Pugettia longipes, Ohtsuchi & Komatsu & Li, 2020

Ohtsuchi, Naoya, Komatsu, Hironori & Li, Xinzheng, 2020, A New Kelp Crab Species of the Genus Pugettia (Crustacea: Decapoda: Brachyura: Epialtidae) from Shandong Peninsula, Northeast China, Species Diversity 25, pp. 237-250 : 240-249

publication ID

https://doi.org/ 10.12782/specdiv.25.237

publication LSID

lsid:zoobank.org:pub:AB860A87-1BFD-47E4-B278-36DF304A9519

persistent identifier

https://treatment.plazi.org/id/52D509A6-566C-4B72-B849-13209BB9C7BE

taxon LSID

lsid:zoobank.org:act:52D509A6-566C-4B72-B849-13209BB9C7BE

treatment provided by

Felipe

scientific name

Pugettia longipes
status

sp. nov.

Pugettia longipes View in CoL n. sp.

[New Japanese name: Ashi-naga-yotsuha-mogani] ( Figs 1 View Fig , 2 View Fig , 3A View Fig , 4–6 View Fig View Fig View Fig , 7A–C View Fig , 8A–C View Fig , 9A–B View Fig , 10 View Fig , 11 View Fig )

Pugettia quadridens View in CoL (non De Haan, 1837): Shen 1937: 287– 289, text fig. 5b, c, e, h.

Materials examined. Holotype: male (17.6× 12.9 mm) ( MBM 188862 View Materials ), Kong tong Island, Yantai, Shandong, North China, 7 April 1951 . Allotype: female (15.1× 10.7 mm) ( MBM 188863 View Materials ), same locality and date as holotype . Paratypes: 3 males (12.9×9.3–14.1× 10.2 mm) ( MBM 188864), 2 females (13.3×10.3, 18.3× 13.7 mm) 2 ovigerous females (11.9×8.2, 13.7× 10.5 mm) ( MBM 188866), same locality and date as holotype.

Non-type: 1 male (13.6× 9.3 mm) ( MBM 188867 View Materials ), same data as holotype .

Description. Male. Full-grown specimens (PCL 12.9– 17.6 mm, n =3). Carapace ( Fig. 1A View Fig ) pyriform, 1.4 longer than width (mean PCL/CW±SD=1.4±0.0); surface smooth to naked eyes but closely covered with microscopic, apically flattened setae; gastric, cardiac, branchial, intestinal regions unclearly separated from each other. Gastric region ( Fig. 2A View Fig ) moderately elevated, sometimes anteriorly with short, oblique row of hooked setae on either side of midline ( Figs 1A View Fig , 2A View Fig ; mostly abraded in holotype); mesogastric, metagastric, both protogastric regions each with rudimentary protuberance (protogastric ones much closer to mesogastric one than to metagastric one) ( Fig. 1A View Fig ). Cardiac, branchial regions ( Figs 1A View Fig , 2A View Fig ) moderately elevated; mesobranchial region weakly elevated, never higher than gastric region ( Fig. 2A View Fig ), with two rudimentally tubercles apically (lateral one larger than mesial one); metabranchial region faintly elevated, with low protuberance medially. Intestinal region ( Figs 1A View Fig , 2A View Fig ) moderately elevated, separated from cardiac region, with large, low protuberance apically.

