Phylladiorhynchus zetes 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 zetes

description: <i>Phylladiorhynchus zetes</i> n. sp. (Figs. 50L, 53, 56C) <b>Type material.</b> <i>Holotype.</i> French Polynesia, Marquesas Islands, Nuku Hiva, Ohotea Point, W side of Taiohae Bay, 08.9309°S, 140.0978°W, 36 m, 28 November 2012: M parasitized 2.1 mm (UF30059). <i>Paratypes</i>: French Polynesia. Marquesas Islands. PAKAIHI I TE MOANA Stn MQ 2-GR-B, 08.9371°S, 140.1206°W, 20–23 m, 7 January 2012: 4 M 1.2–1.6 mm, 1 ov. F 2.3 mm, 3 F 1.2–1.7 mm (MNHN-IU-2019- 2639). <b>Other material</b>. French Polynesia. Marquesas Islands. PAKAIHI I TE MOANA Stn MQ 11-GRS, 10.0140°S, 139. 10°00.845’S, 139°07.345’W 1224°W, 6–12 m, 15 January 2012: 1 F 1.7 mm (MNHN- IU-2019-2602).— Stn MQ 15-GR-B, 10.4718°S, 138.6780°W, 0–28 m, 17 June 2012: 2 M 2.0– 2.2 mm (MNHN-IU-2019-2593).— Stn MQ 19-B, 09.7612°S, 138.8449°W, 10–25 m, 21 January 2012: 2 M 1.8–2.3 mm (MNHN-IU-2019-2600).— Stn MQ 27-GR-B, 08.6781°S, 140.6205°W, 5–22 m, 25 January 2012: 1 M 1.5 mm (MNHN-IU-2019-2589). French Polynesia. BENTHAUS Stn DW1926, 24.6360°S, 146.0136°W, 50–90 m 13 November 2002: 1 F parasitized 2.4 mm (MNHN-IU-2014-13873).— Society Islands. Moorea Islands. 17.5044°S, 149.7584°W, 65–66 m, 26 January 2012: 1 M 1.5 mm (UF33537).— 17.5044°S, 149.7584°W, 65–66 m, 26 January 2012: ov. F 1.4 mm (UF33536).— 17.5526°S, 149.7735°W, 57 m, 27 January 2012: 1 M 1.5 mm (UF33636). French Polynesia. Marquesas Islands. MUSORSTOM 9 Stn DW 1203,09.8783°S, 139.0366°W, 60 m, 28August 1997: 1 M 1.8 mm (MNHN-IU-2014-13874).— Stn CP 1264, 09.3550°S, 140.1283°W, 53–57 m, 03 September 1997: 1 M 2.6 mm (MNHN-IU-2019-2640). <b>Etymology.</b> From the name <i>Zetes</i>, an Argonaut, son of Boreas and Oreithyia. The name is considered a substantive in apposition. <b>Description.</b> <i>Carapace</i>: As long as or slightly wider than long; transverse ridges with dense short setae and few long and thick iridescent setae. Gastric region slightly convex with 4 transverse ridges: epigastric ridge indistinct with 2 median spines and some, and several lateral short scales; anterior protogastric ridge not medially interrupted, nearly extending laterally to carapace margin; anterior mesogastric ridge not medially interrupted, laterally continuing to first branchial spine; anterior metagastric scale-like, often followed by small scale. Midtransverse ridge not interrupted, medially slightly depressed, preceeded by shallow or indistinct cervical groove, followed by 2 not interrupted or laterally interrupted ridges, interspersed with 1 short lateral ridge and few short scales. Lateral margins straight or slightly convex, with 6 distinct spines: first anterolateral spine well-developed, reaching anteriorly to level of lateral orbital spine, second spine (hepatic) small, slightly dorsomesial from lateral margin, and followed by 3–4 branchial spines (3 anterior and 0–1 posterior). Rostrum leaf-like, horizontal, dorsally convex, 1.3–[1.5] × as long as broad, length 0.4 and breadth 0.3 that of carapace; lateral margins minutely serrated and convex, with well-developed supraocular basal spines and subapical spines small. Pterygostomian flap with anterior spine, upper margin smooth. <i>Thoracic sternum</i>: As wide as long. Sternite 3 moderately broad, 1.9–[2.0] × as wide as long, anterior margin convex. Sternite 4 widely contiguous to sternite 3; anterolaterally smooth, surface depressed in midline, smooth; greatest width 2.5–[2.7] × that of sternite 3, [2.7]–2.8 × as wide as long. <i>Pleon</i>: Elevated ridges with short setae and a few scattered long setae. Tergite 2 with anterior and posterior transverse elevated ridges; tergite 3 with anterior transverse ridge, posterior transverse ridge interrupted; tergite 4 with anterior transverse ridge; tergites 5–6 smooth. <i>Eye:</i> Eyestalk length about [1.1] × broader than long, peduncle distally setose, not distinctly expanded proximally, with few short transverse striae on lateral surfaces; cornea expanded distally, maximum corneal diameter 0.7–[1.0] × rostrum width, as wide as eyestalk. <i>Antennule</i>: Article 1 slightly longer than wide, with 