Koremasphaera colonus, Bruce, 2003

Bruce, N. L., 2003, New genera and species of sphaeromatid isopod crustaceans from Australian marine coastal waters, Memoirs of Museum Victoria 60 (2), pp. 309-369 : 340-345

publication ID	https://doi.org/ 10.24199/j.mmv.2003.60.28
DOI	https://doi.org/10.5281/zenodo.12210650
persistent identifier	https://treatment.plazi.org/id/038D87F1-FFCE-FFD2-FCD8-FA234521FA40
treatment provided by	Felipe
scientific name	Koremasphaera colonus
status	sp. nov.

Treatment

Koremasphaera colonus View in CoL sp. nov.

Figures 23–27 View Figure 23 View Figure 24 View Figure 25 View Figure 26 View Figure 27

Material examined. Holotype. Male (7.5 mm), “The Whaleback” bommie, 0.5 km S of Point Hicks, Vic., 37°48.5´S, 149°16.8´E, 8 Apr 1989, sponge/yellow zoanthid community in roof of cave, 13 m, G.C.B. Poore and R. S. Wilson ( NMV J39723 About NMV ). GoogleMaps

Paratypes. Female (non-ovigerous 11.5 mm), 5 immature (4.5–5.5 mm), 36 mancas (2.3–2.6 mm), same data as holotype ( NMV J26403 About NMV ) GoogleMaps .

Description of male. Body twice as long as greatest width, lateral margins subparallel, widest at pereonite 5; dorsal surfaces of pereon, pleon and pleotelson densely setose, pereonites 6 and 7, pleon and pleotelson with small cuticular spikes. Head anterior margin without transverse ridges, rostral process visible in dorsal view, overlapping epistome ventrally; head about half as long as pereonite 1 in dorsal view; pereonite 1 dorsally smooth, pereonites 2–7 posteriorly with raised setose ridge, postero-ventral angles of coxae 5–7 produced to acute point, pereonite 1 about 1.5 times as long as pereonite 2; pereonite 2>3>4<5>6>7. Pleon laterally about twice as long as pereonite 7, with evident sutures, without pleonal sublateral ‘keys’. Pleotelson strongly vaulted, posterior margin weakly produced and flat; dorsal surface with 4 indistinct subparallel longitudinal ridges, lateral ridges being shortest.

Antennule peduncle article 1 1.5 times as long as wide, about 1.9 times as long as article 2, anterior margin convex, with submarginal ridge, posterior straight, angled obliquely distally; article 3 about as long as article 1, about 4.1 times as long as wide, 1.7 times as long as article 2; flagellum 8-articled, extending to posterior of pereonite 1, about twice as long article 3. Antenna relatively robust, peduncle articles 1 and 2 short, article 1 quadrate, combined lengths of articles 1 and 2 about equal to that of article 5; article 3 about 0.6 times as long as article 4; articles 4 and 5 subequal in length, articles 3–5 collinear; flagellum stout, about 0.7 times as long as peduncle, extending to middle of margin of pereonite 3, with 6 densely setose articles.

Epistome anteriorly narrowly rounded, posterior surface with transverse row of 4 nodules. Left mandible incisor with 4 cusps, lacinia mobilis with 3 cusps, spine row of 5 curved serrate spines; right mandible with 2 indistinct cusps, spine row of 1 broad-based multidigitate spine and 6 distally serrate spines; molar process round, crushing surface strongly ridged; palp article 1 longest, articles 2 and 3 subequal in length, article 2 distolateral margin with 6 finely biserrate setae; article 3 with 17 biserrate setae, terminal 2 setae being longest. Maxillule lateral lobe with 12 terminally acute RS on gnathal surface, twelfth seta set between these. Maxilla lateral and middle lobes with 11 and 9 curved finely serrate RS respectively, mesial lobe with about 8 serrate and biserrate RS. Maxilliped endite lateral margin strongly convex, distal margin with 3 CP RS at sublateral angle, 2 cactus setae, 6 curved CP RS; distomesial margin with 35 large stout CP RS, increasing in size proximally.

