Axiidea, de Saint Laurent, 1979

Poore, Gary C. B., Dworschak, Peter C., Robles, Rafael, Mantelatto, Fernando L. & Felder, Darryl L., 2019, A new classification of Callianassidae and related families (Crustacea: Decapoda: Axiidea) derived from a molecular phylogeny with morphological support, Memoirs of Museum Victoria (Mem. Mus. Vic.) 78, pp. 73-146 : 77-81

Key to families of Axiidea

Figures 2–4

1. Rostrum prominent, often with erect lateral spines, carapace with lateral gastric carinae originating from lateral margins of rostrum, often with submedian and median gastric carinae (figs 2a, b, c); linea thalassinica absent (figs 2e–g); eyestalks cylindrical (figs 2a, b, c) 2

– Rostrum triangular-flat or reduced to short spine shorter than eyestalk, carapace without median and lateral gastric carinae (fig. 2f), or rostrum flat-unornamented, longer than eyestalk, carapace with lateral gastric carinae (fig. 2e); linea thalassinica present over all or part of carapace length (figs 2h–o), or absent, or short; eyestalks contiguous, flat or cylindrical (figs 2d, f, g) 3

2. Rostrum apex bifid, with lateral teeth (fig. 2c); propodi of pereopods 3 and 4 without lateral spiniform setae (fig. 3q); pleopods 3–5 with oblique peduncles meeting mesially, endopods oval, exopods attached laterally, triangular, shorter than endopods, wider proximally than distally (fig. 4p); maxilla scaphognathite with (fig. 3a) or without (fig. 3b) long setae extending from posterior lobe into branchial chamber Strahlaxiidae

–

3. Rostrum with acute or rounded apex (figs 2a, b); propodi of pereopods 3 and 4 with lateral spiniform setae (fig. 3p); pleopods 3–5 with linear peduncles not meeting mesially, endopods linear to elongate-oval, exopods linear-oval, attached subdistally, shorter than or as long as endopod, not overlapping endopods (fig. 4o); maxilla scaphognathite with long setae extending from posterior lobe into branchial chamber (fig. 3a) Axiidae

Maxilla scaphognathite with long setae extending from posterior lobe into branchial chamber (fig. 3a); linea thalassinica complete, partial or absent 4 – Maxilla scaphognathite without long setae extending from posterior lobe into branchial chamber (fig. 3b); linea thalassinica complete over full carapace length (fig. 2h) 5

4. Posterior margin of carapace evenly curved, not interacting with anterolateral lobes on pleomere 1 (fig. 2f); eyestalk flat, contiguous (fig. 2f); chelipeds flattened, asymmetrical (fig. 3j) Callianideidae

– Posterior margin of carapace with lateral lobes interacting with anterolateral lobes on pleomere 1 (fig. 2g); eyestalks cylindrical even if continuous (fig. 2g); chelipeds cylindrical, symmetrical (fig. 3i) Micheleidae 5. Pleomere 1 with dorsal pair of lobes interacting with posterior margin of carapace (fig. 2i); female pleopod 1 with single broad expanded ramus (fig. 4b); pleopod 2 (at least of female) similar to pleopods 3–5 (fig. 4c); epipods present above maxilliped 3 to pereopod 4 Paracalliacidae (1 species, Paracalliax bollorei de Saint Laurent, 1979 ) – Pleomere 1 with evenly curved dorsal margin, not interacting with posterior margin of carapace (fig. 2j); female pleopod 1 with reduced ramus (fig. 4a); pleopod 2 in both sexes (figs 5d–g) smaller than pleopods 3–5 (fig. 5q); epipods absent above maxilliped 3 to pereopod 4 (exception, 2 species of Callianopsidae ) 6

6. Maxilliped 3 dactylus ovate, distally truncate, with dense distal field of setae (fig. 3e) 7

– Maxilliped 3 dactylus linear, with scattered groups of setae (fig. 3f), or densely setose on upper or lower margin (figs 3g, h) 8

7. Uropodal exopod oval, without dorsal plate (fig. 4x); telson parallel-sided over proximal half, then tapering to evenly rounded apex, or widest basally over anterior third, sharp lateral step, then tapering posteriorly to broadly rounded apex; maxilliped 3 propodus longer than wide, not prominently lobed on lower margin (fig. 3e); male pleopod 1 with article 2 triangular, with lobed mesial margin, or flagellate Callianopsidae

