Birdotanais songkhlaensis, Kakui & Angsupanich, 2012

Kakui, Keiichi & Angsupanich, Saowapa, 2012, Birdotanais Songkhlaensis, A New Genus And Species Of Nototanaidae (Crustacea: Tanaidacea) From Thailand, Raffles Bulletin of Zoology 60 (2), pp. 421-432 : 423-426

publication ID	https://doi.org/ 10.5281/zenodo.5349855
publication LSID	lsid:zoobank.org:pub:65E6DFE5-1ACF-4D60-AC57-C5E81FBE1DFF
persistent identifier	https://treatment.plazi.org/id/0D2687D1-C979-6030-818E-FE67FB446D03
treatment provided by	Tatiana
scientific name	Birdotanais songkhlaensis
status	sp. nov.

Treatment

Birdotanais songkhlaensis View in CoL , new species

( Figs. 2–7 View Fig View Fig View Fig View Fig View Fig View Fig )

Etymology. — The specific name is an adjective referring to the type locality.

Holotype. — Male ( ZRC 2012.0137 View Materials , length 2.15 mm, 4 slides and 1 vial), Lower Songkhla Lagoon (07°11.83'N 100°35.11'E), Thailand, 0.7 m depth, salinity 30 psu, clay bottom, 0.05 m 2 Tamura grab, coll. S. Angsupanich, 7 Feb.2009. GoogleMaps

Paratypes. — 2 males (ZIHU-4132, length 2.14 mm, 2 slides and 1 SEM stub; ZIHU-4133, 1.86 mm, 1 vial) and 7 females (ZIHU-4134, 2.03 mm, with oostegites, 6 slides and 1 vial; ZIHU-4135, 1.97 mm, with oostegites, 3 slides, 2 SEM stubs, and 1 vial; ZIHU-4136, 1.73 mm, without oostegites, 5 slides and 1 vial; ZIHU-4137, 1.91 mm, with 4 eggs, 5 slides and 1 vial; ZIHU-4138, 2.06 mm, without oostegites, 1 slide and 1 vial; ZIHU-4139, 1.86 mm, with oostegites, 1 vial; NSMT-Cr 21981, 1.77 mm, 1 vial), same data as for holotype GoogleMaps .

Description. — Holotype male. Body ( Fig. 2A, C View Fig ) cylindrical but slightly flattened dorsoventrally, 7.8 times as long as wide. Cephalothorax 0.27 times total body length, nearly twice as long as wide, with one pair of lateral setae posterior to eyes; dorsal region smooth. Pereonites each with one pair of lateral setae. Pereonite 1 rectangular, wider than long, with one pair of dorsolateral setae. Pereonites 2–6 almost square; pereonite 4 with one pair of dorsolateral simple setae. Pleon 0.21 times total body length. Pleonites as wide as pereon; all similar in shape, without epimeral setae. Pleotelson slightly narrower than pleonites, wider than long, with round end, one pair each of lateral and posterolateral simple setae, and two pairs of simple setae at posterior tip.

Antennule ( Fig. 3A, a View Fig 1 View Fig ) 0.70 times cephalothorax length. Article 1 with one mid-outer, one disto-outer, and one disto-inner simple setae, and several broom setae. Article 2 0.28 times as long as article 1, with one outer and one inner simple setae and one broom seta in distal region. Article 3 0.73 times article 2 length, with four distal aesthetascs. Article 4 0.45 times article 3 length, with five simple setae, two broom setae, and three aesthetascs.

Antenna ( Fig. 3B, b View Fig 1 View Fig ) 0.75 times length of antennule, with six articles. Article 1 naked. Articles 2 and 3 each with one dorsodistal simple seta; article 2 at least twice as long as article 3. Article 4 longest, longer than articles 1–3 combined, with one middle and several distal broom setae. Article 5 0.6 times article 2 length, 0.3 times article 4 length, with one distal seta. Article 6 0.1 times article 5 length, with six simple setae.

Mouthparts reduced. Maxilliped ( Fig. 3C View Fig ) bases completely fused, each with one ventrodistal simple seta at insertion of palp. Endites completely fused, naked. Palp with four articles; article 4 with four simple setae at tip. Maxillular palp ( Fig. 3D View Fig ) located posterolateral to maxilliped, with two simple setae at tip. Epignath ( Fig. 3E View Fig ) narrow, curved; tip setulate.

Cheliped ( Fig. 3F, f View Fig 1 View Fig ) basis with free posterior portion, and one outer simple seta. Merus triangular, with one ventral simple seta. Carpus rectangular, almost twice as long as wide, with one dorsodistal and two ventral simple setae. Chela subchelate. Propodal palm with five inner setae at insertion of dactylus, two simple setae on ventral margin, and two distal triangular processes, bearing one and three simple setae, respectively. Fixed finger developed from subdistal region of propodal palm, without claw. Dactylus about 3.2 times as long as fixed finger, with one inner proximal seta; cutting surface with two proximal spiniform setae and two proximal processes.