Pseudorostrum widely divergent with angles of 45– 60°. Pseudorostral spine ( Figs 1 View Fig , 2A View Fig , 3A View Fig ) 0.3 as long as PCL (PRL/PCL= 0.3 in holotype; mean PRL/PCL± SD=0.3±0.0), each with two rows of dense, hooked setae on proximal half dorsally, with single row of simple, long setae on proximal half mesially; lateral margins divergent. Front ( Figs 1 View Fig , 3A View Fig ) with median, longitudinal groove on dorsal surface. Preorbital spine ( Figs 1A View Fig , 2A View Fig , 4A View Fig ) triangular, compressed dorsoventrally, directed anterolaterally, acuminate at tip. Supraorbital eave ( Figs 1A View Fig , 4A View Fig ) elevated distolaterally, distinct from pseudorostral frontal, gastric regions ( Figs 1A View Fig , 3A View Fig ), lateral margin sinuous (or indistinctly truncated subproximally). Eyes ( Figs 3 View Fig , 4 View Fig ) large, eyestalk less than half of lateral margin in width ( Fig. 4 View Fig ). Orbital hiatus ( Figs 1A View Fig , 4A View Fig ) deep, round concavity. Postorbital lobe ( Figs 1A View Fig , 4A View Fig ) large, broad triangular, compressed dorsoventrally, directed anteriorly, slightly incurved distally, acute apically, shorter than preorbital spine, without depression basally ( Fig. 2A View Fig ). Hepatic lobe ( Figs 1 View Fig , 4 View Fig ) broad, triangular, compressed dorsoventrally, 2.3–3.0 times longer than postorbital lobe (HPL/PCL=3.0 in holotype; mean HPL/ POL±SD=2.6±0.3), directed anterolaterally, acuminate at tip, separated from postorbital lobe by shallow, lateral concavity; posterior margin slightly concave; slope line from gastric region to hepatic lobe tip nearly straight ( Fig. 3A View Fig ). Anterolateral carapace margin ( Figs 1A View Fig , 2A View Fig ) with small patch of rows of hooked setae; lateral surface inferior to anterolateral margin with rudimentary tubercle. Epibranchial spine ( Fig. 1A View Fig ) slightly longer than, or as long as postorbital lobe, distinctly shorter than hepatic lobe, directed anterolaterally, slightly incurved, obtuse at tip, positioned at posterior 0.4 of postorostral carapace length (ESL/PCL= 0.4 in holotype; mean ESL/PCL±SD=0.4±0.0), confluent to posterolateral carapace margin at base. Posterolateral carapace margin ( Fig. 1A View Fig ) faintly convex. Posterior carapace margin ( Fig. 1A View Fig ) weakly projected, rounded.

Subhepatic region ( Figs 1B View Fig , 2A View Fig ) without sparse, hooked setae. Pterygostomial region not prominently inflated, with four papiliform tubercles along pleural suture. Anterolateral angle of buccal frame ( Fig. 2A View Fig ) subrectangular, produced anteriorly, not overlapped by anterolateral angle of third maxilliped merus when closed.

Basal antennal article ( Fig. 4B View Fig ) smooth on surface, bearing low, blunt longitudinal ridge mesial to midline; anterior margin triangular, tip anterior to distolateral angle; distolateral angle moderately produced into small tooth directed anterolaterally; lateral margin extended laterally, concave, proximal end protruded roundly (sometimes with tubercle), with low tubercle basally. Antennal peduncle ( Figs 1B View Fig , 2 View Fig , 4B View Fig ) consisting of two articles flattened dorsoventrally; penultimate article ( Fig. 4B View Fig ) dilated laterally, distal end almost twice broader than proximal end; ultimate article ( Figs 1B View Fig , 2B View Fig ) two-thirds of penultimate article in length, compressed, slightly broadened distally; tip exceeding apex of pseudorostral spine.

Third maxilliped ( Figs 1B View Fig , 5F View Fig ). Ischium with shallow, broad, longitudinal groove medially. Merus with dilated, faintly upturned anterolateral angle. Exopod dilated laterally, immediately narrowed in distal one-third, mesial margin without subacute angle.

Thoracic sternum ( Figs 1B View Fig , 5A, B View Fig ). Sternite 2 with pair of small depression anteriorly. Sternites 3–4 distinctly rimed anterolaterally, slightly ridged medially; sterno-pleonal cavity with sparse, long setae on anterolateral margins ( Fig. 5B View Fig ).

Pleon ( Figs 1B View Fig , 5B View Fig ) with six pleomeres and telson; pleomeres 3–6 functionally fused, each defined by distinct suture, gradually decreasing in width. Pleomere 3 broadest, lateral margins arcuate; pleomere 4 trapezoid, shorter than fifth in midline length; pleomere 5 trapezoid; pleomere 6 also trapezoid, 0.6 of pleomere 3 in proximal width ( PW6 / PW3 = 0.6 in holotype; mean PW6 / PW3 ±SD=0.6±0.0); telson triangular, length as long as proximal width .

