The Database

A live gap analysis dashboard tracking the molecular barcode coverage of Nigerian coastal and marine biodiversity across all major taxonomic groups. Updated as new sequences are generated and deposited.

Changelog Version history & audit trail v20 – v21 Β· click to expand
v21 Β· Apr 2026
β˜… Classification rule rewritten β€” v20's WA β‰₯50% of global ratio retired. Now uses marker-specific absolute WA thresholds: COI β‰₯5 Β· 12S β‰₯3 Β· 18S β‰₯1 Β· 28S β‰₯1 Β· rbcL β‰₯3.
⚠ WA-zero = absent β€” zero West African records now always classifies as Absent, regardless of global count. Affects all turtles, cetaceans, and several deep-water species.
Δ 3 reclassifications — Sardinella maderensis present→partial; Rhizoprionodon acutus and Penaeus notialis partial→absent.
⚑ Decision flowchart redrawn; all PRESENT / PARTIAL / ABSENT definitions and statistics copy updated to match.
v20 Β· Apr 2026
β˜… Priority Sequencing Targets leaderboard added to Statistics β€” weighted composite score (absence + IUCN + ecological priority), CSV export.
+ IUCN Γ— coverage crosstab β€” threatened taxa (VU/EN/CR) cross-tabulated against reference coverage.
+ Classification decision tree (flowchart) first added; updated in v21.
⌨ Keyboard shortcuts: ⌘K / Ctrl+K or / to focus search.
πŸ› Fixed duplicate scripts, broken email placeholders, and duplicate UI elements.

Why coverage matters

Every species in the "absent" column could represent a false negative in any eDNA metabarcoding study conducted in Nigerian waters. The animal or plant may be present, its DNA may be in your sample, and your PCR may amplify it perfectly β€” but without a matching reference barcode, your analysis software returns nothing. This dashboard makes the scale of that problem visible and actionable.

Gulf of Guinea endemics β€” priority targets

Pteroscion peli (boe drum), Lutjanus goreensis (Gorean snapper), Scomberomorus tritor (West African Spanish mackerel), and Strombus latus (West African stromb) are among several species with zero sequences anywhere in global databases. Each represents a publishable first-barcode contribution. Tympanotonos fuscatus β€” the most commercially important macroinvertebrate in the Niger Delta β€” has partial global coverage but zero Nigeria-specific records.

Current coverage statistics
β€”
Total taxa assessed
β€”
Have sequences
β€”
Priority gaps (absent)
β€”
Partial coverage
β€”
genera tracked
Nematodes
What is in this database

Taxonomic groups covered

  • Fish (estuarine + coastal) β€” 16 priority species, 12S rRNA marker
  • Elasmobranchs β€” sharks and rays of the Nigerian coast
  • Marine pelagic fish β€” tuna, mackerel, swordfish, billfish
  • Marine demersal fish β€” offshore snappers, groupers, dentex
  • Coral reef and hard substrate β€” corals, sea urchins, holothurians
  • Macrobenthos β€” Tympanotonos, Pachymelania, bivalves, polychaetes, mangrove crabs
  • Nematodes β€” 25 genera across 8 orders, 18S + 28S
  • Meiofauna β€” copepods, ostracods, foraminifera
  • Seagrass & macroalgae β€” including Sargassum bloom species
  • Marine mammals β€” including African manatee, Atlantic humpback dolphin
  • Sea turtles β€” all three nesting species

How to use this database

The Gap Analysis tab gives an overview of sequence coverage across all taxonomic groups. Click any stat card or group card to filter the full species list.

The All Taxa tab shows every species in one searchable, sortable table with filters by group, marker, status, and priority. Use the search bar at the top of the page to find any species instantly.

The dedicated Marine Species, Macrobenthos, and Nematodes tabs each provide deeper views of their groups with group-specific filters and ecological context.

All data can be exported as CSV from each tab for use in your own analysis or grant proposal.

Cite this database

Odedere, A.O. (2026). Nigerian Marine Biodiversity Reference Library: A molecular reference framework for the coastal and marine biodiversity of the Gulf of Guinea. Available at: EnviroBiotics.org [accessed 30 March 2026]. doi:10.5281/zenodo.19201628

