| Haplognathia asymmetrica Sterrer, 1991b | 18 Apr 1991 | 1 m | muddy sand betwwen Thalassia and Halimeda | sample 91.20: between two mangrove cays |
| Haplognathia ruberrima (Sterrer, 1966) | 18 Apr 1991 | 1 m | muddy sand betwwen Thalassia and Halimeda | sample 91.20: between two mangrove cays |
| Labidognathia longicollis Riedl, 1970a | 18 Apr 1991 | 1 m | muddy sand betwwen Thalassia and Halimeda | sample 91.20: between two mangrove cays |
| Gnathostomula peregrina Kirsteuer, 1969a | 18 Apr 1991 | 1 m | muddy sand betwwen Thalassia and Halimeda | sample 91.20: between two mangrove cays |
| Austrognathia microconulifera Farris, 1977 | 18 Apr 1991 | 1 m | muddy sand betwwen Thalassia and Halimeda | sample 91.20: between two mangrove cays |