Chelipeds ( Figs 1 View Fig , 6 View Fig ) subequal in size and shape. Ischium ( Fig. 1B View Fig ) weakly swollen ventrally in distal half; mesial margin obtusely ridged, with pointed tip; distolateral lobe distinct, compressed, rounded apically. Merus ( Fig. 6A–C View Fig ) prismatic, length about three (2.7–3.2) times longer than width (length/height= 2.7 in holotype; mean length/ height±SD=3.0±0.0), relative length against postpseudorostral carapace length 0.4–0.5 (length/PCL= 0.5 in holotype; mean length/PCL±SD=0.5±0.0); dorsal surface ( Fig. 6D View Fig ) with indistinct longitudinal keel in proximal 0.8, with three or four, low, lamellar teeth, distalmost largest; outer surface ( Fig. 6E View Fig ) rugose, with obtuse longitudinal ridge, unarmed; ventral surface ( Fig. 6F View Fig ) smooth, with blunt ridge bearing three, low, broad teeth, proximalmost largest; inner surface ( Fig. 6G View Fig ) unarmed, depressed medially. Carpus ( Fig. 6A–C View Fig ) moderately inflated, with indistinct ridge on upper surface; lower surface irregularly rugose ( Fig. 6C View Fig ); inner margin obtusely crested, with prominent proximal lobe ( Fig. 6A View Fig ); outer margin obtusely ridged, entire ( Fig. 6B, C View Fig ). Chelae ( Fig. 7A View Fig ) more than twice (2.3–2.4) longer than height (ChL/ChH= 2.3 in holotype; mean ChL/ ChH±SD=2.4±0.1); palms moderately expanded, upper margin crested, lower margin obtuse; immovable, movable fingers with low, broad teeth in almost entire length; fingers narrowly gaping in almost entire length (when closed).

Ambulatory legs ( Figs 1 View Fig , 8A–C View Fig ) decreasing in length posteriorly, surface generally smooth to naked eyes but closely covered with microscopic plate setae. Meri subcylindrical, weakly compressed in P2, each with indistinct, upper distal tubercle ( Fig. 8A View Fig ), about eight times (length/height= 8.2 in holotype; mean length/height±SD=7.9±0.3) longer than height in P2, almost five times (5.1 in holotype; 5.3±0.2) in P3, more than four times (4.1 in holotype; 4.4±0.1) in P4, four times (4.0 in holotype; 4.0±0.0) in P5. Carpi each with shallow, medial depression on extensor surface, most distinct in P2 ( Figs 1A View Fig , 8B View Fig ). Propodi compressed in P2, weakly compressed in P3–5, with setal tufts on proximal 0.8 on flexor margin in P2, 0.6 in P3–5 ( Figs 1A View Fig , 8C View Fig ). Dactyli each with two rows of large, calcareous spines on flexor surface ( Fig. 8A, C View Fig ).

Shaft of G1 ( Fig. 9 View Fig ) slender, straight, trilobate in distal one-fourth, three lobes similar in length; dorsal lobe triangular, with rounded tip, somewhat longer than ventral lobe, weakly curved mesially ( Fig. 9A View Fig ); ventral lobe triangular, with subacute tip ( Fig. 9B View Fig ); mesial lobe triangular, with rounded tip, projecting anterolaterally, weakly twisted proximally, directed downwards, crossing dorsal lobe in lateral view ( Fig. 9A View Fig ); mesial, lateral margins from dorsal lobe to ventral lobe strongly concave medially; lateral margin with small, lobular projection near dorsal lobe basis ( Fig. 9A, B View Fig ). Shaft of G2 stout, narrowed distally, truncated apically; apex with triangular, subacute projection.

