Alcolyra Trivedi & Mitra & Ng 2022, n. gen.
Creators: name: Trivedi, Jigneshkumar N.
name: Mitra, Santanu
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Leucosiidae
Alcolyra

description: Genus Alcolyra n. gen.
Type species. Philyra alcocki Kemp, 1915 by present designation.
Gender of genus. Feminine
Diagnosis. Carapace suborbicular, slightly longer than broad; dorsal surface convex, minutely granulated, covered with scattered punctae, regions relatively distinct; gastric, cardiac, branchial, intestinal regions elevated with patches of granules (Figs. 1A, B, 2A, B, 3A, D). Front anterior margin almost straight with single median tooth projecting beyond visible margin of epistome, epistome and anterior boundaries of pterygostomian regions not projecting beyond the edge of front (1A, B, 2A, B, 3A, 3D). Median ridge faint, undulating posteriorly, running from frontal region posteriorly merging with elevated intestinal region (Figs. 1A, B, 2A, B, 3A, 3D). Hepatic region excavated forming broad shallow depression, upper and lower margins lined with small rounded granules, not merging anteriorly, posteriorly, depression joining anterolateral margin as well-marked obtuse angle (Figs.1A, B, D, 2A, B, D, 3A, 3D). Branchial region with 2 rows of tubercles. Anterolateral, posterolateral and posterior carapace margins granulated (Figs. 1B, 2B, 3A, 3D). Posterior carapace margin concave with broadly triangular blunt teeth on lateral sides (Figs.1A, B, 2A, B, 3A, 3D). Third maxilliped with surfaces granular; ischium longer than wide, longer than merus; exopod elongated, expanded, outer margin convex (Figs. 1C, 2C, 5B). Adult cheliped not prominently elongate or swollen; surfaces minutely granular; merus cylindrical, cutting edges of fingers with narrow gape (Figs. 1A, 2A). Ambulatory legs slender, smooth (Figs. 1F, 2F). Male thoracic sternite 8 visible when pleon closed, between margins of pleonal somites 2 and 3; sternites covered with scattered punctae; outer lateral margin of sternite 4 swollen forming longitudinal ridge on either side in adults; sternite 5 with large tubercle near inner lateral margin on each side of sternopleonal cavity, adjacent to base of first ambulatory leg; sternopleonal cavity deep; reaching to mid distance between fused thoracic sternites 1–3 (Figs. 1E, 2E). Male pleon narrow; somites 1 and 2 free; somite 1 longitudinally narrow; somite 2 yoke-like, reaching coxae of fourth ambulatory leg, somites 3–5 fused, surface with scattered punctae, unarmed; somite 6 longer than broad, free, surface unarmed, base broader than distal end of preceding somite; telson triangular, longer than wide, with rounded apex (Figs. 1E, 2E, 5A). G1 long, slender, tip with short setae, apical process spatuliform (Figs. 5C–F). Female pleon longitudinally ovate, somites 1 and 2 free, somites 3–6 completely fused to form domed plate; vulvae large, obliquely ovate, on anterior part of sternite 6, without sternal vulvar cover (Figs. 3B, E).
Etymology. The genus is named in honour of Alfred William Alcock for his valuable contribution in taxonomy brachyuran crabs of Indian Ocean, in arbitrary combination with the suffix of the genus name Philyra.
Remarks. According to the revision of Philyra Leach, 1817 by Galil (2009), Alcolyra n. gen. falls into the second group of genera in which first two male pleonal somites are free (Figs. 4B, D). This second group contains genera like Philyra s. str., Afrophila Galil, 2009, Atlantolocia Galil, 2009, Ryphila Galil, 2009 and Ovilyra Ng, 2021. However, Alcolyra n. gen. can be distinguished from these genera in having two tuberculated rows on branchial region of carapace (Figs. 1B, 2B) and presence of tubercle on either side near the inner lateral margin of somite 5 of sternum of males (Figs. 1E, 2E).
