Phylladiorhynchus idas Rodríguez-Flores &amp; Macpherson &amp; Machordom 2021, n. sp.
Creators: name: Rodríguez-Flores, Paula C.
name: Macpherson, Enrique
name: Machordom, Annie
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Galatheidae
Phylladiorhynchus
Phylladiorhynchus idas

description: <i>Phylladiorhynchus idas</i> n. sp. (Fig. 17) <b>Type material.</b> <i>Holotype</i>. French Polynesia. TARASOC Stn DW 3393, 15.8200°S, 148.2800°W, 800 m, 7 October 2009: F 2.5 mm (MNHN-IU-2014-13842). <b>Etymology.</b> From the name <i>Idas</i>, an Argonaut, son of Aphareus and Arene. The name is considered a substantive in apposition. <b>Description.</b> <i>Carapace:</i> Slightly longer than broad; transverse ridges with short setae. Gastric region flattened, with 4 transverse ridges: epigastric ridge indistinct, with 3 spines (1 median and 2 lateral spines) and some outer granules; anterior protogastric ridge medially interrupted, nearly extending laterally to carapace margin; anterior mesogastric ridge medially interrupted, laterally interrupted by anterior branch of cervical groove; anterior metagastric ridge indistinct, with few small scales in the anterior metagastric area. Mid-transverse ridge not interrupted, slightly medially depressed, preceded by shallow or indistinct cervical groove, followed by 2 uninterrupted or minutely interrupted ridges, interspersed with 1 short lateral ridge. Lateral margins slightly convex, with 6 spines: first anterolateral spine well-developed, reaching end of lateral orbital spine, second spine (hepatic) minute but distinct, slightly dorsomesially from lateral margin, and followed by 4 branchial spines (2 anterior spines, first well-developed, followed by a second obsolescent to undistinct spine, and 2 posterior spines). Rostrum triangular, horizontal, dorsally flattish or slightly concave, [1.1] × as long as broad, length [0.3] and breadth [0.3] that of carapace; lateral margins smooth and slightly concave proximally, with well-developed supraocular spines, subapical spines absent. Pterygostomian flap ending in round, upper margin smooth. <i>Thoracic sternum</i>: As wide as long. Sternite 3 broad, [3.0] × as wide as long, anterior margin convex, with a median feeble excavation, moderately produced anterolaterally. Sternite 4 widely contiguous to sternite 3; surface not depressed in midline, smooth; greatest width [2.5] × that of sternite 3, [2.8] × as wide as long. <i>Pleon</i>: Elevated ridges with short setae and with few scattered long setae. Tergite 2 with anterior and posterior transverse elevated ridges; tergites 3 and 4 with anterior transverse ridge; tergites 5–6 smooth. <i>Eye:</i> Eyestalk length about as broad as long, peduncle distally setose, not distinctly expanded proximally; maximum corneal diameter [1.4] × rostrum width, as wide as eyestalk. <i>Antennule</i>:Article 1 more than 1.5 × longer than wide, with 5 spines: distomesial spine well-developed; proximal lateral spine small. <i>Antenna:</i> Article 1 with prominent mesial process, nearly reaching lateralmost antennular spine end. Article 2 with distinct distomesial and distolateral spines. Articles 3 and 4 unarmed. <i>Mxp3:</i> Ischium with distinct distal spines on flexor and extensor margins. Merus [0.7] × length of ischium at middle length, with well-developed distal spine on extensor margin and 2 strong spines on flexor margin (median spine distinctly curved). <i>P1:</i> [3.8] × carapace length; subcylindrical, spiny and with several plumose setae on merus, and carpus and long stiff setae on palm and fingers; merus, carpus and palm with spines along mesial, dorsal and lateral surfaces, distal and mesial spines usually stronger than others. Merus [1.5] length of carapace, [2.4] × as long as carpus. Carpus [3.2] × as long as wide. Palm [1.2] × carpus length, [3.2] × as long as broad. Fingers subequal in length to palm; fixed finger unarmed; movable finger with well-developed basal spine. <i>P2–4:</i> Slender, subcylindrical, moderately setose and spinose. Meri successively shorter posteriorly: P3 merus [0.6] × length of P2 merus, P4 merus [0.9] × length of P3 merus. P2 merus, as long as carapace length, [9.2] × as long as broad, [1.4] × as long as P2 propodus; P3 merus [8.3] × as long as broad, [1.2] × as long as P3 propodus; P4 merus [7] × as long as broad, [1.1] × as long as P4 propodus; extensor margin of P2 and P3 with row of spines, proximally diminishing, with prominent distal spine; P4 extensor margin irregular, with distal spine; flexor margins of P2–4 irregular, each with distal spine; P4 lateral surface with median row of 4 small spines, absent in others. Carpi armed on extensor margin with 1 spine on P2, unarmed on P3–4, distal spine prominent on P2–4. Propodi sharply slender, [10.0–10.1] × as long as broad; extensor margin irregular, usually unarmed; flexor margin with 2–4 slender movable spines in addition to distal pair. Dactyli [0.5] × length of propodus, ending in incurved, strong, sharp spine; flexor margin with 5–6 movable spines. <i>Eggs.</i> No data. <b>Live colour.</b> Unknown. <b>Genetic data.</b> No data. <b>Distribution.</b> French Polynesia, 800 m. <b>Remarks.</b> <i>Phylladiorhynchus idas</i> resembles <i>P. kermadecensis</i> Schnabel &amp; Ahyong, 2019, from New Zealand and <i>P. punctatus</i> from New Caledonia. However, the species can be distinguished by the following characters: - The carapace has 5 epigastric spines in <i>P. kermadecensis</i> and <i>P. punctatus,</i> whereas there are 3 spines and a few granules in <i>P. idas</i>. - The anterior protogastric ridge is not medially interrupted or with a small median gap in <i>P. kermadecensis</i> and <i>P. punctatus,</i> whereas the anterior protogastric ridge is medially interrupted in <i>P. idas</i>. - The anterior metagastric ridge is medially interrupted in <i>P. kermadecensis</i> whereas this ridge is scale-like in <i>P. idas</i>. - Posterior branchial margin with one spine in <i>P. kermadecensis</i>, whereas there are 2 spines in <i>P. idas</i> and <i>P. punctatus</i>. - The extensor margin of the P2–3 propodus is usually armed with 2 proximal spines in <i>P. kermadecensis</i> and <i>P. punctatus</i>, whereas these margins are usually unarmed in <i>P. idas</i>. - The flexor margin of the P2–4 dactyli have 10–11 movable spines in <i>P. kermadecensis</i>, whereas there are 5–6 movable spines in <i>P. idas</i> and 6–7 in <i>P. punctatus</i>.
description: Published as part of <i>Rodríguez-Flores, Paula C., Macpherson, Enrique &amp; Machordom, Annie, 2021, Revision of the squat lobsters of the genus Phylladiorhynchus Baba, 1969 (Crustacea, Decapoda, Galatheidae) with the description of 41 new species, pp. 1-159 in Zootaxa 5008 (1)</i> on pages 48-49, DOI: 10.11646/zootaxa.5008.1.1, http://zenodo.org/record/5157455
description: {"references": ["Schnabel, K. E. &amp; Ahyong, S. T. (2019) The squat lobster genus Phylladiorhynchus Baba, 1969 in New Zealand and eastern Australia, with description of six new species. Zootaxa, 4688 (3), 301 - 347. https: // doi. org / 10.11646 / zootaxa. 4688.3.1"]}