Metacirolana manuelae, Paiva & Souza–Filho, 2023

Paiva, Ricardo J. C. & Souza – Filho, Jesser F., 2023, Two new species of Metacirolana Kussakin, 1979 (Isopoda: Cirolanidae) from Brazilian waters, Journal of Natural History 57 (1 - 4), pp. 142-158 : 148-157

Metacirolana manuelae sp. nov.

( Figures 6–10 )

Material examined

Holotype. Female, REVIZEE III #40, 4.084°S, 37.417°W, 15 May 1998, 50 m, dredge, NOc Antares coll., MOUFPE 14959 .

Paratypes. 1 male, REVIZEE III #40, 04.084°S, 37.417°W, 15 May 1998, 50 m, dredge, NOc Antares coll ., MOUFPE 14843 . 1 male, BPOT I #13 A, 04.790°̎S, 36.386°W, 22 November 2003, 47.1 m, N . OC. Astro Garoupa coll ., MOUFPE 14755 . 6 males, 10 females, BPOT I #23 C, 04.617°S, 36.600°W, 23 November 2003, 21.8 m, N . Oc . Astro Garoupa coll ., MOUFPE 14782 . 1 male, BPOT I #30 B, 04.783°S, 36.650°W, 15 December 2003, 18.8 m, N . OC. Astro Garoupa coll ., MOUFPE 14776 . 1 male, 1 female, BPOT II #34 , 4.701S, 36.748°W, 20 May 2003, 24.3 m, dredge, N . Oc . Astro Garoupa coll ., MOUFPE 14827 . 2 males, 7 females, BPOT II #30 , 04.791°S, 36.656°W, 20 May 2003, 18.8 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14826 . 3 males, 7 females, 4 mancae, BPOT II #14 AM, 04.790°S, 36.386°W, 22 November 2003, 47.1 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14796 . 3 males, 8 females, BPOT II #6 , 04.881°S, 36.297°W, 21 November 2003, 17.1 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14789 . 1 male, BPOT II #06 AM, 04.790°S, 36.386°W, 21 November 2003, 17.1 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14788 . 1 females, 1 manca, BPOT II #34 AM, 04.701°S, 36.297°W, 24 November 2003, 24.3 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14790 . 1 male, BPOT II #14 AM, 04.790°S, 36.386°W, 22 November 2003, 47.1 m van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14793 . 2 females, BPOT II #12 , 04.881°S, 36.386°W, 22 November 2003, 13.7 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14794 . 1 male, BPOT IV #34 , 04.701°S, 36.386°W, 29 May 2004, 24.3 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14806 . 1 female, BPOT IV #30 , 04.791°S, 36.656°W, 28 May 2004, 18.8 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14799 . 14 males, 18 females, BPOT IV #23 , 04.790°S, 36.566°W, 27 May 2004, 21.8 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14800 . 2 mancae, BPOT IV #23 , 04.790°S, 36.566°W, 27 May 2004, 21.8 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14809 . 2 females, BPOT IV #13 , 04.790°S, 36.386°W, 26 May 2004, 47.1 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14807 . 5 males, 8 females, 2 mancae, BPOT IV #14 , 04.881°S, 36.476°W, 27 May 2004, 47.1 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14811 . 2 males, BPOT IV #31 , 04.701°S, 36.657°W, 28 May 2004, 38.5 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14818 . 1 male, BPOT IV #12 , 04.881°S, 36.386°W, 26 May 2004, 13.7 m van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14823 . 1 female ovada, BPOT IV #14 , 04.881°S, 36.476°W, 27 May 2004, 47.1 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14805 . 1 manca, BPOT IV #6 , 04.881°S, 36.297°W, 26 May 2004, 17.1 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14821 . 2 male, 4 females, BPOT IV #30 , 04.791°S, 36.656°W, 28 May 2004, 18.8 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14816 . 2 females, BPOT IV #34 , 04.701°S, 36.748°W, 29 May 2004, 24.3 m, van veen, N . Oc . Astro Garoupa coll ., MOUFPE 14812 . 1 female, REVIZEE III # 77A, 01.628°S, 38.166°W, 7 June 1998, 56 m, dredge, NOc Antares coll ., MOUFPE 14841 . 1 female, REVIZEE IV #165, 08.135°S, 34.635°W, 1 December 2000, dredge, NOc Antares coll ., MOUFPE 14838 .

Type locality. Brazil, Ceará State, REVIZEE III #40, 4.084°S, 37.417°W .

