Phylladiorhynchus boucheti 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 boucheti

description: <i>Phylladiorhynchus boucheti</i> n. sp. (Figs. 8, 11I) <b>Type material.</b> <i>Holotype</i>. Chesterfield Islands. KANADEEP Stn DW 4969, 21.0000°S, 158.5000°E, 500–750 m, 8 September 2017: M 2.6 mm (MNHN-IU-2017-3816) <i>Paratypes.</i> Chesterfield Islands. KANADEEP Stn DW 4969, 21.0000°S, 158.5000°E, 500–750 m, 8 September 2017: 1 M 3.0 mm (MNHN-IU-2019-2690).— Stn DW 4993, 4.2500°S, 166.9667°E, 560–610 m, 13 September 2017: 1 ov. F 2.5 mm (MNHN-IU-2017-3830) <b>Etymology</b>. Named after Philippe Bouchet, head of conservation of the general mollusk collection of the Muséum national d’Histoire naturelle, Paris. <b>Description</b>. <i>Carapace</i>: as long as or longer than broad ([1.0]–1.2 × as long as broad); transverse ridges with dense short setae, without long setae. Gastric region flattened, with 3 transverse ridges: epigastric ridge distinct with 4 spines; anterior protogastric ridge not medially interrupted, nearly extending laterally to carapace margin; anterior mesogastric ridge medially interrupted, laterally interrupted by cervical groove; anterior metagastric area with a few scales, otherwise absent. Mid-transverse ridge not interrupted, medially depressed, preceded by distinct cervical groove, followed by 2 not interrupted or minutely interrupted ridges, interspersed with 2 short lateral ridges and few, short scattered scales. Lateral margins straight or slightly convex, with 6–7 spines: first anterolateral spine welldeveloped, overreaching anteriorly level of lateral orbital spine, second spine (hepatic) well-developed, slightly dorsomesially from lateral margin, and followed by 4–5 branchial spines (3 anterior and 1–2 posterior). Rostrum subtriangular, horizontal, dorsally flattish or slightly concave, 0.8–[1.3] × as long as broad, length 0.2–[0.3] and breadth [0.3]0.3 that of carapace; lateral margins smooth and slightly concave, with well-developed supraocular basal spines, and minute subapical spines. Orbit sharply excavated. Pterygostomian flap ending in blunt tooth; upper margin smooth. <i>Thoracic sternum</i>: As wide as long. Sternite 3 sharply broad, [3.5]–4.5 × as wide as long, anterior margin slightly concave, or straight, with median feeble excavation. Sternite 4 widely contiguous to sternite 3; surface depressed in midline, smooth; greatest width 3.0 × that of sternite 3, 2.7–[2.9] × as wide as long. <i>Pleon</i>: Elevated ridges with a few scattered short setae. Tergite 2 with anterior and posterior transverse elevated ridges; tergites 3–4 with anterior transverse ridge; tergites 5–6 smooth. <i>Eye:</i> Eyestalk length as broad as long, peduncle distally setose, not distinctly expanded proximally; maximum corneal diameter 1.0–[1.1] × rostrum width, as wide as eyestalk. <i>Antennule</i>: Article 1 1.5 × longer than wide, with 5 distal spines: distomesial spine well-developed; proximal lateral spine small. <i>Antenna:</i> Article 1 with prominent mesial process, distally clearly not reaching lateralmost antennular spine. Article 2 with minute distal spines laterally and mesially. Articles 3 and 4 unarmed. <i>Mxp3</i>: Ischium with distinct distal spines on flexor and extensor margins. Merus [0.6]–0.7 × length of ischium, with well-developed distal spine on extensor margin and 2 strong spines on flexor margin. <i>P1:</i> [3.9] × carapace length (male), 2.9 (female); subcylindrical, spiny and with scattered long stiff setae; merus, carpus and palm with spines along mesial, dorsal and lateral surfaces, mesial spines usually stronger than others. Merus 1.2–[1.6] length of carapace, [2.1]–2.3 × as long as carpus. Carpus [2.7]–3.5 × as long as wide. Palm 1.1–[1.3] × carpus length, [2.6]–2.7 × as long as broad. Fingers [0.6]–0.8 × palm length; fixed finger unarmed; movable finger with basal spine. <i>P2–4:</i> Slender, subcylindrical, moderately setose and spinose. Meri successively shorter posteriorly: P3 merus 0.7–[0.8] × length of P2 merus, P4 merus 0.8–[0.9] × length of P3 merus. P2 merus, 0.9 × carapace length, [7.2]7.0– 8.5 × as long as broad, [1.3]–1.4 × as long as P2 propodus; P3 merus [6.5]–9.0 × as long as broad, [1.1]–1.3 × as long as P3 propodus; P4 merus [5.4]5.0–7.1 × as long as broad, 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, distal spine absent; flexor margins of P2–3 irregular, with distal spine, absent in P4. Carpi with 1–2 spines on extensor margin on P2–3, distal spine prominent, unarmed on P4; row of small spines below extensor margin on lateral surface of P2–3. Propodi slender, [5.5–7.0]7.1–9.0 × as long as broad; extensor margin irregular, usually armed with distinct spine on proximal half of P2; flexor margin with 4 slender movable spines in addition to distal pair. Dactyli 0.5–[0.6] × length of propodi, ending in incurved, strong, sharp spine; flexor margin with 7–10 movable spines. <i>Eggs</i>: Ov. F (MNHN-IU-2017-3830) carried 25 eggs of 0.3–0.5 mm diameter. <b>Live colour.</b> Unknown. <b>Genetic data.</b> COI, Table 1. <b>Distribution.</b> Chesterfield Islands, from 500 to 750 m. <b>Remarks.</b> <i>Phylladiorhynchus boucheti</i> is characterized by the presence of a triangular rostrum, 4 epigastric spines, 3 spines on the anterior branchial margin of the carapace and Mxp3 merus with 2 spines on the flexor margin. The specimens range from 2.5 to 3.0 mm postorbital carapace length. <i>Phylladiorhynchus boucheti</i> closely resembles to <i>P. iphiclus</i> from French Polynesia and Vanuatu (see the differences under the Remarks of this species).
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 27-29, DOI: 10.11646/zootaxa.5008.1.1, http://zenodo.org/record/5157455