Mayerella sittropiae, 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 : 114-120

Mayerella sittropiae sp. nov.

( Figs 7–9 )

Type material: 1 holotype male, 4,2 mm; 23º 11' 24,528" S 41º 0' 55,554" W, 106m, MNRJ 23497; 1 allotype female, 4.8mm, 1 paratype male; MNRJ 23498; 1 juvenile male, 22º 4' 9,756" S 40º 7' 5,747" W, 92m, MNRJ 23496; 1 male, 21º 17' 27,528" S, 40º 48' 27,096" W, 24m, MNRJ 23497; 1 female, 22º6´17,478" 40º43´45,6" W, 47m, MNRJ 23499; 1 juvenile male, 22º59 42,927" 41º21´13, 812” W, 77m, MNRJ 23500.

Diagnosis. Antenna 1 8-articulate, subequal in length to antenna 2 in both sexes; male gnathopod 2 basis length subequal to pereonite 2; penis papillae width and length subequal, apex pointed; male appendages more than 2x longer than wide, 2-articulate.

Description. Male, holotype, 4.2 mm. Head: Maxilla 1 outer plate with five pectinate setae and three small setae; palp with five simple setae; maxilla 2 inner lobe with six setae, outer lobe with five setae; left mandible incisor 5-toothed; lacinia mobilis 5-toothed and row of three serrate setae laterally; molar well developed; palp 3- articulate, article 2 with two setae; distal one twice as long than article 1; terminal article with one distal setae; right mandible incisor 5-toothed; lacinia mobilis 5-toothed; two lateral setae; labrum mid-apical portion with 5 diminute setae; maxilliped palp article 3 with rows of large setae (three lateral ones + for mid-center); article 4 with two apical setae; inner lobe with two plumose apical setae flanked by two simple setae; outer lobe with row of tree setae.

Thorax: Gnathopod 1 ischium half the length of merus; merus with three setae, about 0,8 times width of carpus; carpus with five ventral setae; propodus palm serrate, with row of seven medial setae; dactylus weakly serrate. Gnathopod 2 ischium 1.5 times longer than merus, rounded ventrally; propodus largest width at medial part, 1.25 times wider than proximal part; dactylus smooth; with row of diminute setae. Gnathopod 2 ischium with ventral setae, width and length subequal to merus; merus with 3 ventral setae; carpus reduced; propodus semirectangular, propodus palm smooth, with up to six setae, with one proximal stout setae. Pereopod 3 2-articulate, last article with four setae. Pereopod 5 4-articulate, first article two times longer than wide; last article with four setae. Pereopod 6 ischium two times as long as the merus; merus 1.25 times longer than wide; carpus with one plumose distal setae, subequal in length to propodus; propopdus with at least six ventral setae and five dorsal plumose setae; dactylus serrate.

Abdomen: Penis papillae minute; pair of lobes with two setae each; appendages 2-articulate, very elongate; much longer than wide, with hook pappilae in apex, surpassing abdomen tip.

Female, allotype, 4.8mm. Antenna 1 subequal in length to antenna 2, comprising 2/3 of body length; flagellum 6-articulate; antenna 2 flagellum 2-articulate; head notch present. Abdomen with three apical setae; pair of lobes, each with 3–5 small setae.

Gnathopod 2 dactylus strongly curved slightly slightly curved;shorter slightly curved; slightly curved slightly curved shorter

curved;shorter than than propodus lenght subequal to shorter than than propodus propodus propodus propodus

lenght

Distribution. Campos Basin, Brazil, 24– 106m.

Etymology. Species is named after the colleague Msc. Daniela Sittrop, who was the first researcher to work with the Caprellidae samples from Campos Basin in the Carcinology Lab of Museu Nacional/UFRJ.

Remarks. Until the present study Mayerella comprises five species and there are no previous records for Brazil ( Guerra-García, 2003c). In the same work, Guerra-García redescribed M. magellanica McCain & Grain, 1971 from Subantartic, Southeastern Pacific and compared with the four other previously known species within the genus: M. limicola Huntsman, 1915 and M. redunca McCain, 1968 , both from Western North Atlantic, M. acanthopoda Benedict, 1977 and M. banksia Laubitz, 1970 from the Northeastern Pacific. In the present study, M. sittropiae sp. nov. enlarges the distribution of the genus to the Southwestern Atlantic. Comparing with the other five species of the genus, M. sittropiae sp. nov. resembles Mayerella redunca in its male abdomen appendages at least 5 times longer than wide, and to M. magellanica in the 4-articulate pereopod 5 ( Table 4 ). It differs from M. redunca for the male gill plates minute (versus strongly elliptical and well developed) and male abdomen appendage surpassing more than 2 times abdomen apex (versus reaching apex) even in young male, and from M. magellanica in male gnathopod 2 with basis not projected (versus acutely projected distally) and propodus medial part about 2 times longer than wide (versus medial part more than 3 times longer than wide). Morphological comparison between the six known Mayerella species is given ( Table 4 ).

Figures

FIGURE 7. Mayerella sittropiae sp. nov., male, holotype, 4.2 mm, Campos Basin, RJ, MNRJ 23497. Scale bar: habitus = 0.5 mm; mx 1, mx 2, mdb (l), mdb (p), lbr, mxp = 0.1 mm.

FIGURE 8. Mayerella sittropiae sp. nov., male, holotype, 4.2 mm, Campos Basin, RJ, MNRJ 23497. Scale bar: gn 1, gn 2, p 5, p 6, abd = 0.1 mm.

FIGURE 9. Mayerella sittropiae sp. nov., allotype, female, 4.8 mm, Campos Basin, RJ, MNRJ 23498. Scale bar: habitus = 0.3 mm; gn 2, abd = 0.1 mm.

Tables

TABLE 4. Morphological comparison of world Mayerella species.

Characters	M. acanthopoda	M. banksia M. magellanica	M. limicola M. redunca	M. sittropiae sp. nov.
Gnathopod 2 insertion	posterior half of pereonite 2	posterior half of posterior half of pereonite 2 pereonite 2	anterior half of posterior half of pereonite 2 pereonite 2	posterior half of pereonite 2
Gnathopod 2 basis	subequal to pereonite 2	subequal to pereonite distincly longer 2 thanpereonite 2	subequal to shorter than pereonite 2 pereonite 2 lenght	subequal to pereonite 2 lenght