Tumidochelia tuberculata, Larsen, Kim, 2011

Larsen, Kim, 2011, Tanaidaceans (Crustacea) from the Central Pacific Manganese Nodule Province. I. The genera Collettea, Robustochelia and Tumidochelia, ZooKeys 87, pp. 19-41 : 26-30

Tumidochelia tuberculata sp. n. Figs 57

Material examined.

Holotype, non-ovigerous female (MNHN-Ta1031), Station CAROT-0 # 15, 04/06-2004, 14°02.8654'N, 130°05.3508'W, depth 5044 m.

Diagnosis.

Female. Pereonites 2-4 longer than wide. Pleotelson longer than combined length of four pleonites. Antenna with six articles (+ fusion line), article 4 longer than other articles, with clear fusion line. Cheliped propodus with large paired dorsal tubercles near dactylus insertion. Pereopod 1 merus and carpus with long (longer than length of merus) robust setae.

Male. Unknown.

Etymology.

The species is named after the diagnostic character of the tubercles on the cheliped propodus.

Description.

Female(body and appendages of holotype).

Body (Fig. 5A, B). Body length 2.0 mm. Subcylindrical, elongate, approximately 8.5 times longer than wide. Lateral edges almost completely straight.

Cephalothorax longer than wide (l/w 1.5). Eyes and eye-lobes absent.

Pereon. Pereonites 1 and 6 wider than long. Other pereonites longer than wide, pereonites 3 longest.

Pleonites all wider than long, subequal, bearing pleopods.

Pleotelson longer than combined length of four pleonites.

Antennule (Fig. 6A) with four articles. Stout at base- tapering distally, almost as long as carapace. Article 1 with one simple distal seta and three subdistal setulated setae; article 2 approximately 0.80 times as long as article 1, with two simple and three setulated distal setae; article 3 approximately 0.3 times length of article 2, with two simple distal setae; article 4 approximately twice length of article 3, with four long and one short simple distal setae and one prominent aesthetasc.

Antenna (Fig. 6B) approximately 0.7 times as long as antennule. Article 1 naked and fused to cephalon. Article 2 wider than other articles, with dorsodistal process and one stout dorsodistal seta. Article 3 band-shaped, with one dorsodistal seta, Article 4 longer than other articles, with clear fusion line, with one medial (distal on first article component) setulose seta, with two long and one short simple setae distally and with one subdistal setulated setae. Article 5 with one simple distal seta. Article 6 approximately 0.25 length of article 5, with three simple distal setae and one aesthetasc.

Mouthparts:Relatively small compared to body size (mandibular body less than 0.1 mm, see remarks). Labrum (Fig. 6C) apex pointed, apparently naked. Mandibular molar tapering. Left mandible (Fig. 6D) incisor with three distal denticles; lacinia mobilis blunt with two denticles. Right mandible (Fig. 6E) incisor with two denticles. Labium (Fig. 6F) with one pair of lobes, without setules or process. Maxillule (Fig. 6G) endite with nine terminal spiniform setae of which two are serrated; palp with two terminal setae. Maxilla (Fig. 6H) narrow and long (as long as maxillule endite), featureless. Maxilliped (Fig. 6I) endites with blunt distal process and small outer seta, fairly wide (almost as wide as basis) and long (reaching palp article 4). Basis fused. Palp article 1 naked; article 2 with two inner setae and one outer seta; article 3 with three inner setae; article 4 with four setae. Epignath not recovered.

Cheliped (Fig. 7A) attached to cephalothorax by a large sclerite. Basis naked, narrow in posterior part, approximately as long as carpus. Merus with one ventral seta. Carpus widening distally, with two small dorsal setae and two simple ventromedial setae, ventrodistal part inflated into a large carpal shield, extending distally past propodus articulation. Propodus as long as basis, with two simple (thick) ventral setae mid-length and three (one longer than the other two) inner setae proximal to dactylus insertion, with paired dorsal crest next to dactylus insertion. Fixed finger with three inner setae and three blunt denticles. Dactylus as long as fixed finger

Pereopod 1 (Fig. 7B) longer than other pereopods. Coxa naked. Basis robust without seta. Ischium with one simple distal seta; merus widening distally, longer than carpus, with one ventrodistal, long (longer than merus) bayonet-shaped setae. Carpus rectangular, half as long as propodus, with two long (longer than merus) bayonet-shaped distal setae. Propodus elongate, longer than merus, with one spiniform ventro-subdistal seta and dorsal spine. Dactylus and unguis combined shorter than propodus, dactylus with distal spine at unguis insertion. Unguis as long as dactylus.

Pereopod 2 (Fig. 7C) as pereopod 1 except it is smaller; carpus with three long setae; dactylus without spine.

Pereopod 3 (Fig. 7D) as pereopod 2 except: carpus with two setae.

Pereopod 4 (Fig. 7E) coxa absent. Basis with two medial setulated setae on both margins (the ventral ones much the larger). Merus with two short spiniform ventral setae. Carpus with three spiniform ventral setae and one bone-shaped seta. Propodus with four spiniform distal setae. Dactylus (including unguis) as long as propodus, with ventral serration; unguis less than 0.3 times as long as dactylus.

Pereopod 5 (Fig. 7F) as pereopod 4 except: basis with only one dorsal setulated seta. Ischium apparently naked.

Pereopod 6 (Fig. 7G) as pereopod 4 except: basis with only one ventral setulated seta. Propodus, with six distal setae.

Pleopods (Fig. 7H). Basal article with one plumose seta. Endopod rectangular, with numerous simple distal setae. Exopod rectangular, with one robust proximal seta, and numerous simple distal setae.

Uropod (Fig. 7I) biramous, basal article naked, with dorsomedial spiniform process. Endopod with two subequal articles; article 1 with three simple distal setae; article 2 with one long simple subdistal seta, three long and two short simple distal setae. Exopod reaching beyond midlenght of first endopod article, with two subequal articles; article 1 naked, article 2 with two simple but unequally length distal setae.

Remarks.

Tumidochelia tuberculata can be separated from Tumidochelia uncinata by the cheliped propodus having paired dorsal crest next to dactylus insertion; from Tumidochelia dentifera by the pleotelson being longer than last three pleonites combined; from Tumidochelia randyi by the pereonite 2 being longer than other pereonites; from the only other Pacific species, Tumidochelia knighti , by the straight lateral margins (with no segment indentations), the longer pleotelson, the antenular fusion line, the cheliped propodus tubercles, and a longer uropodal exopod.

Key to the species of Tumidochelia, females