Mykescola Meij, 2025, gen. nov.
Creators: name: Van Der Meij, Sancia E. T.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Cryptochiridae
Mykescola

description: Mykescola gen. nov.
urn:lsid:zoobank.org:act: 97226C86-B3D6-422D-A6F4-BF424131BF2B
Type species. Fungicola syzygia van der Meij, 2015 [by present designation]
Diagnosis. Carapace subrectangular, rounded anteriorly, longer than broad, widest anterior to mid length, flat in lateral view, not deflected anteriorly (Fig. 1B). Carapace surface even, covered with fine granules, mesogastric region slightly inflated, branchial regions separated from mid-gastric and cardio-intestinal regions by shallow furrows. Frontal margin with spinules, sharp internal orbital angle, falling much shorter than external orbital angle. Anterolateral margins with small spinules, few setae, lateral borders slightly concave (Fig. 1B). Pterygostomial region fused to carapace. Ocular peduncles granulated on distal margin, cornea round to oval. Antennal segment longer than broad, extending beyond eyestalk, distal margin with several lateral spines. Antennule same length as ocular peduncles. MXP3 with sub rectangular exopod, merus with distolateral projection, mesial margin finely granulated, with setae. Ventral thorax longer than broad, flat. Chelipeds slender, cutting edges entire; merus as well as upper borders of carpus, palm covered with fine granules. Upper margin of P2-4 coxae granulated, with small forward protruding lobes. P5 slender, mostly smooth. Male abdomen broadly rhomboid.
Colouration. Colour of carapace is a dull beige-grey (often with a horse-shoe shaped off-white pattern), pereiopods semi-translucent (Fig. 2B, D).
Etymology. From the Greek mykes, meaning fungi, and cola, meaning to inhabit, as a nod to the genus Fungicola and in reference to the association of these gall crabs with Fungiidae corals. Gender is masculine.
Comparison with Fungicola. Fungicola and Mykescola gen. nov. are similar in gross morphology. Both genera possess rectanguloid, strongly flattened carapaces, which likely serve as an adaptation to the narrow, slit-like dwellings they inhabit in between the septae of their Fungiidae hosts. Both genera can, however, easily be separated based on the overall shape and evenness of the carapace, frontal margin and shape of the inner orbital angles, and the striking differences in colour pattern (Fig 1, Table 1). There is no doubt about the validity of the three species discussed in this work (F. utinomi, M. fagei comb. nov., M. syzygia comb. nov.), full species descriptions are provided by Fize & Serène (1957) and Van der Meij (2015).
According to the sequence data (cytochrome oxidase subunit 1—COI mtDNA, 16S ribosomal RNA—16S rRNA, Histone H3 nDNA) used to construct the phylogenetic tree in Van der Meij (2015), Fungicola and Mykescola gen. nov. can be distinguished by fixed nucleotide differences across all three markers. Specifically, 45 out of 658 base pairs in COI, 37 out of 599 base pairs in 16S, and 8 out of 266 base pairs in Histone H3 are genus-specific. Detailed nucleotide position diagnostics for Fungicola relative to Mykescola gen. nov. are provided in Table S1. For completeness, the fixed nucleotide differences between M. fagei comb. nov. and M. syzygia comb. nov. species are also provided in this overview, with single nucleotide variations excluded. The genetic divergence, measured as p-distance and expressed as a percentage, between Fungicola and Mykescola gen. nov. at the COI gene is 11.7% (recalculated from Van der Meij 2015).
Lastly, Bähr et al. (2025), in a study on the evolution of fluorescence in Cryptochiridae, showed that fluorescence is not present in Fungicola, while it is present in Mykescola gen. nov., highlighting the potential usefulness of this character as a taxonomic trait.
Coral hosts. Mykescola gen. nov. can be found inhabiting flattened pits lodged between septae of Fungiidae corals. Mykescola fagei comb. nov. predominantly associates with Podabacia and Sandalolitha corals, whereas Mykescola syzygia comb. nov. mainly inhabits Cycloseris and Pleuractis corals (Van der Meij et al. 2015). Fungicola utinomi inhabits a range of hosts but has been found most often in Lithophyllon repanda (Van der Meij 2015; Van der Meij et al. 2015). These host associations, along with the close relationship between Mykescola gen. nov. and Dacryomaia, and their more distant relationship to Fungicola, suggest that multiple host-switching events have taken place between Cryptochiridae and Fungiidae. The genus Fungicola independently host-switched to Fungiidae, just like the clade with Mykescola gen. nov. and Dacryomaia. Noteworthily, Dacryomaia crabs also inhabit corals belonging to the families Leptastreidae and Psammocoridae, coral families that are closely related to the Fungiidae (Kropp 1990; Van der Meij et al. 2015; Quek et al. 2023).
Parasites. A non-ovigerous Mykescola syzygia comb. nov. female (RMNH.Crus.D.56481) has been found parasitized by the isopod, Carcinione platypleura Bourdon, 1983 (Van der Meij 2015; Boyko & Van der Meij 2018). So far there are no reports of parasites in the genus Fungicola.
Distribution. Indo-West Pacific (including the Red Sea) (Van der Meij 2015; Bähr et al. 2025).
description: Published as part of Van Der Meij, Sancia E. T., 2025, Mykescola gen. nov., a new genus for two coral-dwelling gall crab species (Decapoda: Cryptochiridae) inhabiting Fungiidae Dana, 1846 corals, pp. 594-600 in Zootaxa 5631 (3) on pages 596-597, DOI: 10.11646/zootaxa.5631.3.12, http://zenodo.org/record/15370809