Alcolyra, Trivedi & Mitra & Ng, 2022

Trivedi, Jigneshkumar N., Mitra, Santanu & Ng, Peter K. L., 2022, Alcolyra, a new genus of leucosiid crab (Crustacea: Decapoda: Brachyura) from India, Zootaxa 5091 (2), pp. 383-392 : 384-389

publication ID	https://doi.org/ 10.11646/zootaxa.5091.2.9
publication LSID	lsid:zoobank.org:pub:FB74A1EA-B149-48C9-92B7-BD4E519002C0
DOI	https://doi.org/10.5281/zenodo.5847326
persistent identifier	https://treatment.plazi.org/id/0B2C4772-FFAE-FFCB-30A4-FD0BFE0DFF13
treatment provided by	Plazi
scientific name	Alcolyra
status	gen. nov.

Treatment

Genus Alcolyra View in CoL 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 View FIGURE 1 , 2A, B View FIGURE 2 , 3A, D View FIGURE 3 ). 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 View FIGURE 1 , 2A, B View FIGURE 2 , 3A, 3D View FIGURE 3 ). 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 View FIGURE 1 , 2A, B, D View FIGURE 2 , 3A, 3D View FIGURE 3 ). Branchial region with 2 rows of tubercles. Anterolateral, posterolateral and posterior carapace margins granulated ( Figs. 1B View FIGURE 1 , 2B View FIGURE 2 , 3A, 3D View FIGURE 3 ). Posterior carapace margin concave with broadly triangular blunt teeth on lateral sides ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 , 3A, 3D View FIGURE 3 ). Third maxilliped with surfaces granular; ischium longer than wide, longer than merus; exopod elongated, expanded, outer margin convex ( Figs. 1C View FIGURE 1 , 2C View FIGURE 2 , 5B View FIGURE 5 ). Adult cheliped not prominently elongate or swollen; surfaces minutely granular; merus cylindrical, cutting edges of fingers with narrow gape ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ). Ambulatory legs slender, smooth ( Figs. 1F View FIGURE 1 , 2F View FIGURE 2 ). 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 View FIGURE 1 , 2E View FIGURE 2 ). 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 View FIGURE 1 , 2E View FIGURE 2 , 5A View FIGURE 5 ). G1 long, slender, tip with short setae, apical process spatuliform ( Figs. 5C–F View FIGURE 5 ). 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 View FIGURE 3 ).

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 View FIGURE 4 ). 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 View FIGURE 1 , 2B View FIGURE 2 ) and presence of tubercle on either side near the inner lateral margin of somite 5 of sternum of males ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 ).

Alcolyra n. gen. varies from Philyra s. str. in having following characters: carapace suborbicular ( Figs. 1A, B View FIGURE 1 , 2A, B View FIGURE 2 ) (versus pyriform in Philyra s. str., Galil 2009; Fig. 1A View FIGURE 1 ); clear hepatic facet ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 , 6A–C) (versus no clear hepatic facet in Philyra s. str., Galil 2009; Fig. 1A View FIGURE 1 ); branchial regions with two tuberculated rows ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 )(versus branchial region smooth in Philyra s. str., Galil 2009; Fig. 1A View FIGURE 1 ); front with median tooth ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 )(versus no median tooth in Philyra s. str., Galil 2009; Fig. 1A View FIGURE 1 ); surface of cheliped merus minutely granular ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ) (versus with large granules present near proximal margin in Philyra s. str., Galil 2009; Figs. 1A, B View FIGURE 1 ); male thoracic sternite 5 with tubercle on each side of sternopleonal cavity ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 ) (versus tubercle absent in Philyra s. str., Galil 2009; Fig. 1B View FIGURE 1 ); pleonal somites 3–5 fused ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 , 5A View FIGURE 5 ) (versus somites 3–6 fused in Philyra s. str., Galil 2009; Fig. 1B View FIGURE 1 ); male pleonal somite 6 with a proportionately wider proximal margin ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 , 5A View FIGURE 5 ) (versus with margin more narrow in Philyra s. str., Galil 2009; Fig. 1B View FIGURE 1 ); and the G1 apical process is spatuliform ( Fig. 5C–F View FIGURE 5 ) (versus G1 with alate apical process in Philyra s. str., Galil 2009; Fig. 2A View FIGURE 2 ).

Alcolyra n. gen. differs from Afrophila Galil, 2009 in having following characters: carapace suborbicular (versus subovate in Afrophila, Galil 2009 ; Fig. 4A View FIGURE 4 ); branchial regions with two tuberculated rows ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ) (versus branchial region smooth in Afrophila, Galil 2009 ; Fig. 4A View FIGURE 4 ); front with median tooth ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 )(versus no median tooth in Afrophila, Galil 2009 ; Fig. 4A View FIGURE 4 ); adult cheliped merus slender ( Figs. 1B View FIGURE 1 , 2B View FIGURE 2 )(versus swollen in Afrophila, Galil 2009 ; Fig. 4A, B View FIGURE 4 ); male thoracic sternite 5 with tubercle on each side of sternopleonal cavity ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 )(versus no tubercle present in Afrophila, Galil 2009 ; Fig. 4B View FIGURE 4 ); pleonal somites 3–5 narrow ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 , 5A View FIGURE 5 )(versus very broad in Afrophila, Galil 2009 ; Fig. 4B View FIGURE 4 ); and G1 straight with a spatuliform apical process ( Fig. 5C–G View FIGURE 5 )(versus G1 arched distally with rounded apical process in Afrophila, Galil 2009 ; Fig. 2C View FIGURE 2 ).

