Phylladiorhynchus integrus ( Benedict, 1902 )

Rodríguez-Flores, Paula C., Macpherson, Enrique & Machordom, Annie, 2021, Revision of the squat lobsters of the genus Phylladiorhynchus Baba, 1969 (Crustacea, Decapoda, Galatheidae) with the description of 41 new species, Zootaxa 5008 (1), pp. 1-159 : 54-58

Phylladiorhynchus integrus ( Benedict, 1902)

( Figs. 18 , 19 , 21F )

Galathea integra Benedict, 1902: 248 (type locality: off Honshu, Japan, 110–128 m [syntypes, USNM 26168]).— Balss, 1913: 7, fig. 4 ( Japan, 110-180 m).—Yokoya, 1933: 55 ( Japan, off Shiwoya, S of Inuboe-zaki, E coast of Aomori Pref., Sagami Bay, Suruga Bay, E of Omaezaki, N of Tanegashima, E of Kagoshima, N of Goto I. N of Noto, N of Oga W of Aomori Pref. W of Tsugaru Strait, Tsugaru Strait, 71–307 m).— Makarov, 1938: 88, fig. 31 (no record).—Miyake, in Miyake & Nakazawa, 1947: 732, fig. 2117 (no record).

Records requiring verification:

Galathea integra .— Laurie, 1926: 135 (Providence, 106 m). Phylladiorhynchus ikedai . — Baba, 2005: 200, 304. Phylladiorhynchus pusillus .—Miyake, 1965: 635, fig. 1044 (no record).— Miyake & Baba, 1967: 234, fig. 6 (East China Sea,

102–196 m).— Baba et al., 2009: 287, fig. 263, 264 ( Taiwan 115–1261 m).— Lee et al., 2019: 730, figs. 3, 4 (South of Jeju

Is., Korea, 150 m).

Type material. Lectotype. Japan. Honshu , 110–128 m, ov. F 3.6 mm ( USNM 26168 ).

Paralectotypes. station data as lectotype, 17 M 3.0– 4.8 mm, 11 ov. F 2.8–3.7 mm ( USNM 26168 ) .

Other material. Taiwan.Aodi, Taipei County. Stn CP 58, 24.5850°N, 122.0966°E, 221–254 m, 4August 2000: 3 M 2.7–3.2 mm, 1 ov. F 3.5 mm ( NTOU) .— Stn CP76, 24.9423°N, 122.0251°E, 115–170 m, 7 May 2001: 1 F 1.8 mm ( NTOU) .— Stn CP85, 24.0092°N, 122.0090°E, 255–390 m, 9 May 2001: 6 M 2.2–4.0 mm ( NTOU) .— Stn DW149, 22.3083°N, 121.4895°E, 258 m, 20 May 2002: 1 M 2.0 mm ( NTOU) .— Stn CP277, 24.3928°N, 122.2353°E, 1222– 1261 m, 14 June 2005: 1 M 3.8 mm ( NTOU) .— Stn OCP287, 24.9587°N, 122.0884°E, 259–349 m, 8 August 2005: 11 M 2.1–2.6 mm, 1 ov. F 2.6 mm, 8 F 1.5–2.7 mm ( NTOU) .— Stn OCP288, 24.9617°N, 122.0891°E, 263–352 m, 8 August 2005: 27 M 1.1–4.2 mm, 2 ov. F 2.4– 2.6 mm, 13 F 2.1–3.0 mm ( NTOU) .— Stn OCP 293, 24.9728°N, 122.0882°E, 262– 232 m, 8 August 2005: 28 M 1.5–3.4 mm, 3 ov. F 2.4–2.7 mm, 25 F 1.4–3.4 mm ( NTOU) .

Indonesia. KARUBAR Stn CP 05, 05.8167°S, 132.3000°E, 296–299 m, 22 October 1991: 1 F 3.1 mm (MNHN- IU-2016-9659).— Stn DW 13, 05.4333°S, 132.6333°E, 417–425 m, 24 October 1991: 1 F 4.8 mm (MNHN-IU-2014- 13804), 1 F broken (MNHN-IU-2014-13854).— Stn CP 16, 05.2833°S, 132.8333°E, 315–349 m, 24 October 1991: 1 M 4.2 mm (MNHN-IU-2014-13852), 1 ov. F 3.5 mm (MNHN-IU-2016-426).— Stn CP 25, 05.5000°S, 132.8667°E, 336–346 m, 26 October 1991: 1 F 2.9 mm (MNHN-IU-2014-13856).— Stn CP 36, 06.0833°S, 132.7333°E, 210–268 m, 27 October 1991: 1 ov. F 3.2 mm (MNHN-IU-2014-13853) .

