Laticallichirus grandis ( Karasawa & Goda, 1996 ) Komai & Yokooka & Henmi & Itani, 2019

Komai, Tomoyuki, Yokooka, Hiroyuki, Henmi, Yumi & Itani, Gyo, 2019, A new genus for “ Neocallichirus ” grandis Karasawa & Goda, 1996, a ghost shrimp species (Decapoda: Axiidea: Callianassidae) heretofore known only by fossil materials, Zootaxa 4604 (3), pp. 461-481 : 466-477

publication ID	https://doi.org/ 10.11646/zootaxa.4604.3.4
publication LSID	lsid:zoobank.org:pub:D22B3630-1B33-4B8B-A005-EE425A77C8ED
persistent identifier	https://treatment.plazi.org/id/E63A2937-3417-BD20-BFBE-E15AFB53FE6E
treatment provided by	Plazi
scientific name	Laticallichirus grandis ( Karasawa & Goda, 1996 )
status	comb. nov.

Treatment

Laticallichirus grandis ( Karasawa & Goda, 1996) n. comb.

( Figs. 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Callianassa View in CoL sp. –– Kato & Koizumi 1992: 49, fig. 3-3. Calliax sp. –– Karasawa & Tanaka 1994: 12, figs. 2-1–12. Neocallichirus sp. –– Karasawa et al. 1995: 128, fig. 2. “ Neocallichirus ” grandis Karasawa & Goda, 1996: 1 , fig. 1. –– Karasawa 1997: 33, pl. 5, figs. 1–4. Neocallichirus grandis . –– Kato & Karasawa 1998: 5, pl. 2, figs. 7–16. –– Kato 2001: 40. –– Schweitzer et al. 2006: 115 (list). Grynaminna grandis . –– Obata & Hayashi 2001: 46, figs. 3.1–12. –– Kato 2003: 159. –– Hyžný & Karasawa 2012: 65, fig.

1A–H. –– Karasawa et al. 2014: 59, fig. 5.1–5.3. –– Hyžný & Klompmaker 2015: fig. 7A, 412 ( Table 1 View TABLE 1 ). –– Ando et al.

2016: 18, figs. 3.3–10. –– Ando & Kawano 2017: 85, fig. 2.9–2.20. Podocallichirus grandis . –– Karasawa et al. 2006: 127, pl. 2, figs. 1–6. –– Kobayashi et al. 2008: 111. –– Schweitzer et al. 2010:

39 (list).

Recent material examined. CBM-ZC 15247, male (cl 18.2 mm, tl ca 69 mm), Inno River estuary, Numazu, Shizuoka Prefecture, 35°01.07’N, 138°53.14’E, 20–50 cm deep at low tide, 30 March 2017, yabby pump, coll. H. Yokooka; CBM-ZC 15248, 1 male (cl 12.7 mm, tl ca 50 mm), same data as CBM-ZC 15247; CBM-ZC 15249, 1 female (cl 16.1 mm, tl ca 65 mm; DNA voucher), same locality as CBM-ZC 15247, 18 March 2017, yabby pump, coll. R. Tagashira ; CBM-ZC 15250, 1 female (cl 14.5 mm), Utsuga , Tosa, Kochi Prefecture, 33°25.58’N, 133°26.21’E, 10–20 cm deep at low tide, 25 February 2016, yabby pump, coll. Y. Henmi. GoogleMaps

Fossil material examined. CBM-PI 0 0 288, fragments of major and minor chela, cliff at Sakurai, Kisarazu, Chiba Prefecture, 35°21.30’N, 139°55.21’E, Kioroshi Formation; CBM-PI 0 0 340, fragments of chela, cliff at Toyonari, Ichihara, Chiba Prefecture, 35°26.40’N, 140°04.43’E, Kioroshi Formation; CBM-PI 0 0 399, fragments of chelipeds, including 1 merus of major cheliped, cliff at Otake, Inba, Inba District, Chiba Prefecture, 35°47.17’N, 140°14.12’E, Kioroshi Formation.

Diagnosis. See above generic diagnosis.

Description. Body ( Figs. 1 View FIGURE 1 , 6 View FIGURE 6 ) elongate in general form.