5 distal spines: distomesial spine well-developed; proximal lateral spine small, always present. <i>Antenna:</i> Article 1 with prominent mesial process. Article 2 with well-developed distomesial and distolateral spines. Articles 3 and 4 unarmed. <i>Mxp3:</i> Ischium with distinct distal spines on flexor and extensor margins. Merus 0.6–[0.8]× length of ischium, with well-developed distal spine on extensor and flexor margins. <i>P1</i>: [2.6]–3.0 (males), 2.3–2.4 (females) × carapace length; subcylindrical, spiny and with long stiff setae; merus, carpus and palm with spines along mesial, dorsal and lateral surfaces, distal and mesial spines stronger than others. Merus 0.8–[1.0] length of carapace, 1.6–[2.0] × as long as carpus. Carpus [1.7]–2.5 × as long as wide. Palm 1.0–[1.2] × carpus length, [1.8]1.8 × as long as broad. Fingers 0.7–[0.8] × palm length fixed finger with 2 basal spines; movable finger with 1–2 basal spines. <i>P2–4</i>: Stout, setose and spinose. Meri successively shorter posteriorly: P3 merus 0.9–[0.9] × length of P2 merus, P4 merus 0.8–[0.9] × length of P3 merus. P2 merus, 0.6–[0.7] × carapace length, 3.0–[3.5] × as long as broad, 1.1–[1.4] × as long as P2 propodus; P3 merus 3.6–[3.7] × as long as broad, 1.0–[1.3] × as long as P3 propodus; P4 merus 3.5–[3.8] × as long as broad, 0.9–[1.2] × 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, unarmed; flexor margin irregular, with distal spine on P2–4. Carpi with 1–2 spines on extensor margin on P2–3, unarmed on P4; distal spine prominent on P2–3, absent on P4; granules below extensor margin on lateral surface of P2–4; flexor margin unarmed. Propodi stout, [3.5–3.7]3.1–3.9 × as long as broad; extensor margin irregular, armed with 0–3 spines; flexor margin with 3–4 slender movable spines in addition to distal pair. Dactyli 0.6–[0.7] × length of propodi, ending in incurved, strong, sharp spine; flexor margin with 5–6 movable spines. <i>Eggs</i>: Ov. F carried approximately 12– 20 eggs of 0.2–0.3 mm diameter. <b>Live colour.</b> Body light orange, with small orange spots and wittish patches and bands. P1 whitish, palm and fingers orange, distal tip finger darker. P2–4 light whitish-translucent. <b>Genetic data.</b> COI and 16S, Table 1. <b>Distribution.</b> French Polynesia, 20 to 23 m. <b>Remarks.</b> <i>Phylladiorhynchus zetes</i> belongs to the group of species having 2 epigastric spines, 1 hepatic spine, 3 spines on the anterior branchial margin and the pleonal tergite 3 with the posterior ridge interrupted. <i>Phylladiorhynchus zetes</i> closely resembles <i>P. tiphys</i> from New Caledonia but they can be distinguished by the following characters: - One scale with thick setae between the epigastric spines in <i>P. tiphys,</i> whereas this scale is absent in <i>P. zetes</i>. - Thoracic sternite 3 is quadrangular (less than twice as long as wide) in <i>P. tiphys,</i> whereas this sternite is moderately broad (more than twice as long as broad) in <i>P. zetes</i>. - The P2–4 propodi are usually stout in <i>P. zetes</i> (3.1–3.9 × as long as broad), whereas they are more slender in <i>P. tiphys</i> (3.5–4.5 as long as broad). <i>Phylladiorhynchus zetes</i> is also highly similar to <i>P. medea</i>, also found in French Polynesia and New Caledonia. Both species can be distinguished by the following characters: - The rostrum has small or minute subapical spines in <i>P. zetes</i>, whereas these spines are obsolescent in <i>P. medea.</i> - Pleonal tergite 3 has a posterior ridge in <i>P. zetes,</i> whereas this ridge is absent in <i>P. medea</i>. - The P2–4 propodi are usually stout in <i>P. zetes</i> (3.1–3.9 × as long as broad), whereas they are more slender in <i>P. medea</i> (3.5–4.5 as long as broad). The genetic divergences among <i>P. zetes</i>, <i>P. tiphys</i> and <i>P. medea</i> ranged from 7–11% (COI) and 3–6% (16S). The two sequences of <i>P. zetes</i> from French Polynesia diverged by 0.2% (COI) and 0% (16S). The specimens of <i>P. zetes</i> range from 1.2 to 2.6 mm postorbital carapace length.
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 139-144, DOI: 10.11646/zootaxa.5008.1.1, http://zenodo.org/record/5157455