Alcolyra n. gen. varies from Philyra s. str. in having following characters: carapace suborbicular (Figs. 1A, B, 2A, B) (versus pyriform in Philyra s. str., Galil 2009; Fig. 1A); clear hepatic facet (Figs.1A, B, 2A, B, 6A–C) (versus no clear hepatic facet in Philyra s. str., Galil 2009; Fig. 1A); branchial regions with two tuberculated rows (Figs.1A, B, 2A, B)(versus branchial region smooth in Philyra s. str., Galil 2009; Fig. 1A); front with median tooth (Figs.1A, B, 2A, B)(versus no median tooth in Philyra s. str., Galil 2009; Fig. 1A); surface of cheliped merus minutely granular (Figs. 1A, 2A) (versus with large granules present near proximal margin in Philyra s. str., Galil 2009; Figs. 1A, B); male thoracic sternite 5 with tubercle on each side of sternopleonal cavity (Figs. 1E, 2E) (versus tubercle absent in Philyra s. str., Galil 2009; Fig. 1B); pleonal somites 3–5 fused (Figs. 1E, 2E, 4A, C, 5A) (versus somites 3–6 fused in Philyra s. str., Galil 2009; Fig. 1B); male pleonal somite 6 with a proportionately wider proximal margin (Figs. 1E, 2E, 4A, C, 5A) (versus with margin more narrow in Philyra s. str., Galil 2009; Fig. 1B); and the G1 apical process is spatuliform (Fig. 5C–F) (versus G1 with alate apical process in Philyra s. str., Galil 2009; Fig. 2A).
Alcolyra n. gen. differs from Afrophila Galil, 2009 in having following characters: carapace suborbicular (versus subovate in Afrophila, Galil 2009; Fig. 4A); branchial regions with two tuberculated rows (Figs.1A, B, 2A, B) (versus branchial region smooth in Afrophila, Galil 2009; Fig. 4A); front with median tooth (Figs.1A, B, 2A, B)(versus no median tooth in Afrophila, Galil 2009; Fig. 4A); adult cheliped merus slender (Figs. 1B, 2B)(versus swollen in Afrophila, Galil 2009; Fig. 4A, B); male thoracic sternite 5 with tubercle on each side of sternopleonal cavity (Figs. 1E, 2E)(versus no tubercle present in Afrophila, Galil 2009; Fig. 4B); pleonal somites 3–5 narrow (Figs. 1E, 2E, 4A, C, 5A)(versus very broad in Afrophila, Galil 2009; Fig. 4B); and G1 straight with a spatuliform apical process (Fig. 5C–G)(versus G1 arched distally with rounded apical process in Afrophila, Galil 2009; Fig. 2C).
Alcolyra n. gen. differs from Atlantolocia Galil, 2009 in having following characters: carapace suborbicular (Figs.1A, B, 2A, B) (versus subpentagonal in Atlantolocia, Galil 2009; Fig. 5A); branchial regions with two tuberculated rows (Figs.1A, B, 2A, B)(versus branchial region smooth in Atlantolocia, Galil 2009; Fig. 5A); front with median tooth (Figs.1A, B, 2A, B)(versus no median tooth in Atlantolocia, Galil 2009; Fig. 5A); surface of cheliped merus minutely granular (Figs. 1A, 2A)(versus large granules present near proximal margin in Atlantolocia, Galil 2009; Fig. 5A, B); male thoracic sternite 5 with tubercle on each side of sternopleonal cavity (Figs. 1E, 2E)(versus no tubercle present in Atlantolocia, Galil 2009; Fig. 5B); pleonal somites 3–5 fused (Figs. 1E, 2E, 4A, C, 5A)(versus somites 3–6 fused in Atlantolocia, Galil 2009; Fig. 5B); pleonal somite 6 narrow with almost straight lateral margins (Figs. 1E, 2E, 4A, C, 5A)(versus very broad with convex lateral margins in Atlantolocia, Galil 2009; Fig. 5B); and the G1 shaft is straight with the apical process spatuliform (Fig. 5C–F)(versus G1 coiled twice and distally digitate in Atlantolocia, Galil 2009; Fig. 2D).