Carapace ( Figs. 1 View FIGURE 1 , 2A, B View FIGURE 2 ) subequal in length to anterior 2 pleomeres combined; frontal margin with acute, narrowly triangular rostral spine flanked by bluntly triangular projection located just lateral to eyestalks; rostral spine straight, directed forward, reaching to midlength of eyestalks. Surface anterior to dorsal oval (just proximal to rostral base) without paired setae; dorsal oval well defined, smooth, length of oval about 0.7 carapace length; marginal groove of oval across anterior midline, deepest in posterior midline; cardiac region bulbous; hepatic region fairly sclerotized but without armature; branchiostegite otherwise soft, membranous; linea thalassinica extending over entire length of carapace; anterolateral margin deeply excavate at base of antenna.

Thoracic sternite 7 (sternite of pereopods 4) ( Fig. 1B View FIGURE 1 ) medially forming sub-rhomboidal, sclerotized shield; ventral surface having interrupted Y-shaped groove, surface anterior to obliquely transverse grooves convex, extending to sternite 6 between enlarged coxae of pereopods 4; areas lateral to median shield membranous.

Eyestalks ( Fig. 2A, B View FIGURE 2 ) contiguous, not reaching distal margin of article 1 of antennular peduncle; anterolateral margins convex, tapering to subacute distomesial projection; distinct, pigmented cornea located at anterolateral part of eyestalk, no extension of dark pigment seen in eyestalks.

Antennular peduncle ( Figs. 1 View FIGURE 1 , 2A, B View FIGURE 2 ) longer and stouter than antennal peduncle, 0.6 times as long as carapace. Article 1 dorsally invaginated to form statocyst occluded by setae, overlaid by eyestalk. Article 2 subequal in length to article 1, article 3 about 2.3 times length of article 2, gradually narrowing distally; articles 2 and 3 with dense, ventromesial and ventrolateral rows of long, anteroventrally directed setae. Upper flagellum slightly longer than article 3 of peduncle, subdistally with aesthetascs; lower flagellum slightly longer, with much denser and longer setation than upper flagellum, but subequal in general width to upper flagellum.

Antennal peduncle ( Figs. 1A View FIGURE 1 , 2A, B View FIGURE 2 ) falling slightly short of midlength of article 3 of antennular peduncle. Article 1 with dorsolateral carina arched to form low lip just above excretory pore, dorsally with tuft of short setae and ventrally with tuft of longer setae. Article 2 with prominent tuft of long setae on laterodistal portion. Article 3 short, with numerous long setae, directed anteroventrally, on ventral surface. Article 4 longer than combined lengths of articles 1–3, laterally with few long setae, tufts of long setae on lateral surface proximally and subterminally. Article 5 subequal in length and slightly narrower than article 4, setation limited to few tufts of long setae on dorsal surface. Flagellum longer than carapace with sparse short to long setae arising chiefly at distal margin of each article.

Mouthparts without distinctive features (not illustrated). Maxilliped 3 ( Fig. 4A, B View FIGURE 4 ) without exopod. Ischiummerus broadly operculiform, 1.2–1.3 times as long as wide. Ischium subrectangular, broadened distally, distal width about 1.4 times of length measured along upper margin; upper margin sharply edged; lateral surface shallowly depressed proximally; proximal lower margin rounded, slightly produced; mesial surface with setose carina adjacent to upper margin, without even trace of crista dentata. Merus subrectangular, distinctly wider than long; upper margin arcuate; articulation with carpus slightly produced, exceeding broadly convex distal margin lower to carpal articulation. Carpus with gently convex upper and strongly convex lower margins, about 1.7 times as long as greatest width; lateral surface bluntly ridged along midline. Propodus large, subrectangular, 1.4 times as wide as long; upper margin slightly convex, while lower margin strongly convex. Dactylus slender, digitiform, slightly shorter than propodus, slightly curved; rounded terminus bearing numerous bristle-like, stiff setae.

Branchiae limited to single rudimentary arthrobranch on maxilliped 2 and pair of arthrobranchs on maxilliped 3 and pereopods 1–4.