– Uropodal exopod with dorsal plate, indicated by secondary row of setae diverging on upper surface from anterior margin (figs 4t, u); telson convex-sided, widest near midpoint, or semicircular, or curving to broad convex apex (figs 4t, u); maxilliped 3 propodus about as wide as long; male pleopod 1 with article 2 linear, or blade like,

with bifid or simple apex, or digitiform (sometimes fused)

Eucalliacidae

8. Uropodal exopod without dorsal plate (fig. 4r), or with distal margin interrupted by weak notch (fig. 4s) 9

Figures

Figure 2. Diagnostic characters for families of Axiidea. Anterior carapace, dorsal: a, Axiidae, Pillsburyaxius; b, Axiidae, Eiconaxius; c, Strahlaxiidae, Neaxius; d, Eucalliacidae, Calliaxina; e, Micheleidae, Tethisea; f, Callianeidae, Callianidea. Carapace, lateral: g, Micheleidae, Michelea; h, Eucalliacidae,Calliaxina. Posterior carapace, pleomeres 1, 2: i, Paracalliacidae;j, Callianassidae.Anterior carapace, branchiostegite, epistome, basal antenna and eyestalk: k, Eucalliacidae, Calliaxina; l, Callichiridae, Callichirus; m, Callichiridae, Lepidophthalmus; n, Callianassidae, Coriollianassa; o, Callianassidae, Biffarius. Original illustrations: i, Paracalliax bollorei, MNHN Th1517; k, Calliaxina sakaii, ULLZ; l, Callichirus islagrande, ULLZ; m, Lepidophthalmus richardi, ULLZ; n, Coriollianassa coriolisae, MNHN-IU-2014-18276; o, Biffarius biformis.

Figure 3. Diagnostic characters for families of Axiidea. Maxilla: a, Axiidae, Eutrichocheles; b, Callianassidae, Arenallianassa. Maxilliped 1: c, Callichiridae; d, Callianassidae. Maxilliped 3: e, Callianopsidae; f, Anacalliacidae; g, Callianassidae, Callianassa; h, Callianassidae, Caviallianassa. Major cheliped: i, Micheleidae, Tethisea; j, Callianideidae, Callianidea; k, Ctenochelidae, Ctenocheles; l, Ctenochelidae, Gourretia; m, Anacalliacidae. Minor cheliped: n, Ctenochelidae, Ctenocheles; o, Ctenochelidae, Gourretia. Pereopod 3, propodus, dactylus: p, Axiidae, Acanthaxius; q, Strahlaxiidae, Neaxius. Pereopod 5, fingers: r, Ctenochelidae, Ctenocheloides; s, Anacalliacidae. The arrows indicate features of interest. Original illustrations: d, Callianassa subterranea, NMV J16779; h, Caviallianassa FP-11, UF 29204.

Figure 4. Diagnostic characters for families of Axiidea. Female pleopod 1: a, Eucalliacidae, Paraglypturus; b, Paracalliacidae. Female pleopod 2: c, Paracalliacidae; d, Eucalliacidae,Calliax; e, Eucalliacidae,Calliaxina; f, Callichiridae; g, Callianassidae.Male pleopod 1: h, i, Callichiridae; j, Callianassidae. Male pleopod 2: k, Ctenochelidae, Ctenocheles; l, Eucalliacidae, Eucalliax; m, Eucalliacidae, Calliaxina; n, Eucalliacidae, Paraglypturus. Pleopod 3: o, Axiidae, Marianaxius; p, Strahlaxiidae, Neaxiopsis; q, Callichiridae. Pleomere 6, uropod, telson: r, Ctenochelidae, Gourretia; s, Ctenochelidae, Paragourretia; t, Eucalliacidae, Calliaxina; u, Eucalliacidae, Eucalliax; v, Callianassidae; w, Anacalliacidae; x, Callianopsidae. Arrows indicate features of interest. Original illustrations: s, Eucalliax quadracuta, NHMW 25916; w, Anacalliax agassizi MNHN Th1206.