Chesterfield Islands . EBISCO Stn DW 2603, 19.6294°’S, 158.7316°E, 568–570 m, 18 October 2005: 1 ov. F 4.1 mm (MNHN-IU-2014-13855).— Stn DW 2603, 19.6294°S, 158.7316°E, 568–570 m, 18 October 2005: 1 ov. F 3.5 mm (MNHN-IU-2016-425).—KANADEEP Stn DW 4975, 19.7500°S, 158.5833°E, 386–428 m, 9 September 2017: 1 ov. F 3.3 mm (MNHN-IU-2017-2432) .

Description. Carapace: as long as or slightly broader than long; transverse ridges with dense short setae and few scattered long thick iridescent setae. Gastric region slightly convex, with some transverse ridges: epigastric ridge distinct usually armed with 4 epigastric spines, inner pair longer, often a median scale with thick or plumose setae anterior to epigastric ridge; anterior protogastric ridge not medially interrupted, nearly extending laterally to carapace margin; anterior mesogastric ridge not medially interrupted, laterally interrupted by cervical groove, laterally continuing to first branchial spine; anterior metagastric ridge not medially interrupted, laterally interrupted; posterior epigastric, protogatric, mesogastric, and metagastric ridges scale-like. Mid-transverse ridge uninterrupted, medially slightly depressed, preceded by shallow or indistinct cervical groove, followed by 3 uninterrupted or minutely interrupted ridges, interspersed with 2 short lateral ridge and sometimes few, short scattered scales. Lateral margins slightly convex, with 7–8 spines: first anterolateral spine well-developed, reaching anteriorly to level of lateral orbital spine, second spine (hepatic) well-developed, slightly dorsomesially from lateral margin, and followed by 5–6 branchial spines (3 anterior and 2–3 posterior). Rostrum leaf-like, horizontal, dorsally flattish or slightly concave, [1.6]–1.9 × as long as broad, length [0.4]–0.5 and breadth 0.2–[0.3] that of carapace; lateral margins smooth and convex, with well-developed supraocular basal spines and small subapical spines. Pterygostomian flap ending in blunt tooth, upper margin smooth.

Thoracic sternum: As wide as long. Sternite 3 moderately broad, [2.0]–2.5 × as wide as long, anterior margin with obtuse median projection. Sternite 4 widely contiguous to sternite 3; surface depressed in midline, smooth; greatest width 2.5–[3.4] × that of sternite 3, 2.6–[2.8] × as wide as long.

Pleon: Elevated ridges with dense short setae and scattered long setae. Tergites 2–3 with anterior and posterior transverse elevated ridges; tergite 4 with anterior transverse ridge; tergites 5–6 smooth.

Eye: Eyestalk length about 0.9 × broader than long, peduncle distally setose, not distinctly expanded proximally, with few short transverse striae on lateral surfaces; maximum corneal diameter 1.2 × rostrum width, as wide as eyestalk (0.95 × maximum peduncle width).

Antennule: Article 1 1.3 × longer than wide, with 4 well-developed distal spines: distomesial spine welldeveloped; proximal lateral spine usually absent, minute if present.

Antenna: Article 1 with prominent mesial process, distally falling short of lateral antennular spine. Article 2 with minute distomesial spine, distolateral spine larger than distomesial. Article 3 with minute or obsolescent distal mesial spine. Article 4 unarmed.

Mxp3: 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 and flexor margins.

P1 (lost in lectotype): 3.1(males), 2.9–3.3 (females) × carapace length; subcylindrical, spiny and with scattered long stiff setae; merus, carpus and palm with spines along mesial, dorsal and lateral surfaces, distal and mesial spines usually stronger than others. Merus 1.1–1.7 length of carapace, 2.1–3.2 × as long as carpus. Carpus 1.5–2.7 × as long as wide. Palm1.2 × carpus length, 1.7–2.5 × as long as broad. Fingers 0.8–0.9 × palm length; fixed finger lateral margin unarmed; movable finger with small to well-developed basal spine.

P2–4 (P 2 in lectotype only): Slender, subcylindrical, moderately setose and spinose. Meri successively shorter posteriorly: P3 merus 0.4–0.6 × length of P2 merus, P4 merus 0.8 × length of P3 merus. P2 merus, 0.6–[0.9] × carapace length, [4.8]–6.5 × as long as broad, 1.2–1.3 × as long as P2 propodus; P3 merus 4.8–6.3 × as long as broad,1.1–1.2 × as long as P3 propodus; P4 merus 4.4 × 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 present; flexor margin irregular, with distal spine on P2–3, absent in P4; P2–3 lateral surface unarmed. Carpi with 2–6 spines on extensor margin on P2–3, unarmed on P4; distal spine prominent on P2–3, smaller or absent on P4; row granules below extensor margin on lateral surface of P2–4; flexor margin unarmed. Propodi moderately slender, 5.0–6.4 × as long as broad; extensor margin irregular usually armed proximally with 3 small spines on P2–3; flexor margin with 3–4 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 6–8 movable spines.

