Anthuroidea Leach, 1814

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Suggested Common Name: Wormpods
Number of subordinate taxa: 633 species in 5 families globally, 100 species in all 5 families in our area.
Etymology: after the extralimital Anthura Leach, 1814, which is most likely derived from Ἄνθος [Anthos] = flower [Ancient Greek] referring to the the flower-shaped structure of the uropods and telson. Common name refers to the very elongate worm-like shape of members of this superfamily.
Taxonomic History: Anthuroidea Leach, 1814; Anthurida Monod, 1922
Description: Body elongate-cylindrical; sexual dimorphism moderate to absent, pleopod dimorphism restricted to presence or absence of appendix masculina. Antenna 1 not reduced; scale absent. Antenna 2 scale absent. Mandible incisor cutting, unicuspidate, never multicuspidate; lacinia highly reduced, resembling spines in spine row; molar present, conical, tip obtuse or fitting like a puzzle piece other side, or absent (sometimes absent only on one side; palp present, often secondarily reduced. Maxilla 1 biramous. Maxilla 2 entirely absent. Maxilliped epipod present; basis not dominating to moderately dominating maxilliped size; endite small, triangular, sometimes indistinguishably fused with basis, linking hooks absent; palp present, often secondarily reduced. Pereopods 2-7 coxae formed into coxal plates, variously free to fused with tergites. Penes generally small, often completely flush to sternite. Pleon with all 5 segments free or sometimes with all pleonites fused into one large free pleonite. Pleon all segments free or secondarily fused into one large free pleonite. Pleonite 1 (when free) similar to other pleonites. Pleopod 1 not modified, not sexually dimorphic. Pleopod 2 slightly modified, slightly dimorphic mainly in the presence or absence of the appendix masculina. Pleopod 3 endopod ovate to subrectangular, tip rounded. Telson ventrally flattened, lacking a branchial chamber. Uropods set ventrolaterally on telson; exopod basally folding over telson, creating unique “flower-shaped” shoveling mechanism (simple and peg-shaped in extralimital Leipanthura).
Type taxon: Anthuridae Leach, 1814
Notes: This highly distinct group of burrowing isopods were considered a seperate suborder for a very long time before ultimately being subsumed into Cymothoida. The most important trait of Anthuroidea is the odd "flower-shaped" structure formed from the uropods and telson that functions as a backwards-facing shovel, allowing the animal to burrow both fowards and backwards. The flower structure also seperates this group from other elongate burrowing and intersitial isopods which can be very similar. Oddly enough, the extralimital genus Leipanthura lacks this feature in what is most likely a reversal from the normal character state, as it is otherwise a normal Anthurid. 

Subordinate taxa: Antheluridae, Anthuridae, Expanathuridae, Hyssuridae, Leptanthuridae, Paranthuridae

Key to families
1 a. Mouth pronated into a forward-facing piercing-sucking mechanism; mandible incisor sharply pointing forward, tip acute --> 2
b. Mouth not as above, chewing in arrangement; mandible incisor not as above, compact, tip weakly toothed --> 3

2 (1) a. Antennae 2 flagellum not rudimentary, with 5-10 segments, longer than terminal peduncle segment; statocysts in telson present, paired; pereopod 1 propus palm with an even row of simple or complex marginal setae --> Leptanthuridae
b. Antennae 2 flagellum rudimentary, with less than 5 segments, shorter than terminal peduncle segment; statocysts in telson absent; pereopod 1 propus palm with an irregular row of marginal setae or margin glabrous --> Paranthuridae

3 (1) a. Pereonite 7 longer than wide, about as long as pereonite 6; pleopod 1 resembling other pleopods; pleonites free, as long as wide --> Hyssuridae
b. Pereonite 7 shorter than wide, much shorter than pereonite 6; pleopod 1 weakly or strongly operculiform; pleonites fused or free with at least some wider than long --> 4

4 (3) a. Pleonites fused, often with sutures indicating remnants; telson with paired statocysts; pereopods 4-7 propus with 0-1 posterodistal robust setae, rarely with 1 posterior robust seta; pereopod 7 propus without anterodistal lateral serrate setae --> Anthuridae
b. Pleonites free (rarely fused); telson without statocysts or with 1 medial statocyst; pereopods 4-7 propus with at least 1 posterior robust setae; pereopod 7 propus usually with anterodistal lateral serrate seta(e) --> 5

5 (4) a. Antennae 2 flagellum with over 10 segments; telson with 1 statocyst; maxilliped endite short, broad, palp broad with 5 segments; uropod exopod usually lamellar, lacking dorsal spike --> Antheluridae
b. Antennae 2 flagellum with less than 10 segments; telson without a statocyst; maxilliped endite usually narrow-acute, palp narrow-tapering with (0-)4-5 segments, if only 1 segment than broad; uropod exopod usually lamellar or with strong dorsal spike --> Expandanthuridae

Sources

Brandt, A., & Poore, G. C. (2003). Higher classification of the flabelliferan and related Isopoda based on a reappraisal of relationships. Invertebrate Systematics, 17(6):893-923.

Poore, G. C. (2001). Families and genera of Isopoda Anthuridea. Crustacean Issues, 13:63-173.

Published: Jan 1, 2023