Pereopod 1 ( Fig. 4A View Fig ) 0.28 times total body length, longest among pereopods. Coxa with one simple seta. Basis 0.32 times total pereopod 1 length, cylindrical, slightly arched, narrow (4.7 times as long as wide), with one broom seta. Ischium and merus with one ventral seta. Carpus 1.3 times as long as merus, with four distal simple setae. Propodus as long as carpus, with one ventral simple seta. Dactylus-unguis 1.43 times as long as propodus, naked. Unguis 1.64 times as long as dactylus. Pereopod 2 ( Fig. 4B View Fig ) 0.7 times as long as pereopod 1. Coxa and ischium like those of pereopod 1. Basis cylindrical, narrow (3.1 times as long as wide), with two dorsal broom setae. Merus with one simple and one spiniform setae in ventrodistal region. Carpus 1.62 times as long as merus, with one dorsodistal and one ventrodistal simple setae. Propodus 0.65 times as long as carpus, with one ventral spiniform seta. Dactylus-unguis 1.2 times as long as propodus, naked. Unguis 1.5 times as long as dactylus. Pereopod 3 ( Fig. 4C View Fig ) similar to pereopod 2, except that basis has one additional outer broom seta. Pereopod 4 ( Fig. 4D View Fig ) shortest among pereopods. Basis thick (twice as long as wide), with two dorsal and two ventral broom setae. Ischium wider than long, with two ventrodistal simple setae. Merus with two ventrodistal spiniform setae. Carpus as long as merus, with one dorsodistal simple seta in inner region. Propodus slightly longer than carpus, with two ventrodistal spiniform setae, and dorsodistal serration. Dactylus-unguis 0.65 times as long as propodus, nearly straight. Unguis tiny, 0.15 times as long as dactylus. Pereopod 5 ( Fig. 4E View Fig ) slightly longer than but otherwise similar to pereopod 4, except for basis having one ventral broom seta, and carpus with one additional inner simple seta on dorsodistal margin. Pereopod 6 ( Fig. 4F View Fig ) similar to pereopod 4, except for basis having one dorsal broom seta and propodus with two additional dorsodistal long setae (one of them broken).

Pleopods ( Fig. 4G, H View Fig ) with basal article uniarticulate, naked. Endopod ( Fig. 4G View Fig ) uniarticulate, with one proximal and six plumose setae on outer margin, and one mid-inner plumose seta and one inner subdistal “step-tipped plumose seta” (see Kakui et al., 2010: Fig. 5j View Fig 2 View Fig ). Exopod ( Fig. 4H View Fig ) uniarticulate, longer than endopod, with 19 or 20 outer plumose setae.

Uropod ( Fig. 4I View Fig ) with basal article naked. Endopod article 1 with one simple and two broom setae; article 2 with five simple and two broom setae. Exopod article 1 subequal to endopod article 1 in length, with one simple seta; article 2 with two simple setae.

Variation observed among males: antennular article 3 with three aesthetascs, and pereopod 5 carpus with one dorsodistal simple seta in inner region.

Females. Body ( Fig. 2B, D View Fig ) about 7.1 times as long as wide. Otherwise similar to males, except cephalothorax not strongly dorsoventrally flattened, 0.19 times total body length, about 1.5 times as long as wide.

Antennule ( Fig. 5A View Fig ) about 0.8 times cephalothorax length. Article 1 similar to that of male. Article 2 0.35 times article 1 length, with one outer simple and two broom setae in distal region. Article 3 0.65 times article 2 length, with five simple and one broom setae, and one aesthetasc. Antenna ( Fig. 5B View Fig ) length 0.85 times antennule length, similar to that of male.

Labrum ( Fig. 5C View Fig ) uniarticulate, rounded; distal region setulate. Mandibles ( Figs. 5D, d View Fig 1 View Fig , E, 7A, B View Fig ) with molar process well developed, with broad masticatory region bearing several teeth. Left mandible ( Figs. 5D, d View Fig 1 View Fig , 7A View Fig ) incisor with four small and two large teeth; lacinia mobilis with three small and two large teeth. Right mandible ( Figs. 5E View Fig , 7B View Fig ) incisor with two asymmetric teeth. Labium ( Fig. 5F View Fig ) with inner lobe rounded, setulate distally; outer lobe rounded, naked. Maxillule ( Fig. 5G, g View Fig 1 View Fig ) not setulate; palp with two setae at tip. Maxilla ( Fig. 5H View Fig ) subovate, naked. Maxilliped ( Figs. 5I View Fig , 7C View Fig ) bases fused, together ovoid, each with one short ventrodistal simple seta at insertion of palp. Endites fused ( Fig. 7C View Fig ); anterolateral region setulate. Palp article 1 naked; article 2 with one outer and three inner setae in distal region; article 3 with one dorsal and three inner setae; article 4 with one simple and five pinnate setae. Epignath ( Fig. 5J View Fig ) similar to that of male.

Cheliped ( Fig. 5K, k View Fig 1 View Fig ) basis slightly longer than wide, with small free posterior portion, and one outer simple seta. Merus similar to that of male. Carpus similar to that of male but 1.85 times as long as wide. Propodal palm with five inner setae and one row of minute setae at insertion of dactylus. Fixed finger with claw; ventral margin with two simple setae; cutting surface with one proximal and three middle simple setae, and two distal small processes. Dactylus about 1.3 times as long as fixed finger, with one inner proximal seta; cutting surface smooth.

Pereopods ( Fig. 6A–F View Fig ), pleopods ( Fig. 6G View Fig ), and uropod ( Fig. 6H View Fig ) generally similar to those of male.