Etymology. Named after Manuela Pessoa Fidelis, beloved younger daughter of the second author.

Diagnosis. Body about 2.5 × longer than wide, male pereion 1.6 × length of pleon. Antenna 1 reaching pereonite 1 in the female and pereonite 2 in the male; peduncle article 1 shorter than article 2; article 2 with a tuft of five long setae in the posterodistal angle. Antenna 2 reaching pereonite 5 in the female and pereonite 6 in the male. Pereopod 6 carpus with a distal tuft of long plumose setae. Pleonite 5 posterior margin smooth. Pleopod 2 male appendix almost straight with rounded tip, exceeding the apex of the endopod. Pleopods 4–5 with biarticulate exopod; endopod subequal to the exopod. Uropod exopod with a medial U-shaped excavation ending in an acute process. Pleotelson apex rounded and serrated, with plumose setae.

Description

Holotype. Female, 2.55 mm, MOUFPE 14959. Body about 2.5 × longer than wide; without ornamentation. Head interocular sulcus absent. Pereonite 1 without grooves or ventral carina. Pleonite 1 partially hidden by pereonite 7. Pleonite 2–5 posterolateral angle subacute. Pleonite 5 without dorsal ornamentation.

Antenna 1 reaching 1/3 of pereonite 1; peduncle, article 2 larger than articles 1 and 3, anterodistal angle with a simple seta and a long plumose seta; posterodistal angle with a very long plumose seta, reaching 1/2 of flagellum; article 3, anterodistal angle with a tuft of plumose setae; flagellum longer than peduncle; article 1 1/4 length of article 2; article 2 elongated, larger than article 3 of the peduncle. Antenna 2 reaching pereonite 4. Frontal lamina triangular, with a very narrow basis widening distally. Mandible 3-dentate incisor process; lacinia mobilis present; palp article 2 longer than article 1; article 2 3 × length of article 1, article 3 falciform with plumose setae on inner margin. Maxilla 1, endopod with three plumose robust setae;exopod with eight robust setae. Maxilla 2 medial plate with four simple setae; lateral plate with three simple setae. Maxilliped endite with a marginal robust seta and three distal setae, palp article 2 longer and wider than articles 3 and 4 together.

Pereopod 1 basis narrow; ischium distally enlarged, anterior margin produced over merus; merus anterior and posterior margin slightly produced over carpus, anterodistal margin without setae, posterior margin with three robust setae; carpus short and triangular, with a robust seta and a single long seta; propodus 1.5 × longer than broad, palm with two robust pectinated setae and three setae near the dactylus insertion; dactylus robust without subdistal seta. Pereopod 2 basis narrow; ischium distally enlarged, anterior margin not produced over merus; merus anterodistal margin with three slender setae; short carpal, with 14 robust setae in the posterodistal angle; 3 × longer than broad, palm with two strong marginal setae and two robust setae close to the dactylus insertion; dactylus with a thin subdistal seta. Pereopod 3 similar in form to pereopod 2. Pereopods 4–7 robust, similar in form and increasing gradually in length; basis than 3 × longer than wide or more; ischium, merus, carpal and propodus with robust setae. Pereopod 6 carpus with a distal tuft of very long plumose setae. Pereopod 7 longer than the others.

Pleopod 1 peduncle with four robust setae and a plumose seta on the inner margin. Pleopod 2 peduncle with four robust setae and a plumose seta at the inner margin, pleopod and exopod uniarticulate. Pleopod 3 peduncle with three robust setae and a plumose seta at the inner margin; endopod uniarticulate, subequal to exopod, with plumose setae; exopod biarticulate. Pleopod 4 peduncle with three robust setae and a plumose seta at inner margin; exopod biarticulate. Pleopod 5 peduncle with three robust setae and a plumose seta on inner margin; endopod subequal to exopod and with plumose setae; exopod biarticulate. Uropod peduncle distal internal angle strongly produced and subacute with 2–6 plumose setae; lanceolate endopod, with subacute distal margin; 1.8 × wider than exopod, with short Ushaped medial notch on outer margin, bearing a long plumose seta and three long facial setae; exopod lanceolate, with subacute distal margin. Pleotelson subtriangular, as long as broad, without ridges or dorsal carinae, apex rounded and serrated with plumose setae.

Male (sexually dimorphic characters only)

Body 2.7 × longer than wide, pereion 1.2 × length of pleon. Antenna 1 reaching pereonite 1; antenna 2 reaching pereonite 3.

