Stenobermuda warooga Song & Bruce

Song, Ji-Hun, Bruce, Niel L. & Min, Gi-Sik, 2018, The first records of Stenobermuda Schultz, 1982 and Tenupedunculus Schultz, 1979 from Australia, with description of two new species from the Great Barrier Reef (Isopoda, Asellota, Stenetriidae), ZooKeys 733, pp. 1-24 : 9-13

Stenobermuda warooga Song & Bruce sp. n. Figs 5, 6, 7, 8

Material examined.

Holotype. ♂ (1.6 mm), Yonge Reef, northern Great Barrier Reef, 14.57302°S, 145.6189°E, 10 September 2010, outer reef slope, coarse sand, 25 m, CReefs stn. LI10-126B (MTQ W32968).

Paratypes.

3 ♂ (1.7 [all appendage dissected], 1.2 [antennula and pleopod 2 dissected], 1.5 mm [pleopod 1 dissected]), same data as holotype (MTQ W52909). 3 ♂ (1.4, 1.5 [dissected], 1.7 mm), High Rock (between Direction Islands and Ribbon Reef No. 10), northern Great Barrier Reef, 14.82462°S, 145.552°E, 6 September 2010, coral rubble, 8 m, CReefs stn. LI10-092A, coll. C. Buxton (MTQ W32917). ♂ (1.2 mm), 14.57302°S, 145.61980°E, Yonge Reef, 10 November 2010, outside; small coral rubble in spur, 20 m CReefs stn LI10-126A (MTQ W52910). ♂ (1.4 mm), Yonge Reef, 14.60681°S, 145.6311°E, 20 February 2009, outer reef front., dead coral, 30 m, coll. CReefs stn LI09-15B Shawn Smith & Julian Caley (MTQ W52911).

Etymology.

The epithet ' warooga ' is an Aboriginal word meaning small child, in reference to the small size of this species; noun in apposition.

Diagnosis

(male). Body (Fig. 5A) lateral margins smooth. Pereonite 4 smallest. Rostrum (Fig. 5B) acute, proximal lateral margin convex. Antennula (Fig. 5C) shorter than cephalon, with three flagellar articles. Antenna (Fig. 5D) shorter than whole body length, with numerous flagellar articles. Maxilliped (Fig. 6D) endite distal margin with three fan setae. Pereopod 1 (Fig. 7A) superodistal and inferodistal margin without process. Uropod (Fig. 5A, G) very short, biramous; exopod shorter than endopod. Pleotelson (Fig. 8G) lateral margins with distinct notch.

Description

(male).Body (Fig. 5A) length 3.6 times maximum width. Cephalon (Fig. 5B) length 0.8 times width, 3.2 times pereonite 1 length; lateral margins straight or very weakly convex, smooth, with one setae; antennal spines acute; lateral spines acute, longer than antennal spines. Rostrum (Fig. 5B) proximal lateral margin convex. Eyes (Fig. 5B) with four ommatidia, pale brown, arranged in circle. Pereonites 1-7 (Fig. 5A) lateral margin smooth, without setae; pereonite 1 length 0.2 times width, 0.8 times pereonite 2 length, width 1.1 times cephalon width; pereonite 5-7 distolateral margin not produced. Coxal plates (Fig. 5A) small, visible dorsally on pereonites 4-6. Pleotelson (Figs 5A, 8G) length 0.9 times width, with distinct notch.

Antennula (Fig. 5C) length 0.7 times cephalon length; article 1 length 1.6 times width, mesial margin with one short penicillate setae, distolateral margin with one large penicillate seta; article 2 length 2.3 times width, distolateral margin with one large penicillate seta; article 4 length 0.5 times width; flagellum with three articles, one aesthetasc per article on distal two articles.

Antenna (Fig. 5D, E, F) length approximately 0.7 times body length; peduncle article 1 length 0.8 times width; article 2 length 0.9 times width, distolateral margin with one long seta; article 3 length 1.3 times width, distomesial margin with one cluster of setae, lateral margin with six setae surrounding squama; each flagellum article with a cluster of four distally projecting setae, the cluster position serially repeating every four articles.

Mandible (Fig. 6A) left spine row with four spines, right spine row with six spines; palp article 1 length 3.5 times width, distolateral margin with one long seta; palp article 2 length 2.7 times width, with row of one short serrate setae; article 3 length 2.8 times width. Maxillula (Fig. 6B) lateral lobe apex with seven serrate RS; mesial lobe apex with three large plumose setae. Maxilla (Fig. 6C) mesial lobe mesial margin with four large plumose setae, apex with four large setulate setae; middle lobe apex with three large setulate setae; lateral lobe apex with four large setulate setae. Maxilliped (Fig. 6D) basis length 2.0 times maximum width, width 0.9 times endite width; endite distal margin with three fan setae, distomesial corner with one triangular RS; epipod length 3.4 times width, width 1.1 times basis width, apex acute, lateral margin evenly convex.

