Anthuroidea, Leach, 1814

Jarquín-Martínez, Ubaldo & García-Madrigal, María Del Socorro, 2021, New genus and four new species of anthuroid isopods (Crustacea: Peracarida) from southern Mexican Pacific, Zootaxa 5048 (1), pp. 31-57 : 54-55

Key to species of Anthuroidea from the Mexican Pacific

1 Articles 3–5 of antenna peduncle with sucker-like cuticular structure, antennal flagellum with more than 30 articles ( Fig. 2D )........................................................... Negoescuanthura bastidai n. gen., n. sp. ( Fig. 2A )

- Antenna peduncle articles 3–5 without suck-like cuticular structure, antennal flagellum less than 30 articles............. 2

2(1) Telson with one pair of statocysts......................................................................... 3

- Telson without statocysts.............................................................................. 13

3(2) Pleonites 1–5 fused.................................................................................... 4

- Pleonites 1–3 free, pleonite 4–5 fused............ Amakusanthura guerrerensis Jarquín-Martínez & García-Madrigal, 2021

4(3) Eyes absent; mandibular palp of two articles................................................................ 5

- Eyes present; mandibular palp of three articles.............................................................. 6

5(4) Distal article of mandibular palp with six medial setae and one apical, lacinia with approximately eight denticles…............................................................................. Cortezura penascoensis Schultz, 1977

- Distal article of mandibular palp with three medial setae and one apical, lacinia with approximately 13 denticles............................................................... Cortezura caeca Jarquín-Martínez & García-Madrigal, 2021

6(4) Pereopods 4–7 with carpus more or less triangular, upper margin much shorter than posterior margin................... 7

- Pereopods 4–7 with carpus more or less rectangular, upper margin nearly as long as posterior margin................................................................................ Haliophasma geminata Menzies & Barnard, 1959

7(6) Maxillipedal palp with two free articles.................................................................... 8

- Maxillipedal palp with more than two free articles........................................................... 9

8(7) Distal article of mandibular palp with one apical seta; palm of pereopod 1 without projection....................................................................... Tinggianthura mexicana Jarquín-Martínez & García-Madrigal, 2021

- Distal article of mandibular palp with two apical setae; palm of pereopod 1 projected...... Cyathura munda Menzies, 1951

9(8) Base of mouthparts with medioventral toothlike process. Skuphonura oaxaquensis Jarquín-Martínez & García-Madrigal, 2021

- Base of mouthparts without medioventral toothlike process................................................... 10

10(9) Body densely pigmented.............................................................................. 11

- Body with little pigment............................................................................... 12

11(10) Inner angle of second antennal article strongly projected; palm of pereopod 1 without projection................................................................... Mesanthura antenniformis Jarquín-Martínez & García-Madrigal, 2021

- Inner angle of second antennal article not projected; palm of pereopod 1 staggered............................................................................. Mesanthura estacahuitensis Jarquín-Martínez & García-Madrigal, 2021

12(10) Body with disordered pigment; last article of mandibular palp with row of 10 setae.......................................................................................................... Mesanthura nubifera Wägele, 1984

- Body with circular pigment; last article of mandibular palp with row of five setae.............................................................................................. Mesanthura occidentalis Menzies & Barnard, 1959

13(2) Body with seven large pereonal segments; mandible with palp of 3 articles....................................... 16

- Body with six large pereonal segments; mandible without palp................................................ 14

14(13) Pleonites 1–5 fused with suture lines; pleonite 1 twice as long as pleonite 2...................................... 15

- Pleonites 1–5 fused without suture lines; pleonites of similar lengths.......... Califanthura squamosissima ( Menzies, 1951)

15(14) Pleon longer than pereonites 6+7 and as wide as long; telson 1.3 times as long as pleon and twice as long as wide.................................................................................... Colanthura bruscai Poore, 1984

- Pleon shorter than pereonites 6+7 and 1.2 times width than long ( Fig. 5A, B ); telson 0.9 times as long as pleon and 2.2 times longer than wide ( Fig. 5C ).......................................................... Colanthura gabinae n. sp.

16(13) Pleonites fused; antennule flagellum of three articles; mandibular palp distal article with row of 6–7 robust setae............................................................................. Paranthura californiae Nunomura, 1978

- Pleonites free; antennule flagellum more than three articles; mandibular palp distal article with row more than seven robust setae.............................................................................................. 17

17(16) Pleonites free and articulated........................................................................... 18

- Pleonite 1 free, pleonites 2–5 fused...................................................................... 19

18(17) Distal article of mandibular palp with 14 robust setae; telson ovate................... Paranthura elegans Menzies, 1951

- Distal article of mandibular palp with 16 robust setae; telson rectangular with distolateral margins folder over dorsum….......................................................................... Paranthura longitelson Wägele, 1984

19(17) Body with pigment spots in all somites and telson, pereonites 2–5 of body with central pigment spot ( Fig. 8A ); antennule flagellum of seven articles ( Fig. 8B )..................................................... Paranthura amorensis n. sp.

- Pereonite 4 and 5 with pigment line ( Fig. 11A ); antennule flagellum of five articles ( Fig. 11B )..... Paranthura tientai n. sp.

Figures

FIGURE 2. Negoescuanthura bastidai n. sp., holotype, female, 14.3 mm, UMAR-PERA 566, Estacahuite Beach, Oaxaca. A) Body, dorsal view; B) telson; C) antennula; D) antenna with detail of sucker-like cuticular structures; E) mandible with detail of

FIGURE 5. Colanthura gabinae n. sp., holotype, female, 2.7 mm, UMAR-PERA 572, La Roqueta Island, Guerrero. A) Body, dorsal view; B) pleon; C) telson; D) antennula; E) antenna; F) mandible; G) maxilla; H) maxilliped.

FIGURE 8. Paranthura amorensis n. sp., holotype, female, 5.7 mm, UMAR-PERA 581, Playa del Amor, Zipolite, Oaxaca.A) Body, dorsal view with detail of the telson; B) antennula; C) antenna; D) mandible; E) maxilla; F) maxilliped; G) pereopod 1; H) palm of pereopod 1.

FIGURE 11. P. tientai n. sp., Holotype, female, 7.4 mm, UMAR-PERA 579, El Arrocito Beach, Oaxaca.A) Body, dorsal view and detail of telson; B) antennula; C) antenna with detail of flagellum; D) mandible; E) maxilla; F) maxilliped.