Adolescent males. Based on two specimens ( PCL 13.6 , 14.1 mm, n =2) ( Fig. 10 View Fig ) . Pseudorostral spine longer than in full-grown specimens (PRL/PCL=0.3) ( Fig. 10 View Fig vs. Fig. 1 View Fig ). Chelae relatively short (ChL/ChH=2.8, 2.9), both fingers uniformely dentate ( Fig. 7B View Fig vs. Fig. 7A View Fig ). Cheliped merus relatively shorter than in full-grown specimens (0.4 PCL vs. 0.5 PCL) ( Fig. 10 View Fig vs. Fig. 1 View Fig ). Shaft of G1 completely folded, apically trilobate as in full-grown individuals.

Female. Full-grown specimens (PCL 13.8–18.3 mm, n =5) including allotype ( Fig. 11 View Fig ). Carapace relatively less elongate than in male (mean PCL/CW±SD=1.3±0.0), more round- ed than males due to elevated hepatic region ( Figs 2B View Fig , 11A View Fig vs. Figs 1A View Fig , 2A View Fig ). Mesobranchial regions elevated more distinctly than in males ( Fig. 2A View Fig vs. Fig. 2B View Fig ). Hepatic lobe acuminate at tip, incurved distally, relatively longer (mean HpL/ PoL±SD=2.9±0.3), less laminate than in males ( Figs 2B View Fig , 11A View Fig vs. Figs 2A View Fig , 1A View Fig ); slope line from gastric region to hepatic lobe tip uneven. Pseudorostral spine relatively shorter than in males (mean PRL/PCL±SD=0.2±0.0 vs. 0.3±0.0) ( Fig. 11A View Fig vs. Fig. 1A View Fig ). Cheliped merus shorter, more slender than in full-grown males (mean length/PCL±SD=0.4±0.0 versus 0.5±0.0; mean length/height±SD=3.8±0.5 vs. 3.1±0.3) ( Fig. 11A View Fig vs. Fig. 1A View Fig ). Chelae more slender than in males, almost three times (2.9–3.0) longer than height (mean ChL/ChH±SD=2.9±0.0 vs. 2.4±0.1) ( Fig. 7C View Fig vs. Fig. 7A View Fig ), cutting edges uniformly dentated, without gapes when closed ( Fig. 7C View Fig ). Pleon ( Fig. 11B View Fig ) with six, functionally fused pleomeres, telson. Gonopore ( Fig. 5C–E View Fig ) commashaped, oblong in lateral two-thirds, elongate in mesial onethird.

Variation. Shapes and fusion degree of the postorbital and hepatic lobes are varied individually rather than ontogenetically ( Figs 1A View Fig , 10 View Fig , 11A View Fig ). Hpl/Pol increases from 1.6 to 3.0 generally in relation to size growth ( Figs 1A View Fig , 10 View Fig , 11A View Fig ). Distolateral angle of basal antennal article varies in length and sharpness ( Figs 1B View Fig , 11B View Fig ).

Remarks. The present new species closely resembles Pugettia ferox and P. quadridens . Shared characters with P. ferox include: acute, triangular preorbital spine as long as postorbital lobe; sinuous lateral margin of supraorbital eave; orbital hiatus appeared as broad concavity; shallow concavity on lateral margin between postorbital and hepatic lobes; basal antennal article clearly separated from suborbital region by basal protrusion on lateral margin; small, lobular projection at basis of G1 dorsal lobe (cf. Ohtsuchi and Kawamura 2019: figs 28 A, 33A–G). Pugettia longipes n. sp. and P. quadridens shares the following features: smooth carapace surface covered with microscopic, apically-flattened setae; rows or groups of hooked setae on carapace which can be absent in male specimens; rudimentary tuberculation on gastric, branchial regions; long, broad, basally inflated hepatic lobe; secondary sexual difference in the relative length of pseudorostral spines (only in the full-grown stage) (cf. Ohtsuchi and Kawamura 2019: figs 2–13). However, these species can be distinguished from each other by the morphological differences discussed below.

The pseudorostrum is more divergent in P. longipes n. sp. (divergent angle=45–60°) than in P. ferox and P. quadridens (30–40°) at least when compared among full-grown individuals ( Fig. 3 View Fig ; cf. Ohtsuchi and Kawamura 2019: figs 3A, B, D, E, 26 A, 34A, 37A, C, F, G).