Major cheliped located on left side in all specimens examined, shape and ornamentation sexually dimorphic. Major cheliped of male ( Fig. 3 View FIGURE 3 A–C) massive, proportionally larger than those of females. Ischium slender; upper margin noticeably sinuous; lower margin nearly straight, with row of small blunt spines increasing in size distally. Merus 1.5 times as long as high, with upper margin gently convex, bluntly carinate over entire length; outer face divided into 2 facets by blunt median ridge; inner surface nearly flat, upper distal angle forming a prominent condyle articulating to carpus; lower margin produced into strongly convex lobe, serrated with evenly spaced, triangular spines (those spines largest medially), but without hook-like process or differentiated spine. Carpus wide (height about 1.1 times length), subquadrate, upper and lower margins sharply keeled, nearly parallel, terminating in angular upper and lower corners; proximal margin broadly convex; outer surface gently convex, glabrous; inner surface medially faintly convex, with upturned upper and lower margins and with wide proximal concavity accommodating distal part of merus when cheliped flexed; few tufts of short setae on upper margin and row of tufts of longer setae on lower margin mesially. Propodus wide, heavy; palm as long as high and 1.2 times as long as carpus; outer surface smooth, with scattered tufts of short setae particularly around base of fixed finger; inner surface of palm smooth, almost glabrous except for few tufts of short setae; upper margin sharply carinate over entire length, flanked by rows of tufts of short setae, upper distal angle produced; lower margin sharply keeled, but not extending onto fixed finger, with rows of tufts of short to moderately long setae extending onto fixed finger; deep excavation present inferior to base of dactylus; outer distal margin at base of dactylus gently convex, minutely tuberculate. Fingers leaving distinct hiatus when closed. Fixed finger shorter than palm, slightly curving, with well-defined separation of inner and outer occlusal margins, inner margin unarmed but forming rounded carina extending slightly onto palm, outer margin bearing prominent subrectangular, molar-like tooth proximal to midlength. Dactylus 0.6 times as long as palm, terminating in gently curved tip crossing outer side of fixed finger; upper margin rounded, non-carinate, with row of tufts of stiff setae; occlusal margin with 1 prominent molar-like tooth proximally, separated from minutely denticulated distal margin by deep U-shaped notch.

Major cheliped of female ( Fig. 5A View FIGURE 5 ) less massive than that of male, armature generally weaker. Ischium with 1 small subdistal spine followed by row of faint tubercles on lower margin. Lower margin of merus less convex than in male, with weaker spines. Palm 1.1 times as long as high, slightly narrowing distally; fixed finger slightly shorter than palm, slightly curved, outer occlusal margin with triangular tooth proximal to midlength. Dactylus 0.8 times as long as palm; occlusal margin slightly sinuous, with faint denticles, with shallow notch corresponding to occlusal tooth on dactylus.

Minor cheliped ( Fig. 3D, E View FIGURE 3 ) distinctly smaller than major cheliped. Ischium with upper margin faintly sinuous; lower margin also faintly sinuous, with 1 tiny subdistal spine followed by row of minute granules. Merus unarmed; upper and lower margins gently convex; outer surface gently convex in general, but lower distal part shallowly depressed to accommodate proximal part of carpus when cheliped flexed. Carpus subtrapezoidal, slightly widened distally, as wide as long; upper margin non-carinate, with 2 conspicuous tufts of setae (1 distal and 1 middle), terminating in angular distal corner; lower to proximal margins sharply carinate, flanked by tufts of setae, terminating in subacute distal corner; outer surface gently convex, glabrous; inner surface also generally convex, glabrous. Palm slightly shorter than carpus, about as long as high, slightly narrowing distally; outer and inner surfaces similarly convex, glabrous; upper margin carinate in proximal two-thirds, rounded in distal one-third, with 2 rows of tufts of setae; lower margin (including fixed finger) slightly sinuous, sharply carinate to proximal half of fixed finger, flanked by rows of tufts of setae extending onto fixed finger. Fixed finger slightly curved, terminating in small calcareous claw; wide occlusal surface delimited by blunt carinae, proximal half forming deep concavity, bearing numerous tufts of stiff setae along outer and inner occlusal margins, outer occlusal margin with some denticles or tubercles proximally. Dactylus 1.6 times as long as palm, gently curving, terminating in small calcareous claw, crossing inner side of fixed finger; rounded upper surface with row of prominent tufts of setae; outer surface with row of tufts of long setae along adjacent to occlusal margin; outer occlusal margin unarmed, inner occlusal margin less clearly delimited, also unarmed.

