Schizophrys dahlak Griffin and Tranter, 1986

Osman, Marwa M., Sallam, Wafaa S., Madkoura, Fedekar F. & Wicksten, Mary K., 2021, Morphology of camouflage by encrustation in the spider crabs Schizophrys dahlak and Hyastenus hilgendorfi (Decapoda: Brachyura: Majoidea: Epialtidae) from the Suez Canal, Egypt, Journal of Natural History 55 (33 - 34), pp. 2047-2064 : 2051

Schizophrys dahlak Griffin and Tranter, 1986

The carapace of S. dahlak is characterised by two distinguishing features: surface protuberances of different heights and intervals on which clusters of setae are found ( Figure 2 (a)), and patches of denticles with a tusk or tooth shape and a blunt tip. There are three patterns of distribution, with the first pattern being the most common ( Figure 2 (b–d)).

Pattern (1)

Single denticles found in rows, L 1.7 μm and W 0.5 μm. Interval 4 μm, widely distributed on all regions of the exoskeleton ( Figure 2 (b)).

Pattern (2)

Paired denticles found in rows, L 2.7 μm and W 1 μm; interval 6.5 μm, found on left and right branchial regions of carapace ( Figure 2 (c)).

Pattern (3)

Twelve spinules of L 0.3 μm, elliptical in shape, facing the base of a single denticle of L 2.03 μm, interval 3 μm. Commonly distributed on frontal region of carapace and on abdomen ( Figure 2 (d)).

Eight setal types were discovered and photographed on the exoskeleton. No notable difference was seen between males and females or among the size ranges. A description is provided for each setal type observed, including average width and length, presence of outgrowths and their average length, as well as areas of the integument where the setal type was mainly encountered. No pores were present on any of the described forms. All setal forms showed infracuticular articulation (an articulation in the form of a socket, which is drawn into the general cuticle).

Figures

Figure 2. Schizophrys dahlak. (a) Arrows point to surface protuberances among hooked setae. (b–d) Patterns of distribution of the three types of tubercles on S. dahlak integument. (b) Arrow points to single denticles found in rows; (c) paired denticles indicated by arrow; (d) single denticle facing a group of spinules. (e) Arrow indicates typical hooked setae on exoskeleton. (f) Lateral slit present on the proximal portion up to distal end indicated by arrow. Denticles (De) on inside of curve on the distal portion of setal shaft. (g) Simple setae on the branchial and abdominal regions of the exoskeleton. (h) Arrow points to slightly curved distal end of the longest simple setae.