πŸ“¦ Zenodo DOI GitHub Repository
πŸ“Š Data Sources β€” How Coverage Is Determined
Classification decision tree
Applied to every species at render time β€” no manual classification
Coverage classification decision tree Query species NCBI + BOLD + SILVA (WA filter) Any West African NCBI records? (WA_NCBI β‰₯ 1) No βœ— ABSENT No regional reference Yes WA records meet marker threshold? (COIβ‰₯5 Β· 12Sβ‰₯3 Β· 18Sβ‰₯1) No (below threshold) Yes Records in both NCBI and BOLD? Yes βœ“ PRESENT Reliable regional ID No (one DB only) ~ PARTIAL Regional data insufficient
COI β‰₯5 WA records
Fast-evolving animal barcode
12S β‰₯3 WA records
Vertebrate eDNA marker
18S β‰₯1 WA record
Genus-level, conserved
28S β‰₯1 WA record
Genus-level metazoan
rbcL β‰₯3 WA records
Plants/algae barcode
Worked examples. Sardinella aurita has 4 WA 12S records (β‰₯3, meets threshold) and BOLD WA records confirmed β€” overall present. Drepane africana has 2 WA 12S records (below the threshold of 3) β€” partial, more regional barcodes needed. Tursiops truncatus has 42 global COI records but zero West African records β€” NCBI is absent for the regional library regardless of global abundance; BOLD WA-present keeps overall status partial. This is the key shift from v20: global coverage no longer rescues a species with zero regional sequences.
βœ“ PRESENT Qualifying barcodes in both NCBI and BOLD/SILVA, with WA records meeting the marker threshold (COI β‰₯5, 12S β‰₯3, 18S β‰₯1, 28S β‰₯1, rbcL β‰₯3). Reliably detectable for Nigerian eDNA β€” though Nigeria-specific sequences remain preferred.
~ PARTIAL WA records exist but fall below the marker threshold, or sequences exist in only one database. Identification possible but not robust β€” more regional barcodes needed.
βœ— ABSENT Zero West African records in both NCBI and BOLD/SILVA. No regional reference sequence exists for this taxon β€” undetectable in Nigerian eDNA surveys regardless of global availability. Highest priority for new voucher collection and barcoding.

Coverage status is derived by cross-referencing each taxon against the following 10 global databases. A taxon is classified present when qualifying barcodes exist in both NCBI and BOLD/SILVA with West African records meeting the marker-specific threshold (COI β‰₯5, 12S β‰₯3, 18S β‰₯1, 28S β‰₯1, rbcL β‰₯3); partial when WA records exist but fall below the marker threshold, or when only one database is covered; and absent when zero WA records exist in both NCBI and BOLD/SILVA. Thresholds reflect the intraspecific variation needed for reliable identification with each marker β€” fast-evolving barcodes like COI require more replicate sequences to capture haplotype diversity, while conserved ribosomal markers (18S, 28S) used for genus-level work are operationally useful with a single well-curated reference. Classification is WA-specific: a taxon with global records but zero West African sequences is an "absent" gap in the regional reference library, regardless of global coverage.

NCBI Nucleotide
Primary sequence database. 12S, COI, 18S, 28S, rbcL queries via Entrez API.
BOLD Systems v5
COI barcode library (v5, 2024+). Geographic filter: Nigeria, Ghana, Cameroon, Benin, Togo, Senegal, Guinea, CΓ΄te d'Ivoire, Liberia.
SILVA SSU rRNA
Most comprehensive 18S rRNA database. Used for nematodes, meiofauna, protists.
WoRMS / FishBase
Taxonomy authority & accepted names. IUCN status and regional checklists.
NeMys / OBIS / GBIF
Nematode taxonomy (NeMys); occurrence records (OBIS/GBIF) for Gulf of Guinea.
AlgaeBase / ENA
Macroalgae & seagrass taxonomy; supplementary sequences via ENA/EMBL.
IUCN Red List
Conservation status for all vertebrates, elasmobranchs, sea turtles, and marine mammals.
Key Insights & Scientific Findings
πŸ”΄ Critical Gaps β€” Zero West African Reference Records
  • All 25 nematode genera tracked β€” 0 Nigeria sequences for all (18S and 28S)
  • Cynoglossus senegalensis (Senegalese tonguesole) β€” zero records, abundant bycatch
  • Gulf of Guinea endemics (Pteroscion peli, Lutjanus goreensis, Lutjanus agennes) β€” zero records globally
  • Tursiops truncatus, Carcharhinus leucas β€” well-barcoded globally (42 and 7 records) but zero West African sequences; undetectable in Nigerian eDNA without regional vouchers
  • Sea turtles (Chelonia mydas, Dermochelys coriacea, Lepidochelys olivacea) β€” nest on Nigerian beaches, zero WA 12S records
  • Penaeus notialis (pink shrimp, largest commercial fishery) β€” 45 global COI but zero WA; major regional gap
  • Sesarma huzardi, Goniopsis pelii, Egeria radiata β€” staple seafood, zero records
  • Strombus latus (West African stromb, endemic) β€” zero records
βœ… Well-Covered Taxa β€” Regional Reference Sufficient
  • Sardinella aurita β€” 4 WA 12S records (meets threshold of 3); BOLD WA confirmed
  • Mugil cephalus (flathead mullet) β€” 27 WA 12S records; cosmopolitan and excellently covered
  • Sphyrna lewini (scalloped hammerhead) β€” 4 WA 12S records meeting threshold (NCBI); BOLD partial keeps overall partial, but NCBI-regional is sufficient
  • Pseudotolithus elongatus (bobo croaker) β€” 3 WA 12S records meets threshold in NCBI; BOLD absent β†’ overall partial but NCBI-regional is sufficient
Note: "well-covered" here means the WA reference library is sufficient for that marker β€” not that the species is abundantly studied worldwide.
⚠️ Partial Coverage β€” Regional Data Below Threshold
  • Ethmalosa fimbriata (bonga shad, #1 commercial pelagic) β€” 2 WA 12S records, below threshold of 3; BOLD absent
  • Sardinella maderensis β€” 2 WA 12S records (below threshold); BOLD WA confirmed
  • Pseudotolithus senegalensis (cassava croaker) β€” 2 WA 12S records (below threshold); BOLD absent
  • Drepane africana (African sicklefish) β€” 2 WA 12S records (below threshold of 3); BOLD absent
  • Polydactylus quadrifilis, Galeoides decadactylus, Elops lacerta β€” 1–2 WA 12S records each; below threshold
  • Arius latiscutatus (rough-head sea catfish) β€” 2 WA 12S records; below threshold
  • Callinectes amnicola (Lagos lagoon swimming crab) β€” 1 WA COI record; below threshold of 5
  • Macrobrachium vollenhovenii (African river prawn) β€” 1 WA COI record; below threshold
  • Tympanotonos fuscatus (Niger Delta periwinkle) β€” NCBI partial; zero Nigeria-specific
πŸ“Š Data Interpretation & Integrity Notes
  • Classification is regional: "present" means West African records meet the marker threshold β€” not global availability
  • Zero WA = absent, regardless of how well-studied the species is globally (major shift from v20)
  • Nematode 0 values are real β€” NCBI, BOLD, and SILVA all return zero Nigeria/WA records
  • SILVA is more complete than NCBI for 18S nematode sequences
  • IUCN statuses sourced from IUCN Red List (2024); subject to revision
  • Dashboard v21 β€” run Python scripts locally to update with live database counts
Marker gene guide