The pseudorostral spine is relatively longer in P. longipes n. sp. ( Figs 1 View Fig , 10B, C View Fig ) than in P. ferox when compared among males (PRL/PCL: 0.3±0.0 in P. longipes n. sp. vs. 0.2±0.0 in P. ferox ) ( Ohtsuchi and Kawamura 2019: figs. 26, 35, 36), and relatively longer than in P. quadridens when compared among adolescent males (0.3±0.0 in P. longipes n. sp. vs. 0.2±0.0 in P. quadridens ) ( Ohtsuchi and Kawamura 2019: figs 3, 10). See also Ohtsuchi and Kawamura (2019: table 1).

The anterolateral margin of gastric region is poorly defined, and the slope from protogastric region to hepatic lobe tip is almost straight in males of P. longipes n. sp. ( Fig. 3A View Fig ). On the other hand, the anterolateral margin of gastric region weakly demarcated, and the slope is shallowly concave or weakly sinuous in both males and females of P. quadridens and P. ferox ( Fig. 3B, C View Fig ). This character is unique to P. longipes n. sp. among all the extant western Pacific Pugettia .

The supraorbital eave is deeply demarcated from the frontal region by a groove in P. longipes n. sp. ( Figs 3A View Fig , 4A View Fig ), whereas it is not markedly demarcated in P. quadridens and P. ferox ( Fig. 3B, C View Fig ).

The relative length of the hepatic lobe (HpL/PoL) in P. longipes n. sp. shows different growth tendencies from that of P. quadridens and P. ferox ( Fig. 12 View Fig ), but we can also see that HpL/PoL cannot fully distinguish P. longipes n. sp. from the other two species because of potentially wide overlap.

The lateral margin of the basal antennal article being clearly separated from the suborbital region at the basis distinguishes P. longipes n. sp. and P. ferox from P. quadridens , in which the article is confluent to the suborbital region ( Fig. 4B View Fig versus Ohtsuchi and Kawamura 2019: figs 4B, 28B). The basal protrusion of the lateral margin of P. longipes n. sp. resembles that of P. ferox . However, in the present new species, the protrusion is rounded ( Fig. 4B View Fig ) and never pointed as seen in large specimens of P. ferox ( Ohtsuchi and Kawamura 2019: fig. 28B).

The patterns of morphometric and morphological change of male chelae differ among these three species. The ChL/ ChH of P. longipes n. sp. changes from 2.8 (median) in adolescents to 2.4±0.1 (mean±SD) in full-grown males, and this pattern resembles P. ferox , in which ChL/ChH changes from 2.8±0.0 in adolescents to 2.3± 0.1 in full-grown males ( Ohtsuchi and Kawamura 2019: table 1). On the other hand, the chelae of P. quadridens is relatively shorter than in P.longipes n. sp. and P. ferox at all ontogenetic stages: the ChL/ ChH changes from 2.4±0.0 in adolescent males to 2.0±0.0 in full-grown males ( Ohtsuchi and Kawamura 2019: table 1). In addition, P. longipes n. sp. differed in the chelae dentition from both of the other two species when compared among full-grown males, although the chela of adolescent males are similar in general shape and dentition on both fingers: the chela has a narrow gap when both fingers are closed, and the movable finger is uniformly dentate in P. longipes n. sp. ( Fig. 7A View Fig ). In P. quadridens , the chela is widely gaped, and the movable finger bears a group of two or three, large, isolated teeth on the proximal one-third ( Fig. 7G View Fig ) and has narrow gaps, and the movable finger bears no peculiar teeth in P. ferox ( Fig. 7D View Fig ).

The cheliped merus is shorter than the P2 merus in P. longipes n. sp. in any of the ontogenetic stages ( Figs 1 View Fig , 10, 10 View Fig ), whereas in P. quadridens and P. ferox , the P2 merus is significantly longer than the cheliped merus only in fullgrown males ( Fig. 13 View Fig , Tukey-Kramer HSD test, p <0.01). It should also be remarked that the cheliped merus is relatively shorter in P. longipes n. sp. than in P. quadridens and P. ferox when compared among full-grown males (mean length/ PCL±SD: 0.5±0.0 in P. longipes ; 0.6±0.0 in P. quadridens and P. ferox ) ( Fig. 1A View Fig vs. Ohtsuchi and Kawamura 2019: figs 3A, 26 A) (Tukey-Kramer HSD, p <0.01).

