Notobathynella pentatrichion, Camacho & Hancock, 2010

Camacho, A. I. & Hancock, P., 2010, First record of Syncarida from Queensland, Australia, with description of two new species of Notobathynella Schminke, 1973 (Crustacea, Bathynellacea, Parabathynellidae), Journal of Natural History 45 (1 - 2), pp. 113-135 : 124-131

publication ID	https://doi.org/ 10.1080/00222933.2010.520824
persistent identifier	https://treatment.plazi.org/id/FA578792-265D-C71E-FE26-37AEFEEDFA09
treatment provided by	Felipe
scientific name	Notobathynella pentatrichion
status	sp. nov.

Treatment

Notobathynella pentatrichion sp. nov.

( Figures 4–6 View Figure 4 View Figure 5 View Figure 6 )

Material examined

Type locality. Department of Natural Resources monitoring piezometer number 13700234A, 19 May 2004 from alluvial aquifer of Yellow Waterholes Creek near Bundaberg, Queensland, Australia; nine males and six females were collected.

Other localities. Department of Natural Resources monitoring piezometer number 13700067, 20 May 2004, alluvial aquifer of Elliott River near Bundaberg, Queensland, Australia ; five males and three females were collected, and piezometer number 13710036, 16 May 2004, from the alluvial aquifer of Gregory River near Bundaberg, Queensland, Australia ; one male, two females and one juvenile were collected.

The details of the description are based on all specimens. The holotype is a male and the allotype is a female and the type series contains 20 additional specimens (12 males and eight females): holotype MNCN20.04 About MNCN / 8232, allotype MNCN20.04 About MNCN / 8233 and type series MNCN20.04 About MNCN / 8234.

Description

Body. 1.33 mm long for the holotype (male) and 1.78 mm long for the allotype (female). Largest male total length 2.06 mm, smallest 1.33 mm; largest female total length 2.33 mm, smallest 1.30 mm. Body elongated, segments slightly widening towards posterior end; approximately 8.5 times long as it is wide. Head 1.2 times as long as it is wide. Pleotelson with one small barbed ventral seta on either side.

Antennule ( Figure 4A View Figure 4 ). Seven-segmented; no sexual dimorphism; length of first three segments 1.1 times as long as last four segments; segment seven slightly shorter than segment six; inner flagellum almost trapezoidal; fourth and fifth segments similar in size; setation as in Figure 4A View Figure 4 ; segment three with four setae; segment five with two setae, and six and seven with three terminal aesthetascs.

Antenna ( Figure 4B View Figure 4 ). Five-segmented; long and curved backwards, half the length of the antennule; two first segments shortest, third segment twice as long as second, and last two segments similar in size, the last a bit longer than the previous one and with four setae, one of which is plumose. Setal formula: 0 / 0 / 1+0 / 1+1 / 4(1).

Labrum ( Figure 4C View Figure 4 ). Almost flat, with eight main teeth, and seven lateral teeth at either side. Ventral surface with several rows of fine spinules and four tooth-like protusions on both sides.

Labrum female ( Figure 4D View Figure 4 ). Almost flat, with eight main teeth, and eight lateral teeth at either end. Ventral surface with several rows of fine spinules and with five tooth-like protusions on both sides.

Mandible ( Figure 4E View Figure 4 ). Pars incisiva having four well-developed teeth and triangular small proximal tooth; pars molaris with seven claws, five distal with small spines and two small joined proximal claws with a large number of fine hairs; the distal seta of the mandibular palp almost exceeds pars incisiva in length.

Mandible female. Pars incisiva similar to the holotype; pars molaris with eight claws, six being strong, the distal with small spines and two small joined proximal claws with a large number of fine hairs.

Maxillule ( Figure 4F View Figure 4 ). Proximal endite with four long serrulate claws; distal endite with seven claws, two smooth, one apical and other subapical, other five with denticles and fine long setules at the base and three subterminal smooth setae on outer distal margin.

(frontal view); (F) thoracopod VIII female (lateral view); (G) uropod (latero-external view); (H) pleotelson and furcal rami (dorsal view); (I) endopod of uropod female allotype (latero-external view). Scale bar in mm. Abbreviations: D. Lb, dentate lobe; I. Lb, inner lobe; O. Lb, outer lobe; Bsp, basipod; Endp, endopod; Exp, exopod.

Maxilla ( Figure 4G View Figure 4 ). Four-segmented, segment three elongated and fourth small; setal formula 3, 4+1, 14, 6.

Thoracopod I–VII ( Figure 5A–G View Figure 5 ). Well developed, length gradually increasing from I to IV, last four similar in size; epipod on I to VII small, measuring half the length of basipod; basipod with one smooth seta at distal inner corner in all Th. Exopod shorter than endopod on Th I, II and VII and similar on Th III to VI and with the following numbers of segments: 1-3-3-4-4-3-3; each segment with two barbed setae (with one group of ctenidia at the base of inner setae) except last segment that has a plumose outer seta in Th I to VI but is barbed and very short in the Th VII; endopod foursegmented, first segment is small, second and third long and similar in length, and fourth is small (with two smooth similar strong claws and two smooth setae), all inner setae on segments smooth and outer setae of first and second segment of Th I to VII are plumose. Setal formula: Th I, 3+1 / 3+1 / 2+1 / 4(2); Th II, 1+1 / 3+2 / 1+1 / 4(2); Th III, 1+1 / 2+2 / 0+1 / 4(2); Th IV-VI, 1+1 / 2+1 / 1+1 / 4(2); Th VII, 1+1 / 2+1 / 0+1 / 4(2).

