Bunburia javanica, Chim & Tong, 2021

Chim, C. K. & Tong, Samantha J. W., 2021, Three new species of agathotanaids (Tanaidacea: Paratanaoidea: Tanaidomorpha) from the lower bathyal zone off southwestern Java, Indonesia, Indian Ocean with notes on the global distribution and diversity of Agathotanaidae, Zootaxa 5004 (1), pp. 67-106 : 77-83

Bunburia javanica n. sp.

( Figs 5B , 10–13 )

Bunburia sp. SJ#1: Chim & Bird (in press)

Material examined. Holotype, non-ovigerous female (3.8 mm), dissected and mounted on 17 slides ( ZRC 2020.0316 ), about 80 km south of Cilacap , Java, Indonesia, Indian Ocean, station CR42 (8°20.609’S, 108°43.036’E), 2355 m, box corer, layer 5–10 cm, sieve mesh size 300 μm, SJADES cruise, 31 March 2018.

Diagnosis. Maxilliped basis with one seta distally; palp article-4 with one seta subdistally and five setae distally. Cheliped propodus with three short and one long setulose spiniform setae and six spinules on inner margin. Pereopods 1–3 merus with one short simple and one setulose bayonet setae. Pereopods 4–6 ischium with two setae.

Description. Non-ovigerous female holotype ZRC 2020.0316

Body ( Figs 5B , 10A–B ) subcylindrical, about seven times longer than wide. Cephalothorax about 19% of body length, 1.3 times longer than wide, lateral margins convex posteriorly, pear-shaped in dorsal view; rostrum short and subtriangular; eye lobes absent.

Pereon about 65% of body length; pereonite-1 widest, trapezoidal, wider than long; pereonites 2 and 3 of subequal length, as long as wide; pereonites 4–6 of subequal width but pereonites 4 and 6 as long as wide and pereonite- 5 longer than wide; lateral shoulders weakly defined.

Pleon about 16% of body length, narrower than pereon; all five pleonites of subequal length, each 0.2 times as long as wide, pleonite-5 with one pair of simple setae; pleotelson ( Fig. 11C ) about 38% of pleon length, wider than pleonites, covered with spinules ventrally, posterior margin rounded bearing two pairs of simple setae distally.

Antennule ( Fig. 11A ) about 0.8 times as long as cephalothorax, with four articles; article-1 longest, about 56% of total length, with three simple setae medially and four (two simple and two plumose) setae distally; article-2 about 21% of total length, with four simple and one plumose setae distally; article-3 shortest, about 8% of total length, with three simple setae distally; article-4 about 15% of total length, with seven simple setae and one aesthetasc distally.

Antenna ( Fig. 11B ) about 0.6 times as long as antennule, with six articles; article-1 short, partially destroyed during dissection; article-2 about 20% of total length, with one long simple seta and some setules ( Fig. 13A ); article- 3 about 11% of total length, with one long simple seta distally; article-4 longest, about 43% of total length, with one plumose seta medially and four (three simple and one plumose) setae distally; article-5 about 19% of total length, with one simple seta distally; article-6, about 7% of total length, with five simple setae distally.

Labrum ( Fig. 11C ) hood-shaped, covered with many setules distally. Right mandible ( Fig. 11D ) small; incisor with three blunt teeth. Left mandible ( Fig. 11 D`) small; molar tapered distally; incisor with two blunt teeth; lacinia mobilis long and thick. Labium ( Fig. 11E ) with two pairs of lobes; inner lobe pointed but blunt; outer lobe membranous. Epignath and maxilla lost during dissection. Maxillule ( Fig. 11F ) long and slender; endite with 11 spiniform setae; palp with two terminal setae. Maxilliped ( Fig. 11G ) bases not fused distally, each with one simple seta distally; endite with one round process and two simple setae distally; palp article-1 naked; palp article-2 with three simple setae distally; palp article-3 with numerous setules proximally and three setulose setae distally; palp article-4 with one simple seta subdistally, one simple and four setulose spiniform setae distally and several setules on inner margin.