Distribution. Brazil, Pernambuco, Rio Grande do Norte, Ceará, oceanic banks of the North Chain, 50–56 m depth.

Remarks. Metacirolana manuelae sp. nov. also belongs to the Metacirolana ̍ serrata group̾ and it is similar to Metacirolana menziensi Kensley, 1984 , from Belize, in the absence of any dorsal ornamentation throughout the body and in the shape of the pleotelson. The new species described herein (distinguishing characters of M. menziensi in brackets), however, has a very long sensory seta in article 2 of the peduncle of antenna 1 (vs absent), endopod of the uropod with small U-shaped medial notch at the outer margin, containing a long plumose seta and three long facial setae (vs absent) and pleopods 4–5 exopod biarticulate (vs pleopods 3–5). Metacirolana manuelae sp. nov. is also similar to M. helenae sp. nov. in the format of the endopod of the uropod, but the former has pleonite 1 smooth, the apex of the pleotelson is more rounded and the antennae are shorter. See also Table 2 .

Key to Metacirolana from the Atlantic Ocean

1a. Eyes absent ............................................................................................................................................ 2

2b. Eyes present ........................................................................................................................................... 3

2a Antenna 2 very long, reaching pleonite 3, pereion 1.4 × x longer than pleon; ............... ........................................................................................... Metacirolana mayana ( Bowman, 1987)

2b. Antenna 2 not very long, reaching pereonite 3; pereion 3.6 × x longer than pleon ..... ................................................................................................... Metacirolana caeca ( Hansen, 1916)

3a. Posterior margin of pleonite 5 broadly trilobate .................................................................... 4

3b. Posterior margin of pleonite 5 not broadly trilobate ............................................................ 6

4a. Male antenna 2 reaching pereonite 2, uropod endopod with a medial U-shaped excavation ending in an acute process............... ............... Metacirolana helenae sp. nov.

4b. Male antenna 2 reaching pereonite 4; uropod endopod lacking excavation on outer margin ...................................................................................................................................................... 5

5a. Pleotelson distally triangular, uropod rami strongly dentate .................................................. ........................................................................................... Metacirolana agaricicola Kensley, 1984

5b. Pleotelson distally triangular convex, uropod rami weakly dentate ..................................... ...................................................................................................... Metacirolana agujae Müller, 1991

6a. Body without dorsal spines ............................................................................................................. 7

6b. Body with dorsal spines .................................................................................................................... 8

7a. Antenna 1 article 2 of peduncle with a very long seta, reaching half length of flagellum; pleopods 4–5 exopod biarticulate; uropod endopod with an U-shaped excavation ending in an acute process .......................... Metacirolana manuelae sp. nov.

7b. Antenna 1 article 2 of peduncle lacking a very long seta; pleopods 3–5 exopod biarticulate, uropod endopod without U-shaped excavation ending in an acute process ....................................... ....................................... Metacirolana menziesi Kensley, 1984

8a. Pleotelson tapering to truncate posterior margin ......................... Metacirolana halia Kensley, 1984

8b. Pleotelson tapering to triangular posterior margin ..................................................................... .......................................... Metacirolana riobaldoi ( Lemos de Castro and Brasil Lima, 1976)

Figures

Figure 6. Metacirolana manuelae sp. nov. Holotype, female, 3.2 mm, 4.084°S,37.417°W, MOUFPE 14959. Paratype, male, 4.600°S, 36.883°W, MOUFPE 14843. Scale bars = 0.2 mm. Hb, habitus; f, female; m, male.

Figure 7. Metacirolana manuelae sp. nov. Holotype, female, 3.2 mm, 4.084°S, 37.417°W, MOUFPE 14959. Scale bars = 0.1 mm.A, antenna; Md, mandible; Mx, maxilla; Mxp, maxilliped.

Figure 8. Metacirolana manuelae sp. nov. Holotype, female, 3.2 mm, 4.084°S, 37.417°W, MOUFPE 14959. Scale bars = 0.1 mm. C, clypeus; LF, frontal lamina; P, pereopod.

Figure 9. Metacirolana manuelae sp. nov. Holotype, female, 3.2 mm, 4.084°S, 37.417°W, MOUFPE 14959. Scale bars = 0.1 mm.

Figure 10. Metacirolana manuelae sp. nov. Holotype, female, 3.2 mm, 4.084°S, 37.417°W, MOUFPE 14959. Scale bars = 0.1mm.