The tri-dentate longitudinal ridge on the dorsal surface of the cheliped merus is more lamellar in P. longipes n. sp. ( Fig. 6F View Fig ) than in the other two species (cf. Ohtsuchi and Kawamura 2019: figs 5E, 29E). The distalmost tooth is moderately high and acuminate in P. longipes n. sp. and P. ferox , but it is low and blunt in P. quadridens . However, this character should be used with caution because it is often rudimentary in small, immature specimens in P. quadridens and P. ferox ( Ohtsuchi and Kawamura 2019) .

In each ambulatory leg, the relative length of the merus compared to PCL is greater in P. longipes n. sp. than in the other two species when compared among the same ontogenetic stages (Tukey-Kramer HSD test, p <0.05) ( Fig. 13 View Fig ). All the ambulatory legs have meri that are much more slender in P. longipes n. sp. than in the other two species ( Table 1). For example, the P2 merus is much more slender in P. longipes n. sp. (mean length/height±SD: 7.9±0.3) than in the other two species (5.7± 0.3 in P. quadridens ; 6.3± 0.9 in P. ferox ; Tukey-Kramer HSD test, p <0.05) ( Fig. 8 View Fig ).

The absence of a small, lobular projection at the G1 dorsal lobe basis, and the elevation of the lateral margin of G1 apex (higher than mesial margin), distinguish P. quadridens from both P. longipes n. sp. and P. ferox ( Fig. 9 View Fig ). In the latter two species, the mesial margin of the G1 apex is continuous to the upper margin of the ventral lobe ( Fig. 9A View Fig ), but it is distinct in P. ferox ( Fig. 9C View Fig ). See also Ohtsuchi and Kawamura (2019: figs 9A–D, 33A–G).

Shen (1937) provided a comparison table between P. minor Ortmann, 1893 and P. quadridens based on some specimens from Kiachow Bay (=Jiazhou Bay), Shandong, northern China. Although we have no opportunity to examine his specimens in the present study, his P. quadridens should be attributed to our new species, since it shows the proportionally long hepatic lobe [estimated HpL/PoL= 3.8 in 17.3 mm PCL, based on text fig. 5b in Shen (1937)] and the characteristic structure of G1 ( Shen 1937: text-fig. 5b, c, e, h). The shape of the basal antennal article must have belonged to the same specimen as previous characters, but unfortunately, it cannot be referred to any known species of Pugettia because its basis was incompletely drawn ( Shen 1937: text fig. 5c). The transverse ridge on the thoracic sternum was not found in our specimens, but this is not a useful character: in some Pugettia , the sternite 1 is slightly depressed anteriorly and the boundary between sternites 1 and 2 appears as if there is a transverse ridge in some cases ( Figs 1B View Fig , 5A View Fig ). Despite many previous records of Pugettia in Northeast Asian waters (see Discussion in Ohtsuchi and Kawamura 2019), we found no further records of P. longipes n. sp. at least based on the figures and drawings. If possible, however, it is worth re-examining the non-figured specimens examined in these previous studies.

Distribution. This species is at present known only from the both northern and southern coast of Shandong Peninsula, Northeast China ( Shen 1937; this study). Although habitat and depth were not recorded, our specimens were likely collected from shallow water because they were originally preserved in the same glass jar with P. ferox (MBM 160513), which is known mainly from depths shallower than 20 m ( Ohtsuchi and Kawamura 2019).

Etymology. This species was named “ longipes ” alluding to their long, ambulatory legs.

MBM

San Jose State University, Museum of Birds and Mammals

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Epialtidae

Genus

Pugettia

Loc

Pugettia longipes

Ohtsuchi, Naoya, Komatsu, Hironori & Li, Xinzheng 2020
2020
Loc

Pugettia quadridens

Shen, C. J. 1937: 287
1937
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