Tirmilyra Patel & Naderloo & Trivedi & Mitra 2023, n. gen.

Abstract

<i>Tirmilyra</i> n. gen. <p>(Figs. 1–4)</p> <p> <b>Type species</b>. <i>Philyra sagittifera</i> (Alcock, 1896), by present designation.</p> <p> <b>Species included</b>. <i>Philyra sagittifera</i> (Alcock, 1896) <b>n. comb.</b>, <i>Tirmilyra concinnus</i> (Ghani & Tirmizi, 1995) <b>n. comb.</b></p> <p> <b>Diagnosis.</b> Carapace hexagonal, slightly longer than broad; dorsal surface with regions relatively distinct; gastric, cardiac, branchial, intestinal regions elevated, granules or tubercles arranged in form of three broad ridges, uniting on gastric region forming "arrow" pointing forward (Fig. 1A, B, D, E); median ridge extending from progastric region to intestinal region, lateral ridges extending downwards parallel to anterolateral margins, merging with postero-lateral margins; metagastric region with or without tubercle (Fig. 1A, B, D, E); front straight or bilobed, epistome projecting beyond edge of front; hepatic region excavated, forming depression; upper, lower margins beaded, originating from mid anterolateral margin, not merging anteriorly; broadly triangular tooth projecting on anterior half of lower border of anterolateral margin (Fig. 1A, B, D, E); anterolateral, posterolateral, posterior margins beaded; anterolateral margins merging with posterolateral margin to form broad triangular tooth (Fig. 1A, B, D, E); posterior margin straight to slightly convex, with or without small median tooth in males (Figs. 1A, B, D, E), absent in females (Fig. 2A, C), pointed or blunt dorsoventrally flattened teeth on lateral sides of posterior margin (Figs. 1A, B, D, E; 2A, C). Maxilliped 3 smooth, merus notched; ischium longer than wide, longer than merus; exopod slender, elongated, outer margin convex, setate (Fig. 3A, C). Chelipeds equal; merus, carpus granulated; merus triquetral in cross-section with edges raised and granular; cutting edges of fingers toothed with sparse setae (Figs. 1A, D–F; 2A, C). P2–P5 slender; glabrous (Figs. 1A, D–F, 2A, C). Male pleon with three articulating somites, smooth; somite 1 narrow; somites 2–6 fused, immovable. Telson elongated, apex rounded (Fig. 1C, E; 3B, D). Female pleon ovate; somite 1 free; somites 2–6 fused, suture clearly visible between somites 2 and 3, partial suture visible between somites 3–4 and 5–6. Telson longer than wide, with curved apex (Fig. 2B, D).</p> <p>G1 long, slender, apical process slender, elongated, curved with tapering or spatulate tip, apical lobe setose (Fig. 4A–F). Female gonopore (Fig. 5A, C) on inner anterior edge of sternite 5, oval in shape.</p> <p> <b>Etymology.</b> The new genus is named in honour of late Professor Nasima M. Tirmizi of the University of Karachi, Pakistan, for her valuable contribution to taxonomic studies on brachyuran crabs of the Indian Ocean; used in arbitrary combination with the genus name <i>Philyra</i>. Gender: feminine</p> <p> <b>Remarks.</b> Galil (2009), in her revision of <i>Philyra</i> Leach, 1817, separated the genus into two groups. The first group with the first two male pleonites free (<i>Philyra</i> sensu stricto, <i>Afrophila</i> Galil, 2009, <i>Atlantolocia</i> Galil, 2009, <i>Ryphila</i> Galil, 2009, <i>Ovilyra</i> Ng, 2021, <i>Alocolyra</i> Trivedi, Mitra & Ng, 2022) and second group with the first two somites articulated (<i>Atlantophila</i> Galil, 2009, <i>Lyphira</i> Galil, 2009, <i>Pyrhila</i> Galil, 2009, <i>Hiplyra</i> Galil, 2009). In this regard, <i>Tirmilyra</i> <b>n. gen.</b> belongs to the second group of genera. However, <i>Tirmilyra</i> <b>n. gen.</b> can be immediately distinguished from other genera of second group on the basis of following characteristics: hexagonal carapace, carapace without punctae and bearing three broad tuberculated ridges uniting to form a "broad-arrow" pointing forwards and the male G1 straight, slender, with apical process curved with or without spatulated end. The morphological comparison between <i>Tirmilyra</i> <b>n. gen.</b> and closely related genera is given in Table 1.</p>Published as part of <i>Patel, Krupal, Naderloo, Reza, Trivedi, Jigneshkumar & Mitra, Santanu, 2023, On the taxonomy of Philyra sagittifera (Alcock, 1896) and P. concinnus Ghani & Tirmizi, 1995 (Decapoda, Brachyura, Leucosiidae), with description of a new genus from the Indian Ocean, pp. 430-440 in Zootaxa 5330 (3)</i> on pages 431-434, DOI: 10.11646/zootaxa.5330.3.6, <a href="http://zenodo.org/record/8254906">http://zenodo.org/record/8254906</a&gt