Eggs. Ov. F carried approximately 30– 50 eggs of 0.4–0.5 mm diameter.

Live colour. Carapace and pleon translucent white or diffuse orange red; carapace lateral spines and rostral supraocular basal spines orange red. P1 diffuse orange-red. P2–4 with diffuse, clear orange-red bandings (after Baba et al. 2009).

Genetic data. COI and 16S, Table 1.

Distribution. Japan, Korea, Taiwan, Indonesia, Chesterfield Islands, from 110 to 1261 m.

Remarks. Phylladiorhynchus integrus was described as Galathea integra by Benedict (1902) from specimens collected in Honshu, Japan. The species was previously collected in other Japanese localities (as G. integra ) and from Taiwan, Korea and Eastern China Sea (as P. pusillus ) (see above). The examination of the type specimens of the species indicates that it is a valid species, widely distributed in the western Pacific, and differentiated from other species of Phylladiorhynchus by several constant morphological differences. Phylladiorhynchus integrus belongs to the group of the species having 4 spines on the epigastric ridge, 1 well-developed hepatic spine, the anterior metagastric ridge not medially interrupted, the anterior margin of thoracic sternite 3 medially projected and a single spine on the flexor margin of Mxp3 merus. The species closely resembles P. australis Schnabel & Ahyong, 2019 and P. nui Schnabel & Ahyong, 2019 from Eastern Australia and New Zealand. However, the three species can be distinguished among them by the following characters:

- The rostrum lateral margin is straight in P. nui , whereas it is convex in P. australis and P. integrus .

- The lateral-most spine of antennular article 1 is very small to indistinct in P. nui and P. integrus , whereas this spine is always distinct in P. australis . and 4. D, left cephalic region, showing antennular and antennal peduncles, ventral view. E, right Mxp3, lateral view. F, right P2, lateral view. Scale bar: A, E–H = 1.0 mm; B–D, I = 0.6 mm.

- The antennal article 2 is armed with a well-developed distolateral spine, reaching or overreaching the end of article 3 in P. australis , whereas this spine is minute or obsolescent in P. nui and P. integrus .

- The P2–4 propodi are more slender in P. nui (6 × as long as broad) than in P. australis and P. integrus (5 × as long as broad).

- The flexor margin of the P2–4 dactyli has 9–11 movable spines in P. nui , having 6–9 spines in P. australis and P. integrus .

The specimens of P. integrus range from 1.4 to 4.8 mm postorbital carapace length. Phylladiorhynchus integrus diverged 12–13% (COI) and 5–6% (16S) from P. nui and P. australis , respectively. The four and three sequences of P. integrus from Indonesia, New Caledonia and Taiwan diverged 0.3–4.7% for COI and 0–0-8% for 16S respectively.

Figures

FIGURE 18. Phylladiorhynchus integrus (Benedict, 1902), A, C-F, lectotype ovigerous female 3.6 mm (USNM26188); B, paralectotype male 3.0 mm (USNM26168): A, carapace and pleon, dorsal view. B, rostrum, dorsal view. C, thoracic sternites 3

FIGURE 19. Phylladiorhynchus integrus (Benedict, 1902), female 4.8 mm (MNHN-IU-2014-13804): A, carapace and pleon, dorsal view. B, thoracic sternites 3 and 4. C, left cephalic region, showing antennular and antennal peduncles, ventral view. D, right Mxp3, lateral view. E, right P1, dorsal view. F, right P2, lateral view. G, right P3, lateral view. H, right P4, lateral view. Scale bar: A, E–H = 1.0 mm; B–D = 0.5 mm.

FIGURE 21. Rostrum, dorsal view. A, Phylladiorhynchus euryalus n. sp., paratype male 1.8 mm (UF34732). B, P. gustavi n. sp., paratype male 1.7 mm (UF9756). C, P. heptacanthus n. sp., holotype female 2.1 mm (MNHN-IU-2017-2534). D, P. hylas n. sp., paratype female 1.6 mm (MNHN-IU-2016-495). E, P. integrirostris (Dana, 1852), male 1.6 mm (UF15285). F, P. integrus (Benedict, 1902), ovigerous female 3.2 mm (MNHN-IU-2014-13853). G, P. iphiclus n. sp., holotype ovigerous female 2.3 mm (MNHN-IU-2019-2662). H, P. janiqueae n. sp., paratype male 1.8 mm (MNHN-IU-2016-482). I, P. jeffkinchi n. sp., paratype male 2.7 mm (MNHN-IU-2014-13565). J, P. joannotae n. sp., paratype male 2.1 mm (MNHN-IU-2014-20055). K, P. joannotae n. sp., holotype ovigerous female 2.1 mm (MNHN-IU-2014-13805). L, P. koumac n. sp., paratype male 1.5 mm (MNHN-IU- 2014-20121). Scale bars: 1 mm.