Phoxokalliapseudes gobinae (Bamber, 1999)

Bamber, Roger N., 2013, Tanaidaceans from Brunei, IV. The Families Kalliapseudidae, Pagurapseudopsidae, Parapseudidae and Apseudidae (Crustacea: Peracarida: Tanaidacea: Apseudomorpha), with descriptions of a new genus and six new species, Zootaxa 3734 (4), pp. 401-441 : 406-407

Phoxokalliapseudes gobinae (Bamber, 1999)

Kalliapseudes (Kalliapseudes) gobinae Bamber 1999 , 181–184, figs 8–9. Bamber & Sheader 2005, 287 (partim). Phoxokalliapseudes gobinae Drumm & Heard 2011, 38–43, figs 22–24. Bamber et al. 2012, 87.

Material: 1♂, Sample BU3; 2♀♀ (one with oostegites), Sample B12; 2♀♀ (one brooding), Sample B13; all Station B, 04°51′06"N 114°35′26"E, 20 m depth, sand. 5♂♂, 4 brooding ♀♀, 9 neuters, sample DA1; 2♂♂, 2♀♀ (one brooding), sample DA2; both Station DA, 05°54′28.5"N 114°38′23.3"E, 20 m depth, sand.

6♀♀, 1 neuter, Station S14, 04°42′39"N 114°26′24.6"E, 12.7 m depth, sand. 3♀♀, Station S18, 04°41′30"N 114°27′13.5"E, 7.5 m depth, sand. 1♀, Station S17, 04°41′13"N 114°27′23"E, 6.5 m depth, sand. All coll. March 2009.

2 specimens, 05°21′25"N 111°26′30"E; 1 specimen, 05°21′08"N 111°26′25"; 4 specimens, 05°20′58"N 111°26′15"E; 1 juvenile, 1 manca, 05°20′53"N 111°26′21"E; 3♀♀ (1 brooding), 1 subadult ♂, 1♂, 2 juveniles, 05°20′17"N 111°27′06"E. All ca 90 m depth, coll. September 2009.

1 specimen, 05°22′10"N 111°27′00"E; 2 specimens, 05°21′51"N 111°27′18"E; 3 specimens, 05°21′59"N 111°27′07"E; 2♀♀, 05°22′14"N 111°27′04"E; 3 specimens, 05°22′02"N 111°26′52"E; 3 specimens, 05°22′14"N 111°26′52"E; 1 specimen, 05°21′56"N 111°27′22"E; 3 specimens, 05°21′44"N 111°27′22"E; 2 specimens, 05°21′44"N 111°27′11"E; 5 specimens, 05°22′21"N 11°27′30"E; 1♀, 1 juvenile, 05°22′44"N 111°27′52"E; 4 specimens, 05°20′17"N 111°27′06"E; 1 specimen, 05°22′42"N 111°28′46"E. All ca 70 m depth, coll. March 2012.

Remarks: Phoxokalliapseudes gobinae is relatively widespread off the South China Sea coasts of Brunei and Sabah (Bamber 1999; Bamber & Sheader 2005), in the latter case sympatric with Kalliapseudes bamberi Drumm & Heard, 2011, and is a dominant member of the macrobenthos (see Introduction). The present material extends its known depth range to from 6.5 to 90 m.

As this species was relatively common, all the samples were analyzed for their population structure, along with data from the type collection (Bamber 1999), collected at 60 m off Brunei.

At 20 to 90 m, densities were 7–11 individuals m -2. Densities in shallower-water samples were sparser, ranging from zero to 4 individuals m -2.

Males and breeding females (females with either oostegites or brood pouches) were absent at stations shallower than 20 m. The male:female sex ratio at depths from 20 to 90 m ranged from 0.7 to 1.1, not significantly different from 1:1. Bamber et al. (2009) found a 1:1 sex ratio in Cristapseudes omercooperi (Larwood, 1954) in the Eastern Mediterranean; conversely, BłaŻewicz-Paszkowycz & Bamber (2012) found a male:female ratio of 0.4 for Kalliapseudes obtusifrons (Haswell, 1882) in the Bass Strait, Australia.

Analysis of the variance and mean of sample densities was used to determine the common dispersion parameter (k) of the negative binomial distribution [k = m 2/(s 2- m), where m is the mean and s 2 the variance]. The densest populations, at 20 m depth, showed a highly aggregated distribution (k = 0.22; 1/ k>0); populations shallower than 20 m showed an even distribution (k = -0.3 to -0.4; 1/ k <0), albeit based on sparse data; populations deeper than 20 m showed a random distribution (k = -1.4 to -2.5; 1/ k ≈0).

Bamber & Marshall (in press) discussed the instability of the shallower inshore seabed off Brunei, which was attributed to physical disturbance from wave action, probably coupled with a greater input of organic matter below the wave-base. Total tanaidacean densities from 2 to 13 m depth were between one half and one-quarter of the average at 20 m depth. Phoxokalliapseudes gobinae thus appears to be widespread and breeding at depths from 20 m and deeper, while its occurrence in the less stable sediments in shallower waters is sparser, involving nonreproductive individuals.