Alcolyra n. gen. differs from Atlantolocia Galil, 2009 in having following characters: carapace suborbicular ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 ) (versus subpentagonal in Atlantolocia, Galil 2009 ; Fig. 5A View FIGURE 5 ); branchial regions with two tuberculated rows ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 )(versus branchial region smooth in Atlantolocia, Galil 2009 ; Fig. 5A View FIGURE 5 ); front with median tooth ( Figs.1A, B View FIGURE 1 , 2A, B View FIGURE 2 )(versus no median tooth in Atlantolocia, Galil 2009 ; Fig. 5A View FIGURE 5 ); surface of cheliped merus minutely granular ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 )(versus large granules present near proximal margin in Atlantolocia, Galil 2009 ; Fig. 5A, B View FIGURE 5 ); male thoracic sternite 5 with tubercle on each side of sternopleonal cavity ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 )(versus no tubercle present in Atlantolocia, Galil 2009 ; Fig. 5B View FIGURE 5 ); pleonal somites 3–5 fused ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 , 5A View FIGURE 5 )(versus somites 3–6 fused in Atlantolocia, Galil 2009 ; Fig. 5B View FIGURE 5 ); pleonal somite 6 narrow with almost straight lateral margins ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A, C View FIGURE 4 , 5A View FIGURE 5 )(versus very broad with convex lateral margins in Atlantolocia, Galil 2009 ; Fig. 5B View FIGURE 5 ); and the G1 shaft is straight with the apical process spatuliform ( Fig. 5C–F View FIGURE 5 )(versus G1 coiled twice and distally digitate in Atlantolocia, Galil 2009 ; Fig. 2D View FIGURE 2 ).

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 View FIGURE 1 , 2A, B View FIGURE 2 , 3A, D View FIGURE 3 )(versus carapace prominently longer than wide (CL/CW= 1.17–1.26) in Ovilyra, Ng 2021 ; Figs. 1A, B View FIGURE 1 ); the carapace is suborbicular ( Figs. 1A, B View FIGURE 1 , 2A, B View FIGURE 2 , 3A, D View FIGURE 3 )(versus subovate in Ovilyra, Ng 2021 ; Fig. 1A, B View FIGURE 1 ); the carapace surface is distinctly punctate ( Figs. 1A, B View FIGURE 1 , 2A, B View FIGURE 2 , 3A, D View FIGURE 3 )(versus less so in Ovilyra, Ng 2021 ; Fig. 1A, B View FIGURE 1 ); the branchial regions have two tuberculated rows ( Figs. 1A, B View FIGURE 1 , 2A, B View FIGURE 2 , 3A, D View FIGURE 3 )(versus with single granulated row in Ovilyra, Ng 2021 ; Fig. 1A, B View FIGURE 1 ); the lower margin of the hepatic facet lower margin lacks a tooth ( Figs. 1A, B View FIGURE 1 , 2A, B View FIGURE 2 , 3A, D View FIGURE 3 )(versus with broad tooth present on distal one-third in Ovilyra, Ng 2021 ; Fig. 1A, B View FIGURE 1 ); the posterior margin of carapace is concave ( Figs. 1A, B View FIGURE 1 , 2A, B View FIGURE 2 , 3A, D View FIGURE 3 )(versus almost straight in Ovilyra, Ng 2021 ; Fig. 1A, B View FIGURE 1 ); the adult male chelipeds are slender ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 , 3A, D View FIGURE 3 )(versus robust in Ovilyra, Ng 2021 ; Figs. 1A View FIGURE 1 , 2A View FIGURE 2 ); the pollex cutting edge has small teeth of similar sizes ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 , 3A, D View FIGURE 3 )(versus with large subproximal lobe present followed by small teeth of similar sizesin Ovilyra, Ng 2021 ; Fig. 2A View FIGURE 2 ); the thoracic sternum is proportionately much wider ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 )(versus proportionately narrow in Ovilyra, Ng 2021 ; Figs. 1E View FIGURE 1 , 2E View FIGURE 2 ); male thoracic sternite 5 has a prominent tubercle on each side of the sternopleonal cavity ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 )(versus without tubercle in Ovilyra Ng 2021 ; Figs. 1E View FIGURE 1 , 2E View FIGURE 2 ); male pleonal somites 3–5 are fused ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A View FIGURE 4 , 5A View FIGURE 5 )(versus somites 3–6 fused in Ovilyra, Ng 2021 ; Figs. 1E View FIGURE 1 , 2E View FIGURE 2 ); pleonal somite 3 is relatively much wider ( Figs. 1E View FIGURE 1 , 2E View FIGURE 2 , 4A View FIGURE 4 , 5A View FIGURE 5 )(versus only slightly wider in Ovilyra, Ng 2021 ; Figs. 1E View FIGURE 1 , 2E View FIGURE 2 ); and the G1 is slender and straight ( Fig. 5C–F View FIGURE 5 ) (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.