12S rRNA  Fish and vertebrates

The MiFish universal primer set (MiFish-U/E) amplifies a ~170bp region of the 12S ribosomal RNA gene. It is the global standard for fish eDNA metabarcoding β€” highly sensitive, works from both water-column eDNA and tissue extracts, and directly comparable to thousands of published datasets.

COI  Animals and invertebrates

Cytochrome oxidase I is the universal animal barcode β€” the primary marker of the BOLD Systems database. The Leray-XT primers amplify a ~313bp region suitable for metabarcoding. Used here for macrobenthos (gastropods, bivalves, polychaetes, crabs), marine invertebrates, and marine mammals.

18S rRNA  Meiofauna and protists

The V1V2 hypervariable region of the 18S small subunit ribosomal RNA gene is the primary marker for meiofauna metabarcoding. Primers NF1 / 18Sr2b amplify across free-living nematodes, copepods, and protists. Sequences are classified against the SILVA SSU reference database.

Emerging priorities

Sargassum bloom monitoring

Since 2011, catastrophic Sargassum inundations have struck Nigerian coastal waters annually. Two species dominate: Sargassum natans and S. fluitans. Having rbcL reference sequences from Gulf of Guinea populations enables eDNA-based early warning detection β€” tracking bloom approach before physical landfall β€” and source attribution studies to understand whether bloom material originates from the open Atlantic or local coastal populations. This is an active monitoring need for NMBL.

Niger Delta sediment eDNA

Sediment eDNA from the Niger Delta captures the meiofaunal community β€” principally free-living nematodes β€” whose composition changes measurably and predictably under hydrocarbon contamination. The nematode-to-copepod (N:C) ratio is a well-validated pollution index. With a West African nematode reference library, these indices can be computed from eDNA data rather than requiring time-consuming microscopy β€” transforming Niger Delta pollution monitoring for regulators, oil companies, and community stakeholders alike.

Offshore EEZ biodiversity

Nigeria's ~210,000 kmΒ² EEZ remains almost entirely uncharacterised at the molecular level. Gulf of Guinea endemic fish species β€” demersal groupers, snappers, croakers unique to this ecosystem β€” have never been barcoded. As Nigeria expands its Blue Economy policy framework and deepwater oil operations, baseline molecular biodiversity data for the EEZ becomes essential for impact assessment, fisheries management, and international reporting under the Kunming-Montreal Global Biodiversity Framework.

Data deposition and access

Public repositories

All sequences generated by this project are deposited in: BOLD Systems (project NGMBL β€” Nigerian Marine Biodiversity Reference Library), NCBI GenBank with full voucher metadata, and SILVA (for 18S sequences). All deposits are open access with no embargo.

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