Cheliped ( Fig. 12A, 12 A`) pseudocoxa large, about 2.7 times longer than basis, fused ventromedially ( Fig. 10C ); basis trapezoidal, about 0.6 times as long as wide, with one simple seta dorsally; merus triangular, about 0.8 times as long as basis, with one simple seta ventromedially; carpus subrectangular, about 1.9 times longer than basis, with one simple seta dorsomedially and one short ventromedial process bearing two simple setae; propodus about 1.3 times longer than carpus, ventral margin slightly convex, palm with four spiniform setae and six spinules on inner margin distally ( Fig. 13B ), fixed finger with one simple seta ventrally, two large strongly chitinised teeth dorsodistally ( Fig. 13C ) and three simple setae on outer margin near cutting edge, strongly chitinised terminal spine blunt distally ( Fig. 13C ); dactylus and unguis together slightly wider and longer (about 1.2 times) than fixed finger; dactylus with one spiniform seta on inner margin dorsoproximally and two spiniform setae on outer margin near cutting edge; unguis strongly chitinised, blunt distally ( Fig. 13C ).

Pereopod-1 ( Fig. 12B, 12 B`) with microtrichia on most articles ( Fig. 13D ); coxa with one simple seta; basis about 6.1 times longer than wide, lateral margins parallel; ischium short, less than 0.1 times as long as basis, with one simple seta ventrally; merus about 0.4 times as long as basis, with one short simple and one setulose bayonet setae ventrodistally; carpus about 1.3 times longer than merus, with one setulose bayonet seta dorsodistally and one short setulose spiniform and one longer setulose setae ventrodistally; propodus about 1.1 times longer than carpus, with one long setulose seta on inner margin subdistally, one short setulose spiniform seta ventrodistally, one dorsal simple seta subdistally and one small spine dorsodistally; dactylus and unguis slender, together as long as propodus; dactylus with one long simple seta proximally; unguis about 1.4 times longer than dactylus, with blunt tip.

Pereopod-2 ( Fig. 12C ) similar to pereopod-1 except that basis about 5.4 times longer than wide, with one plumose seta dorsoproximally (was observed but lost prior to illustration); propodus with one short setulose spiniform seta ventrodistally, one short spine on inner margin distally, two small spines dorsodistally ( Fig. 13E ) and numerous setules along distal margin; dactylus and unguis combined length about 0.8 times as long as propodus; unguis as long as dactylus.

Pereopod-3 ( Fig. 12D ) similar to pereopod-2 but with one additional plumose seta on basis.

Pereopod-4 ( Fig. 12E ) with microtrichia on most articles; coxa with one simple seta; basis about 5.0 times longer than wide, with two plumose setae ventromedially; ischium short, less than 0.1 times as long as basis, with two simple setae ventrally; merus about 0.3 times as long as basis, with two setulose spiniform setae ventrodistally; carpus about 1.5 times longer than merus, with one simple seta dorsodistally and three setulose spiniform setae ventrodistally; propodus about 0.8 times as long as carpus, with three short spiniform setae dorsodistally and two long setulose spiniform setae ventrodistally; dactylus and unguis combined length about 1.8 times longer than propodus; dactylus curved ventrally, with one process dorsoproximally and one minute seta dorsodistally; unguis about 0.7 times as long as dactylus, with sharp tip.

Pereopod-5 ( Fig. 12F ) similar to pereopod-4 except that basis with three additional plumose setae dorsally.

Pereopod-6 ( Fig. 12G ) similar to pereopod-5 except that basis with only one plumose seta.

Pleopods absent.

Uropod ( Fig. 10D ) short—not visible from dorsal view; basal article naked; endopod with two fused articles, together about 2.1 times longer than basal article and with two (one simple and one plumose) setae medially and five simple setae distally; exopod fused with basal article forming a short acute spur bearing two simple setae distally.

Male unknown.

Etymology. The specific epithet is an adjective referring to the type locality Java Island, Indonesia. It agrees with the feminine gender of the genus Bunburia .

Distribution and habitat. Only from the type locality, at depth of 2355 m, in the 5–10 cm top layer of soft sediment.

