FACETOTECTA GRYGIER, 1985

Chan, Benny K. K., Dreyer, Niklas, Gale, Andy S., Glenner, Henrik, Ewers-Saucedo, Christine, Pérez-Losada, Marcos, Kolbasov, Gregory A., Crandall, Keith A. & Høeg, Jens T., 2021, The evolutionary diversity of barnacles, with an updated classification of fossil and living forms, Zoological Journal of the Linnean Society 193, pp. 789-846 : 822

SUBCLASS FACETOTECTA GRYGIER, 1985

Diagnosis: Dorsal side of naupliar head shield and carapace of y-cyprid with reticulated external cuticular ridges, forming semi-symmetrical patterns of polygonal plates.Knob-shaped dorsocaudal organ on posterior part of naupliar hindbody. Carapace of y-cyprid univalved, partly covers larval body; antennules often with hook on segment 2; labrum unarmed or with 3-5 or more spines; six pairs of biramous swimming thoracopods; abdomen two- or four-segmented; elongated, plated telson with short, unsegmented furcal rami and multiple setae and pore-openings. Slug-like, unsegmented larval stage (ypsigon). Adults unknown.

Comment: Many additional potential species are becoming known as morphological ‘types’ ( Fig. 1A–K ) and are presently also being characterized by molecular methods. A future taxonomy will therefore need new genera and probably also new families ( Grygier et al., 2019).

Hansenocaris Îto, 1985 (12 species)

Figures

Figure 1. Facetotecta. A–F, selected live images of y-nauplii representing some of the morphological diversity: lecitotrophic ones in A, C, D, F; planktotrophic ones in B, E. Note distinct differences in spination and body shapes. G, H, detailed morphology of y-larvae using scanning electron microscopy: G, ventral view; H, dorsal view, showing cuticular facets on the shield. I–K, the drastic metamorphosis from early y-nauplius (I) to last nauplius instar (J) and y-cyprid (K).These three larvae are conspecific.L, higher magnification view of the big rectangular box in K, showing an scanning electron micrograph of the cyprid antennules, with distal hooks (white circles). M, scanning electron micrograph of small square box in K, showing the lateral side of the y-cypris with a spiny labrum. N–P, metamorphosis from y-cypris to free ypsigon. This is most likely to be a larval or juvenile stage of an endoparasitic adult stage in hosts that have yet to be found. The specimens in A, D, F, I–J were sampled in coastal waters in Keelung, Northern Taiwan. The specimens in B, C, E, G, H were sampled on Green Island, Taiwan. The specimens in N–P originate from Sesoko Island, Japan. Abbreviations: a1, antennule; a2, second antennule; ce, compound eye; lb, labrum; mdb, mandible. Specimens J and K provided by Dr. Mark J. Grygier. Specimen J re-photographed from Grygier et al., (2019).