Alcolyra n. gen. differs from Ovilyra Ng, 2021 in that the carapace is only slightly longer than wide (CL/ CW= 1.07–1.1) (Figs. 1A, B, 2A, B, 3A, D)(versus carapace prominently longer than wide (CL/CW= 1.17–1.26) in Ovilyra, Ng 2021; Figs. 1A, B); the carapace is suborbicular (Figs. 1A, B, 2A, B, 3A, D)(versus subovate in Ovilyra, Ng 2021; Fig. 1A, B); the carapace surface is distinctly punctate (Figs. 1A, B, 2A, B, 3A, D)(versus less so in Ovilyra, Ng 2021; Fig. 1A, B); the branchial regions have two tuberculated rows (Figs. 1A, B, 2A, B, 3A, D)(versus with single granulated row in Ovilyra, Ng 2021; Fig. 1A, B); the lower margin of the hepatic facet lower margin lacks a tooth (Figs. 1A, B, 2A, B, 3A, D)(versus with broad tooth present on distal one-third in Ovilyra, Ng 2021; Fig. 1A, B); the posterior margin of carapace is concave (Figs. 1A, B, 2A, B, 3A, D)(versus almost straight in Ovilyra, Ng 2021; Fig. 1A, B); the adult male chelipeds are slender (Figs. 1A, 2A, 3A, D)(versus robust in Ovilyra, Ng 2021; Figs. 1A, 2A); the pollex cutting edge has small teeth of similar sizes (Figs. 1A, 2A, 3A, D)(versus with large subproximal lobe present followed by small teeth of similar sizesin Ovilyra, Ng 2021; Fig. 2A); the thoracic sternum is proportionately much wider (Figs. 1E, 2E)(versus proportionately narrow in Ovilyra, Ng 2021; Figs. 1E, 2E); male thoracic sternite 5 has a prominent tubercle on each side of the sternopleonal cavity (Figs. 1E, 2E)(versus without tubercle in Ovilyra Ng 2021; Figs. 1E, 2E); male pleonal somites 3–5 are fused (Figs. 1E, 2E, 4A, 5A)(versus somites 3–6 fused in Ovilyra, Ng 2021; Figs. 1E, 2E); pleonal somite 3 is relatively much wider (Figs. 1E, 2E, 4A, 5A)(versus only slightly wider in Ovilyra, Ng 2021; Figs. 1E, 2E); and the G1 is slender and straight (Fig. 5C–F) (versus distal quarter sharply bent backwards 120–150° from the longitudinal axis in Ovilyra, Ng 2021; Fig. 6A, E).
Of the 27 species of Philyra sensu lato left untreated by Galil (2009), five species were described from India, including P. alcocki. The first author is revising the taxonomy of Philyra sexangula Alcock, 1896 which together with a new species as well as P. nishihirai Takeda & Nakasone, 1991 and P. taekoae Takeda, 1972 from the western Pacific, will be placed in a new genus (Trivedi et al., in review). Philyra sagittifera (Alcock, 1896) will also need to be transferred to a new genus along with P. concinnus Ghani & Tirmizi, 1955 from Pakistan (Trivedi et al., in preparation). The generic positions of two more species, P. corrallicola Alcock, 1896 and P. malefactrix (Kemp, 1915) are now under study.
description: Published as part of Trivedi, Jigneshkumar N., Mitra, Santanu & Ng, Peter K. L., 2022, Alcolyra, a new genus of leucosiid crab (Crustacea: Decapoda: Brachyura) from India, pp. 383-392 in Zootaxa 5091 (2) on pages 384-389, DOI: 10.11646/zootaxa.5091.2.9, http://zenodo.org/record/5843721