Domeciidae Ortmann 1893
Creators: name: Ng, Peter K. L.
name: Ahyong, Shane T.
name: Castro, Peter
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Domeciidae

description: Family Domeciidae Ortmann, 1893   Diagnosis. Carapace transversely hexagonal to almost ovate; antero- and posterolateral margins demarcated, anterolateral margin with 2 or 3 teeth, sometimes low, and additional acute granules or spinules (Fig. 11I–K); front bilobed, lined with sharp granules or short spines; posterolateral margin gently convex to sinuous (Fig. 11I–K); carapace relatively low, dorsal surface gently sinuous; posterior margin of epistome with small median lobe, lateral margin relatively short, gently concave, with triangular lobe just before pterygostomial lobe, separated by V-shaped cleft (Fig. 5E, F). Basal antennal article quadrate, mobile, peduncle entering hiatus of orbit. Maxilliped 3 merus very short, appearing compressed, anteroexternal part not auriculiform, narrower than large trapezoidal ischium; distal edge of exopod reaching to distal edge of merus (Fig. 6F). Chelipeds relatively short, heterochelous, larger cheliped shorter than twice carapace width; merus quadrate in dorsal view, flexor margin smooth or finely granular, extensor margin with sharp spines or tubercles; carpus inner angle with spine or tooth; propodus outer surface with prominent rounded or pointed tubercles (Fig. 11I–K). P2–5 short to very short, longest pereopod slightly longer than carapace width; merus relatively stout (Fig. 11I–K). Sternopleonal cavity reaching anteriorly to level of posterior margin of P2 coxae (Fig. 7H, I); tubercle of male pleonal-locking mechanism distinct, on posterior third of thoracic sternite 5, may be near suture with sternite 6 (Fig. 8L). Male pleon triangular, lateral margins of somites 3–6 converging, all somites and telson free (Figs. 7H, I, 8F). G1 relatively stout, with distal portion slender, straight to curved, distal margins lined with short spinules or setae (Fig. 9O, Q). G2 relatively stout, elongated, more than half to subequal length of G1, distal portion flattened, spatuliform (Fig. 9P, R). Vulvae relatively large, positioned on anterior half of sternite 6, positioned close to median line, opening directed anteriorly with lateral sternal vulvar cover directed anteriorly (Fig. 10H) or opening obliquely inwards (Fig. 10I, J).   
 Genera included. Cherusius Low & Ng, 2012, Domecia Eydoux & Souleyet, 1842, Maldivia Borradaile, 1902, and Palmyria Galil & Takeda, 1986.   
 Remarks. Rathbun (in Edmondson, 1923) described two new species from Palmyra Island in the central Pacific, the domeciid Maldivia palmyrensis (presently in Palmyria Galil & Takeda, 1986) and the portunid Charybdis (Charybdis) cookei. The description was part of a larger article by Edmondson (1923) on the Crustacea from Palmyra and the Fanning Islands. The format of this publication is such that the taxa could be cited as Rathbun (1923) or Rathbun (in Edmondson, 1923). The article is the only one included in a volume of the P. Bishop Museum Bulletin, and the title on the cover page: “Crustacea from Palmyra and Fanning Islands by Charles Howard Edmondson with descriptions of new species of crabs from Palmyra Island by Mary J. Rathbun” leaves no doubt of Rathbun’s contribution. The main text and the treatment of all the previously described taxa were by Edmondson (1923: 1–37). In his introduction, Edmondson (1923: 7) stated: “In addition to previous acknowledgments, credit is due Drs. Mary J. Rathbun and Waldo L. Schmitt of the United States National Museum for services rendered in the identification of certain species included in this paper. Rathbun also described two new species of crabs from Palmyra Island. (See p. 38).” There is a new heading on page 38 that reads: “Descriptions of new species of crabs from Palmyra Island by Mary J. Rathbun”, and the two new species were described in the next two pages (Edmondson, 1923: 38–40). After Rathbun’s section, Edmondson (1923: 41–43) provided an index followed by the plates. One of the authors (PC) checked both the original “Bulletin of the Bernice P. Bishop Museum” as well as the reprint, and the information is identical. Placed in the complete context, the best way to cite authorship of the two species is “Rathbun in Edmondson, 1923 ”.   
 All domeciids are symbionts of zooxanthellate (hermatypic) scleractininan corals and, less commonly, hydrozoans and sponges (Castro, 2015; van der Meij et al., 2022). Phylogenetic relationships of Domecia and its mitochondrial genome were analysed by van der Meij et al. (2022) and Bravo et al. (2023), respectively.
description: Published as part of Ng, Peter K. L., Ahyong, Shane T. & Castro, Peter, 2023, Re-appraisal of the families and subfamilies of Trapezioidea Miers, 1886, with establishment of a new family, Ectaesthesiidae (Crustacea: Decapoda: Brachyura), pp. 606-631 in Raffles Bulletin of Zoology 71 on pages 624-626, DOI: 10.26107/RBZ-2023-0047, http://zenodo.org/record/10271307