Pereopod 1 basis about twice as long as greatest width, approximately twice as long as propodus; superior margin with few widely-spaced short simple setae, inferior lateral surface with numerous scale-setae; ischium 1.6 times as long as propodus, twice as long as greatest width, superior margin with 1 proximal and 1 distal acute short simple RS; merus about 0.3 times as long as ischium, 0.8 times as long as greatest width, superior distal angle with 3 acute simple RS inferior distal margin with 4 acute RS and 1 simple slender seta; carpus 1.2 times as long as wide, inferior margin 1.2 times as long as merus, distally with 1 biserrate, 4 acute RS and 1 slender seta; propodus 1.9 times as long as greatest width, inferior lateral margin with 5 short acute RS, inferior margin with 2 basally biserrate RS; dactylus 0.7 times as long as propodus, inferior margin with prominent serrate cuticular scales, secondary unguis simple, acute. Pereopods 2 and 3 similar to pereopod 1, less robust. Pereopod 2 basis 2.4 times as long as greatest width, lateral surfaces dense with scales, 1 proximolateral palmate seta; ischium 0.9 times as long as basis, 3 times as long as greatest width, superior margin with 1 proximal and 1 diastral acute short simple RS, inferior margin with 3 widely spaced short simple setae; merus about one-third as long as ischium, superior distal angle with 4 acute RS, inferior margin with 1 short stout acute RS and 1 long simple seta; carpus about as long as merus, anterodistal angle with 5 RS, 2 of which are biserrate, inferodistal margin with 5 acute RS, one of which is biserrate; propodus about half as long as ischium, 1.8 times as long as carpus, superior distal angle with 1 simple and 1 palmate setae, inferior margin with 3 short stout acute RS, distal-most being longest; dactylus 0.5 times as long as propodus. Pereopods 5–7 similar, ischium notably longer than for pereopods 1–3, distal margins of carpus with more and longer RS. Pereopod 7 basis 2.6 times as long as greatest width, inferodistal angle with single simple seta, superior margin with 2 proximal and 2 distal palmate setae, numerous widely spaced small scale-setae; ischium 1.1 times as long as basis, 4.5 times as long as greatest width, superior distal angle with 1 acute RS, merus one-third as long as ischium, superior distal margin with 3 acute RS, inferior margin 3 minute setae and 1 minute RS at distal angle; carpus about as long as merus, anterodistal angle with 5 long acute simple and serrate RS, inferior margin with 2 stout short acute RS, distal angle 3 biserrate RS; propodus 1.4 times as long as carpus, 0.4 times as long as ischium, superior distal angle with 2 palmate seta, inferior margin with 3 short stout acute RS, 1 at mid point, 2 at base of dactylus; dactylus 0.4 as long as propodus.

Pleopod 1 exopod and endopod with c. 32 and 11 PMS respectively, both rami densely setulose; endopod triangular, 0.6 times as long as exopod, 1.3 times as long as greatest width; exopod lateral and distal margins quadrate. Pleopod 2 exopod and endopod with c. 33 and 14 PMS respectively; appendix masculina 10 times as long as wide, slightly wider proximally, distally weakly bent laterally, apex bluntly rounded. Pleopod 3 exopod and endopod with c. 32 and 12 PMS respectively. Pleopod 4 exopod lateral margin with 7 fine simple setae, distal margin with continuous fine setae. Pleopod 5 exopod with distal scale patch large, forming mediodistal lobe, lateral margin with numerous simple setae, distal margins with long scale-setae; endopod with scale-setae on distal margin only. Uropod peduncle and rami densely covered with large distally bifid simple setae, palmate setae and scale-setae.

Female. Body shape generally similar to that of male, but dorsal surfaces lacking large setae, with smaller tubercles than in male, but with a densely pilose appearance from the abundant scale-setae.

Etymology. From Latin colo (dwell, inhabit), in the sense of a colony.

Distribution. Known only from the type locality, off Point Hicks, Vic.; possibly a commensal of sponges.

Remarks. The setose dorsal body surface in combination with the pleotelson posterior margin being entire and subcylindrical terminally acute uropod rami of about equal length all serve to identify the genus and species.