40º1´56,073”W, 702m, MNRJ 24777; 1 male, 1 female, 1 juvenile, 23º 1´30, 862"S 40º45´22, 948"W, 964m, MNRJ 24776; 1 male 23º 13' 46,474" S 40º 55' 56,178" W, 986m, MNRJ 24707; 1 male, 21º 41' 12,557" S 40º 1' 56,073" W, 702m, MNRJ 24708.

Diagnosis. Antenna 2 flagellum 2-articulate with triangular process at distal part of article; head and pereonites projections absent; gnathopod 2 basis with proximal constriction; male with 1 pair of lobes and 1 pair of 2– articulate well developed appendages, pereopod 5 3-articulate. Pereonite 2 1.5x basis of gnathopod 2; pereonites 2– 7 up to five times longer than wide; body slender; pereopods 3–4 subequal in length and width; gills elliptical and reduced; abdomen with 1 pair of 2-articulate well developed appendages.

Description. Male, holotype, 4.29mm. Head: Antennae: Antenna 1 flagellum 4-articulate, 1.25 times longer than antenna 2; Antenna 1 and Antenna 2 first articles peduncle with distal acute projection; flagellum 4-articulate; Antenna 2 first article with distal-lateral triangular projection; flagellum 2-articulate. Left mandible incisor 5- toothed; lacinia mobilis 5-toothed; row of three pectinate setae laterally; molar conspicuous with five small teeth, little differentiated; palp second article with 1 distal-lateral setae; last article with formula 1-5-7-1. Right mandible with 5 acute tooth; lacinia mobilis strongly serrate; palp distal part with row of 5 stocky projections and row of 10 setae; molar strong. Lower lip with inner and outer lobes well marked, inner lobes strongly round and outer lobes stronger and somewhat elliptical. Maxilliped inner lobe smaller than outer lobe; outer lobe with row of six setae; palp second article with one distal setae, second article with four distal setae, last article inner margin with several small serrate setae and one distal setae. Maxilla 1 outer lobe with five denticulate setae, palp with five setae.

Thorax: Gnathopod 1 ischium and merus subequal in length; carpus about 1.5 times longer than merus with row of six setae distally; propodus with sub-ventral row of five small setae, and a row of five large setae at medialdistal part; palm serrate; dactylus reaching end of propodus, smooth. Gnathopod 2 basis with proximal constriction, ischium 0.6 times size of merus, carpus smaller; palm with several micro-setae ventrally, with proximal robust seta, a small concavity followed by an acute teeth and an acute concavity. Pereopods 3 and 4 1-articulate with pair of apical setae. Pereopod 5 article 2 the largest, article 3 minute, bearing two small setae. Pereopods 6 and 7 missing.

Abdomen: Male with 1 pair of lobes and 1 pair of 2-articulate well developed appendages.

Female, allotype, 4.12mm. Body smooth; antenna 2 peduncle surpassing antenna 1 peduncle; oostegites strongly setose; oval projection at mid-length of pereonite 5. Gnathopod 2: ischium with 3 mid-lateral setae; twice as long as merus; merus rounded ventrally; propodus with small cavity; palm weakly serrate; dactylus smooth.

Distribution. Campos Basin, Brazil, 702–2423m.

Etymology. Species is named in honor to Dr. José Manuel Guerra-García, after his vast contribution to the knowledge of caprellid amphipods.

Remarks. Liropus is composed by ten species (including the present material), with a single previous record for Brazil, L. nelsonae ( Guerra-García, 2003a). Liropus guerragarciai sp. nov can be assigned to Liropus for the following characters: body elongate; head and pereonites lacking spines or projections; pereopods 3–4 1-articulate; pereopod 5 reduced (and less than 5-articulate) and medially inserted; male abdomen appendages present and strongly reduced, female with a pair of lobes and no appendages. Guerra-García & Hendrycks (2013) described L. minusculus for the Eastern Pacific and comment on the distribution of the genus Liropus . Five species occur in the Altantic Ocean, two in the Mediterranean Sea and two in the Pacific Ocean. From the ten species known, eight have ommatidia ( Table 3 View TABLE 3 ). Liropus guerragarciai sp. nov. is close related to L. nelsonae Guerra-García, 2003 in a 3-articulate pereopod 5, but differs as abdomen lobes and appendages are well developed and fully 2-articulate (versus vestigial, rudimentary). It also resembles L. elongatus Mayer, 1890 , L. gracilis Chevreaux, 1927 and L. minimus Mayer, 1890 in a smooth and strongly elongate body and the presence of a sharp constriction on basis of gnathopod 2 that bends the appendage forward or backwards. Liropus guerragarciai sp. nov. can be distinguished from L. minimus and L. elongatus in pereopod 5 3-articulate (versus 2-articulate) ( Table 3 View TABLE 3 ). Liropus nelsonae was recorded at depths from 900 to 1000m from off Pernambuco state ( Guerra-García, 2003a). Liropus guerragarciai sp. nov. has been recorded at similar depths (700–1900m) and was the only caprellid species to be found at this bathyal range in the HABITATs Project at the Campos Basin, Rio de Janeiro.