Pereopod 2 ( Fig. 4C View FIGURE 4 ) chelate, strongly compressed laterally. Ischium short, lower distal corner produced. Lower margins of merus and carpus lined with dense long setae. Merus with upper margin straight in proximal 0.7, sloping in distal 0.3; narrow, flattened lower surface flanked by blunt ridges. Carpus subtriangular, about twice as long as high; upper margin with dense long setae, produced distally into short, blunt projection. Chela subtriangular; lower margin of propodus nearly straight, with long setae proximally and reduced in length distally, lower proximal corner rounded; occlusal margins of both fingers corneous, terminating in rounded, small corneous claws; upper margin of palm very short, convex, with tuft of long setae; dactylus about twice as long as palm, upper margin straight except for convex proximal part, with long stiff setae reducing in length distally.

Pereopod 3 ( Fig. 4D, E View FIGURE 4 ) with ischium short, lower margin slightly sinuous with produced distal corner. Merus length 2.5 times high; upper margin nearly straight in proximal 0.7, sloping in distal 0.3; lower margin slightly convex. Carpus subtriangular, distinctly widened distally; articulation to propodus located at middle of distal margin, either side of articulation truncate. Propodus outer surface with dense short setae upper to naked midline, with scattered tufts of short setae lower to midline; articulation with carpus located at middle of W-shaped proximal margin, lower distal margin weakly bilobate; distal margins of both lobes with dense fringe of stiff setae; subtruncate, lower proximal margin forming prominent “heel”, exceeding beyond lower margin of carpus. Dactylus broad, sub-rhomboidal, terminating in minute, corneous claw; upper margin with dense stiff setae; outer surface with few tufts of short stiff setae; lower margin nearly straight, with dense short setae.

Pereopod 4 ( Fig. 4 View FIGURE 4 F–H) semichelate (cf. McLaughlin 1997). Ischium with produced lower distal angle. Merus with slightly convex upper and nearly straight lower margins. Carpus narrower than merus at base, widened distally; narrow, flattened lower surface formed by blunt ridges. Propodus subrectangular, with lower distal process conspicuous, deflexed, rounded apex with cluster of minute spiniform setae; lower margin sinuous, with dense brush of setae extending onto lower part of inner surface; outer surface with fields of dense setae on either side of naked midline. Dactylus tear-shaped; upper margin arched, terminating in short, outwardly directed corneous claw; outer surface with dense covering of setae, longest on lower side.

Pereopod 5 (Fig. I, J) chelate. Ischium short. Merus slightly widened distally, slightly arcuate. Carpus elongate, widened distally, with convex upper margin. Propodus stout, widest at midlength, with dense field of long, close-set setae on distal two-thirds of outer, inner and lower surfaces; upper margin strongly arcuate; fixed finger not deflected, terminally pectinate. Dactylus minutely denticulate on terminal margin, extensor surface with dense setation. Both fingers terminally rounded, occlusal surfaces spooned.