Remarks. It is generally not recommended to describe a new species based on a single specimen. However, deep-sea material from Indonesia are very rare and our specimen provided a rare opportunity to study this species. Bunburia javanica n. sp. is the second member of the genus based on the presence of several diagnostic characters. Firstly, the short uropod does not extend beyond pleotelson, with the exopod fused to basal article forming a short spur and endopod formed by fusion of two short articles. This type of uropod has been described only in the new species, Bunburia prima Jóźwiak & Jakiel, 2012 and Paragathotanais wurundjeri Błażewicz-Paszkowycz & Bam- ber, 2012. Secondly, the propodus on pereopods 4–6 possesses three short spiniform setae dorsodistally and two long setulose spiniform setae ventrodistally. Similar pereopods are also present in Paranarthrura fortispina Sieg, 1986 but one of the propodus dorsodistal setae is much longer than the other two. In P. wurundjeri , pereopod-5 is similar to that of Bunburia , but pereopod-4 and pereopod-6 possess two (one short and one long) and four (all short) dorsodistal spiniform setae, respectively. Thirdly, the labium is devoid of medial or lateral projections. Among other members of Agathotanaidae , this type of labium can only be found in Paragathotanais medius Larsen, 2002 and several Paranarthrura species (i.e. P. bispinosa Larsen, 2005 , P. coimbrai Larsen & Bird, 2013 , P. fortispina and P. tenuimanus Larsen, 2005 ). Like B. prima , B. javanica also has fine setation on antennule article-1 and antenna article-4 but not as dense and the setules are presented as microtrichia.

Bunburia javanica was recorded off Southwest Java, Indonesia at 2355 m depth while B. prima was found between Ningaloo and Bunbury, Western Australia with bathymetric range of 205– 715 m. Even though both localities are separated by less than 3,000 kilometres in the Indian Ocean and it is not unusual for agathotanaids to exhibit wide vertical distribution (see Jóźwiak & Błażewicz-Paszkowycz 2011), there are substantial morphological differ- ences to show that B. javanica and B. prima are two distinct species. Bunburia javanica can be distinguished from B. prima by having (1) some setules on antenna article-2; (2) one long plumose seta on antenna article-4 medially; (3) one seta on maxilliped basis (as compared to none in B. prima ); (4) six instead of five setae on maxilliped palp article-4 subdistally and distally; (5) cheliped pseudocoxae fused ventromedially; (6) three short and one long setulose spiniform setae and six spinules on inner margin of chela (as compared to two short and one long setae and no spinules in B. prima ); (7) one additional short simple seta on merus of pereopods 1–3; (8) a laterodistal spine instead of a seta on propodus of pereopods 2–3; (9) two instead of one dorsodistal spines on propodus of pereopods 2 and 3; (10) two instead of one setae on ischium of pereopods 4–6. The chela fixed finger terminal spine and unguis of B. javanica are thicker and more blunt than those in the B. prima female holotype but are similar to those in the B. prima male allotype.

Figures

FIGURE 5. Agathotanaids of Southwest Java, Indonesia: (A) Agathotanais cilacapicus n. sp.; (B) Bunburia javanica n. sp.; (C) Paranarthrura sundanensis n. sp..

FIGURE 10. Bunburia javanica n. sp. Southwest Java, Indonesia. Non-ovigerous female holotype (ZRC 2020.0316): habitus, (A) dorsal and (B) lateral views; (C) cephalothorax, ventral view; (D) pleotelson and uropods, ventral view. Asterisk indicates missing part. Scale bars: 1 mm (A–C); 100 µm (D).

FIGURE 11. Bunburia javanica n. sp. Holotype female: (A) antennule, left; (B) antenna, left; (C) labrum; mandibles, (D) right and (D`) left; (E) labium; (F) maxillule; (G) maxillipeds. Asterisk indicates missing part. Scale bars: 100 µm.

FIGURE 12. Bunburia javanica n. sp. Holotype female: cheliped, right, (A) outer and (A`) inner views; pereopod-1, (B) right and (B`) left; (C–G) pereopods 2–6, right. Asterisk indicates missing part. Scale bar: 100 µm.

FIGURE 13. Bunburia javanica n. sp. Holotype female: (A) setules on antenna article-2; (B) spinules on inner margin of chela; (C) heavily chitinised parts of the chela including the fixed finger terminal spine, unguis and teeth of cutting edges (in darker colouration); (D) microtrichia on pereopod-1 propodus; (E) dorsodistal spines on pereopod-2 propodus. Scale bars: 50 µm.