Pereopod 1 (Fig. 7A) basis length 3.2 times width; superior margin with three short setae; submarginal row of short setae.

Pereopod 1 ischium length 1.9 times width; inferior margin with one short seta; distal margin with one short setae; superodistal margin not produced, apex rounded.

Pereopod 1 merus rectangular; merus length 1.4 times width, 0.8 times carpus length, 0.9 times ischium length; inferior margin with two short setae, one long seta; distal margin with no setae; superodistal margin not produced, apex rounded, with two short setae.

Pereopod 1 carpus rectangular; length 2.0 times width, 1.3 times ischium length; distal margin convex; inferior margin clearly defined, and with four stout setae and four long setae; superodistal margin not produced, apex obliquely truncate.

Pereopod 1 propodus robust and narrow; length 1.9 times maximum width, 3.2 times proximal width, 1.3 times ischium length; inferior margin clearly defined, long, 0.7 times propodus length, 0.7 times superior margin length, lightly setose, regularly spaced setae along entire length; superior margin setae absent. Propodal palm (Fig. 7B) width 0.7 times maximum propodus width, slightly oblique; with three large serrate setae and nine long setae. Pereopod 1 dactylus narrow.

Pereopod 1 dactylus convex in mid-section; length 1.9 times width, 1.3 times propodal palm width, 0.8 times propodus distal width (not including process), 0.4 times propodus length; superior margin distal third with four long setae. Distal margin with three serrate setae. Mesial surface not setose.

Pereopod 2 (Fig. 7C) basis medial inferior margin with stiff seta absent; ischium superior margin with stiff setae absent; merus superodistal margin RS absent; carpus superodistal margin with three setae, inferior margin with two flagellated RS (most distal paired with one RS); propodus superodistal margin with three setae, inferior margin with two flagellated RS, inferodistal margin with one flagellated RS.

Pereopod 7 (Fig. 7D) basis inferior margin without stiff setae; carpus inferior margin with two flagellated RS; propodus inferior margin with one flagellated RS, inferodistal margin with one flagellated RS.

Pleopod 1 (Fig. 8A) protopod length 0.7 times width, surface setae present; rami lateral margins with regularly spaced setae along distal half, inferior surface without setae. Pleopod 2 (Fig. 8B) protopod length 1.9 times medial width, basal lobe width 1.4 times medial width, distal lobe distinctly shorter than exopod, distal lobe blunt; endopod length 0.7 times protopod length, without setae; appendix masculina (Fig. 8C) length 1.8 times endopod length, 1.3 times protopod length, widest distally; lateral margin without distal groove; mesial margin without setae; apex with two process and cuticular fan; lateral margin without setae. Pleopod 3 (Fig. 8D) endopod apex with three plumose setae. Pleopod 4 (Fig. 8E) exopod apex with four plumose setae. Pleopod 5 (Fig. 8F) apex with one seta.

Uropod (Fig. 5A, G) very short, length 0.05 times body length, 0.2 times pleotelson length; protopod length 1.4 times width; endopod length 1.5 times protopod length, distal and sub-distal margins with one penicillate setae, distal tip with cluster of elongate setae with maximum length 1.9 times endopod length; exopod length 0.9 times protopod length, 0.6 times endopod length, distal tip with cluster of elongate setae with maximum length 3.6 times exopod length.

Female.

Not known.

Size.

Males 1.2-1.7 mm (mean 1.5 mm, n = 9).

Remarks.

Stenobermuda warooga sp. n. can be identified by the following unique combination characters: small body size of the adult male (<2 mm); rostrum proximal lateral margin with convex margin; pereonite 5 distolateral margin not produced; pereopod 1 propodus narrow, length 1.9 times maximum width (Table 2). The most similar species is S. brucei Kensley & Schotte, 2002, a species also occurring on coral reefs, with regard to external appearance. However, propodus of pereopod 1 is strongly expanded, length 1.1 times maximum width, and proximal lateral margin of rostrum is straight in S. brucei (propodus of pereopod 1 is narrow, length 1.9 times maximum width, and proximal lateral margin of rostrum is convex in S. warooga sp. n.).

Distribution.

Yonge Reef and High Rock, Lizard Island region, northern Great Barrier Reef both outer barrier reefs; at depths of 8-30 m.