Pleonal somites ( Figs. 1 View FIGURE 1 C–E, 6) mostly smooth dorsally. Pleomere 1 wider posteriorly, subtriangular in dorsal view; tergite broadly trapezoidal, weakly sclerotized; membranous area of either lateral side without sclerite; sternite with posteriorly diverging, narrow lateral sclerites forming bases of pleopods 1; membranous parts without any pattern of small sclerites. Pleomere 2 distinctly wider than long, tergite and pleura entirely weakly sclerotized; posterolateral lobe below short, longitudinal sclerotized line bearing tuft of long setae posteriorly on surface; tergite entirely membranous. Pleomeres 3–5 tergites each with pair of finely setose, membranous, subcircular or suboval areas laterally, that of tergite 3 more posterolaterally positioned than in tergites 4 and 5, that of tergite 5 smallest; each ventrolateral margin forming weak shoulder (shoulder on pleomere 3 more posteriorly located than in pleomeres 4 and 5); lateral outlines of pleomeres 3–5 convex in dorsal view. Tergites of pleomeres 3 and 4 each with cluster of fine setae on posterolateral margins just mesial to posterolateral sutures, those of pleomere 5 each with tuft of short setae; posterolateral sutures of pleomere 3 bifurcate anteriorly, those of pleomeres 4 and 5 simple, converging anteriorly; posterolateral corners of pleomere 5 forming small condyle articulating to pleomere 6. Pleomere 6 subtrapezoidal in dorsal view, narrowing posteriorly; tergite convex, without lines of short setae anterior to posterolateral groove; posterolateral groove transverse, forming distinct notch on lateral margin; lateral margin anterior to lateral notch strongly convex; posterior dorsal surface with shallow median groove; posterolateral lobes each with prominent tuft of long setae adjacent to ventrolateral margin; posterodorsal margin with distinct notches separating posterolateral lobes, otherwise slightly convex with faint median notch, with 2 pairs of tufts of long setae.

Pleopod 1 of male and female both uniramous, composed of 2 articles. In male, pleopod 1 ( Fig. 2C View FIGURE 2 ) small, strongly compressed, directed anteromesially, about 0.4 length of pleopod 2; terminal article 0.7 length of proximal article, rounded distally, with several long setae on terminus to lower margin. In female ( Fig. 5C, D View FIGURE 5 ), entire pleopod 1 sinuous, total extended length slightly shorter than that of pleopod 2; proximal article arcuate, bearing low convexity slightly proximal to midlength; distal article longer than proximal article, proximal half thickened, distal half flattened, flexible; both articles bearing long setae, sometimes forming tufts.

Pleopod 2 of male and female biramous, with appendix interna on endopod. In male ( Fig. 1 View FIGURE 1 D–F), entire pleopod 2 strongly flattened; protopod subtriangular with obliquely truncate distal margin; exopod subequal in length to endopod but not reaching distal margin of exopod, almost naked except for few short marginal setae on outer margin, slightly curved inward, tapering to rounded apex; endopod about twice as wide as exopod, slightly curved inward, divided into two parts by obliquely transverse suture clearly visible on posterior surface; proximal part entirely naked; distal part with row of setae on outer margin, extending onto terminal margin; terminal margin slightly bilobed, outer lobe rounded, inner lobe subacutely pointed at inner angle, with tuft of long setae. In female ( Fig. 5E, F View FIGURE 5 ), protopod subtriangular; rami subequal in length, although exopod falling slightly short of endopod; endopod divided into two parts by obliquely transverse suture extending from base of appendix interna; distal part triangular with narrowly rounded apex; appendix interna digitiform, widest at midlength, arising at about distal 0.2 of endopod; inner margin of endopod proximal to appendix interna slightly convex; exopod widest distal to midlength, terminal margin rounded.

Pleopods 3–5 pairs (cf. Fig. 2G, H View FIGURE 2 ) forming large, posteriorly cupped fans when cross linked by hooked setae of appendices internae on opposed (mesial) margins of endopods. Protopods flattened, distinctly wider than long; distomesial margin truncate; proximomesial margin strongly concave; anterior (upper) surfaces each with small tubercle at condylar articulation with exopod. Endopods each subtriangular; stubby appendix interna ( Fig. 2I View FIGURE 2 ) demarcated by sutures where embedded in endopod, offset slightly from mesial margin of endopod, with covering of hooked setae on subtriangular mesial face. Exopods each with pattern of simple or branched transverse sutures on anterior (upper) lateral surface; anterior (upper) surface distinctly ridged along midline; marginal area of posterior (lower) side with fine transverse sutures.

Telson ( Fig. 1E, F View FIGURE 1 ) subrectangular, widest at about level of midlength, 1.9 times as wide as long; lateral margin bluntly angular; posterior margin faintly concave, unarmed, with prominent tuft of long setae at rounded outer angles; dorsal surface with low transverse ridge armed with row of about 30 tiny spiniform setae and median tuft of long setae anterior to midlength and 1 pair of long setae anterolaterally.