Allotype female exopod shorter than endopod on Th I to III and VII and similar on Th IV to VI and with the following numbers of segments: 2-3-4-4-5-4-3. Setal formula of the endopods of thoracopods: Th I, 3+1 / 3+1 / 2+1 / 4(2); Th II, 2+1 / 3+2 / 1+1 / 5(3); Th III, 1+1 / 3+2 / 1+1 / 5(3); Th IV, 1+1 / 3+2 / 1+1 / 5(3); Th V, 1+1 / 3+2 / 1+1 / 4(2); Th VI, 1+1 / 3+1 / 1+1 / 4(2); Th VII, 1+1 / 2+1 / 1+1 / 4(2).

Thoracopod VIII male ( Figure 6A–D View Figure 6 ). Rectangular; basal region of the penial complex supports three lobes: inner lobe (I. Lb.), outer lobe (O. Lb.) and dentate lobe (D. Lb.); subtriangular inner lobe; outer lobe, inner lobe and dentate lobe of similar length, and they do not exceed the end of the external side of basipod (Bsp); dentate lobe has many denticles; endopod (Endp.) long, almost three times longer than exopod with two smooth terminal setae; exopod (Exp.) small and with one tooth; basipod trapezoidal in the external face, well-developed, in the internal side with a seta above its outer distal corner and with a crest-like protuberance.

Thoracopod VIII female ( Figure 6E,F View Figure 6 ). Small, rounded with one segment with one small tooth.

First pleopods. Absent.

Uropod ( Figure 6G View Figure 6 ). Sympod slender, five times as long as wide, bearing eight barbed spines of similar size, and one distal spine three times longer than others; 2.4 times longer than endopod and 1.7 times longer than exopod; endopod shorter than exopod, with two spinous processes on the inner margin and one strong spine on the distal part, two plumose setae near the inner margin, one basal and one subterminal, that exceed the distal end of endopod, and two barbed terminal setae of different length; exopod four times as long as wide and has five barbed setae.

Uropod female. Sympod with eight barbed spines of similar size, and a distal spine three times longer than the others; endopod ( Figure 6I View Figure 6 ) shorter than exopod, with one small spine and one robust spine on the distal part, two plumose setae near the inner margin, one basal and one subterminal, that exceed the distal end of endopod, and two barbed terminal setae of different length.

Pleotelson ( Figure 6H View Figure 6 ). With one small, plumose ventral seta on either side near the base of the furca. Anal operculum convex and distinctly protruded.

Furca ( Figure 6G View Figure 6 ). Rectangular, twice as long as wide, with 10–11 barbed spines (the two terminal ones longer and thicker); two unequal dorsal plumose setae, that do not exceed the distal part of terminal spines; with a smal lateral furcal organ.

Variability

There is variation in the number of spines on the furca (nine to 11), on sympod of uropod (eight to 11), and on endopod of uropod (one to five). There is also variation in the number of exopodal segments of Th I–VII (1,3 −3,4 −3,4 −3,4 −3,5 −3,4 −3,4) and the number of setae on different segments of the endopods of some thoracopods of males and females. Setal formula: Th I, 2,3+1 / 2,3+1 / 2+1 / 4(2); Th II, 1,2+1 / 2,3+1 / 1+1 / 4,5(2,3); Th III, IV, 1+1 / 2,3+1,2 / 1+1 / 4,5(2,3); Th V, 1+1 / 2,3+ 1,2 / 0,1+1 / 4(2); Th VI, 1+1 / 1,3+1 / 0,1+1 / 4(2); Th VII, 1+1 / 1,2+1 / 0,1+1 / 4(2).

Etymology

The species name, “ pentatrichion ” (substantive in apposition) refers to the five setae on the exopod of the uropod.

Remarks

Notobathynella pentatrichion sp. nov. does not have unique characters within the family, but is the first species of the genus with five setae on the exopod of the uropod. As with N. octocamura sp. nov., N. pentatrichion sp. nov. has three segments in the exopod of the thoracopod I, five segments in the exopod of thoracopod V (see Table 2) and three setae and two claws in the last segment of the endopod of thoracopods II to IV (see Table 3). All of these particular characters, considered together with a unique combination of others (see Table 2 and 3) leave no doubt that the studied specimens belong to a new species.

The nearest (geographically) known species to Bundaberg is N. remota Schminke, 1973 , but this has six segments on A.II. In contrast, the new species has five, which is the dominant case in the genus. Notobathynella pentatrichion sp. nov. seems more similar to species from New Zealand ( N. hineoneae , N. chiltoni Schminke, 1973 ) and N. octocamura sp. nov. (described above) than to N. remota (New South Wales).