Uropod ( Fig. 1E View FIGURE 1 ) with protopod unarmed, divided into two parts by transverse suture. Proximal article of exopod with 2 small spine or tubercle on upper surface. Endopod subovate, about 1.7 times as long as wide, just reaching distal margin of exopod, tapering to rounded terminus; posteromesial margin with fringe of setae extending to terminus and forming cluster. Exopod broad, with thick anterodorsal plate falling well short of distal margin; posterodistal edge of plate bearing spiniform setae increasing in length toward mesial angle and grading to thinner, dense, elongate setae of exopodal margin; anterior margin slightly sinuous, with setal row on lower side; junction between anterior and outer margins bluntly angular; outer margin broadly convex, with thick setae; inner margin faintly convex, glabrous.

Color in life. Body and appendages generally white or yellowish white, yellowish digestive gland visible in pleomeres 1 and 2; cornea white or pale gray.

Distribution. Our specimens came from only two locations of the mainland of Japan, Numazu, Shizuoka Prefecture (Suruga Bay) and Tosa, Kochi Prefecture (Uranouchi Inlet, Tosa Bay); shallow subtidal.

Habitat. Three specimens from Inno River estuary, Numazu, Shizuoka Prefecture ( Fig. 8A View FIGURE 8 ), burrowed deeply in the substratum consisting of muddy-sand mixed with gravel and fist-sized rock. The specimen from Utsuga, Tosa, Kochi Prefecture ( Fig. 8B View FIGURE 8 ) was extracted from fine sand on the interior of a small bay. The species occurs in estuarine and inner bay environments.

Remarks. Laticallichirus grandis n. comb. was originally described by Karasawa & Goda (1996) as “ Neocallichirus ” grandis on the basis of material from Takamatsu, Akabane-cho, Aichi Prefecture (middle Pleistocene Toyohashi Formation, Atsumi Group; 0.44±0.18 Ma). The holotype consists of major right and minor left chelipeds; the paratypes consist of various fragments of major and minor chelipeds. In the original description, Karasawa & Goda (1996) referred Callianassa sp. recorded by Kato & Koizumi (1992) from the upper Pleistocene Shimosueyoshi Formation in Kanagawa Prefecture, and Neocallichirus sp. recorded by Karasawa et al. (1995) from the Pleistocene Ryukyu Group to their new species. They also noted the occurrence of the species in the Seto Inland Sea, off Hakatajima, Hakata-cho, Ehime Prefecture. Prior to this original description, Karasawa & Tanaka (1994) reported the same species as Calliax sp. Subsequently, this species has been recorded from the lower to middle Pleistocene of various Japanese localities, ranging from the Kanto District to Tanegashima Island (e.g., Kato & Karasawa 1998; Kato 2001; Obata & Hayashi 2001; Karasawa et al. 2014; Ando et al. 2016; Ando & Kawano 2017). In addition, Kato & Karasawa (1998) and Obata & Hayashi (2001) regarded the record of unidentified callianassid chelipeds from the Holocene Nanyo Formation, Aichi Prefecture (Tokay Fossil Society 1977) as representing the present species, although two different forms were recognized in those chelipeds. As seen in the given synonymy, the generic assignment of the species has been in the state of flux without information on soft parts not preserved in the fossils. We did not try to review those fossil records because it is beyond the scope of this study.

In addition to the above mentioned characteristics for comparison with other callichirine taxa, Laticallichirus grandis n. comb. is characteristic in having a transverse row of minute spiniform setae on the dorsal surface of the telson. Among species of Callichirinae , similar trait is also seen only in Balsscallichirus balssi (cf. de Saint Laurent & Le Loeuff 1979), although the number of spiniform setae is much fewer in the latter species.

We have sampled infaunal decapods in various localities of the Japanese Archipelago, but only four specimens of Laticallichirus grandis n. comb. have been collected, from only from two locations, namely Suruga Bay and Tosa Bay. On the other hand, the fossil records suggest that the species was locally quite common in the Pleistocene. It is likely that the species prefers the subtidal zone, which is not easy to access for sampling.