Cercamia laamu, Fraser & Bogorodsky & Mal & Alpermann, 2021

Fraser, Thomas H., Bogorodsky, Sergey V., Mal, Ahmad O. & Alpermann, Tilman J., 2021, Review of the cardinalfishes of the genus Cercamia (Percomorpha: Apogonidae) of the Red Sea and Indian Ocean with descriptions of three new species, Zootaxa 5039 (3), pp. 363-394 : 378-380

Cercamia laamu new species

( Figures 11 & 17 , Tables 2 & 3)

Maldivian Cardinalfish

Holotype: WAM P.34839.002, 30.5 mm SL, Maldives, Laamu Atoll, Olhuveli I., 01º49.183’N 73º 24.108’E, MVE- 18-008 , 1–20 m, 22 Feb 2018, M. V. Erdmann.

Paratypes: WAM P.34839.009, 2, 20.9–27.6 mm SL, collected with the holotype ; WAM P.35214-001 ~ 16 mm SL, damaged, Maldives, Laamu Atoll , Olhuveli I., 01º49.183’N 73º24.108’E , MVE 18-008 , 30 m, 23 Feb 2018, M . V. Erdmann .

Non-type Material: Chagos Archipelago: ROM 51368, 1 , 24.0 mm SL, Peros Banhos Atoll, Indian Ocean Isle Fouquet, offshore reef, over drop-off in large cave, 5º27’02.99”S, 71º48’56.99”E, 8 Mar 1979, WE79-058, 43 m, damaged ; ROM 51367, 1 , ~ 16 mm SL, Salomon Atoll, Indian Ocean near pass at the NW end of Isle Anglaise on outer reef top, 5º18’52.99”S, 72º13’54”E, 25 Mar 1979, WE79-097, 25 m, damaged .

Diagnosis. A species of Cercamia with anal-fin spines and rays II,12–13 (usually 13); second dorsal-fin spine and rays I,10; developed gill rakers on upper limb 1, developed gill rakers on lower limb 12–13; body translucent in life without reddish dots or cross hatching; no stellate melanophores on cheek ( Fig. 11 ).

Description. For general body shape see Figure 11A , proportions (as percentages of standard length) for paratypes in parentheses where different: greatest body depth 30.5 (25.6–28.0); head length 35.4 (34.0–35.3); eye diameter 10.8 (10.6–10.9); snout length 7.8 (6.3–7.5); bony interorbital width 7.2 (9.1); upper-jaw length 18.0 (17.2–19.6); caudal-peduncle depth 10.8 (9.8–10.3); caudal-peduncle length 29.8 (23.4–25.7); first dorsal-fin spine length 12.1 (9.0–12.3); second dorsal-fin spine length 12.1 (8.6–10.6); third dorsal-fin spine length 14.4 (8.3); fourth dorsal-fin spine length 9.8 (7.5); spine in second dorsal fin 11.5 (11.4); first anal-fin spine length 2.0 (2.2–3.0); second anal-fin spine length 8.8 (9.0–10.3); pectoral-fin length (left) 27.9 (-); pelvic-fin length 18.1 (8.8–14.4).

Dorsal fin VI–I,10, all segmented rays branched; anal fin II,12–13, all segmented rays branched, last anal-fin ray split to base; pectoral fin with 10 rays on left side, 10 on right side; pelvic fin I,5; principal caudal-fin rays 9+8, upper and lower principal caudal-fin rays unbranched; procurrent rays 8 (7) above, 8 (7) below; caudal fin forked.

Preopercle with two tiny spines on edge at angle and above angle, tiny spine at angle of ridge. Posttemporal with a small spine. Infraorbitals smooth.

Scales variably missing on nape, body and caudal peduncle, those present cycloid; no pored or pitted scales observed on the body; free neuromast locations and patterns unknown on head, body or caudal fin.

First gill arch with 2 (0) rudiments and 1 developed gill raker on upper limb, lower limb with 1 (0) rudiment and 12–13 developed gill rakers. Premaxilla with 2–3 rows of tiny villiform teeth, exposed from anterior tip to near posterior end when mouth closed; dentary with 2 rows of tiny villiform teeth on side, a patch of slightly curved teeth at anterior tip; teeth absent on palatine, vomer (small tooth on each side, two smaller teeth behind right tooth), ectopterygoid, endopteygoid and basihyal.

Life color ( Fig. 11A & C ): Body translucent without cross-hatched reddish outline of scales or red spots but with tiny dark reddish spots aligned on dorsal half of body below the dorsal scale pattern to about level with fifth soft dorsal-fin ray, dark reddish dots below midline on caudal peduncle, and a series of very small dark reddish spots slightly above the anal-fin base; snout, jaws and gular regions reddish orange, head without stellate melanophores; iris golden with blue internal ring, upper part of orbit bright blue; roundish patch of melanophores on posterior half of interorbital area and anteriorly on nape; abdominal region black or brown with melanophores on peritoneum, and with a moderately broad, oblique, whitish band from near anterior vertebrae downward to just anterior to anal-fin fin origin, area postero-dorsally on abdomen along vertebrae blackish; all fins translucent, caudal fin suffused with reddish orange on basal half.

Color in alcohol. Holotype, see Figure 11B in 70% ethanol: body a uniform light tan; abdomen darkish from high concentration of small melanophores associated with the peritoneum; scattered melanophores on posterior interorbit an over part of neurocranium; no stellate melanophores on upper cheek; no melanophores on gular region of lower jaw; fins without color patterns. Paratypes with same preserved coloration.

Etymology. Laamu, in the Dhivehi language, one of the islands making up the Hadhdhunmathee (Haddhunmathi) Atoll where the holotype was collected. A noun in apposition.

Distribution. Known from two localities, from the Maldives and the Chagos Archipelago.

Remarks. The two small specimens from Chagos Archipelago are not treated as paratypes because of their damaged condition. The 24 mm SL specimen has tiny melanophores on the chin and none on the cheek, 12 analfin rays, 10 soft dorsal-fin rays and 14 developed gill rakers. The 16 mm SL specimen is severely damaged and no complete counts could be made. We identify both specimens as C. laamu based on the 24 mm specimen.

Cercamia laamu differs from congeners in having a higher number of rays in the second dorsal fin (10 versus 9 rays in other species, rarely 10 in C. eremia ), in lacking reddish dots and crosshatching on body, and in lacking stellate melanophores on cheek. In the phylogenetic analysis, the lineage of the single specimen of C. laamu is the sister to the clade containing all residual members of the genus (with exception of Cercamia sp. 4 ), from which it is highly divergent (see Fig. 5 ).

Figures

FIGURE 5. Maximum likelihood phylogeny of partial mitochondrial cytochrome oxidase subunit 1 (COI) gene of members of the genus Cercamia (see Table 1) with Lachneratus phasmaticus as outgroup.Values on branches represent bootstrap proportions from 1000 replicates; scale bar shows average number of nucleotide substitutions. Sequence of holotype of Cercamia spio n. sp. in bold. Origin of sequences is as follows: (P) = present study; (I) = Isari et al. (2017); (B) = BOLD; (M) = Mabuchi et al. (2014); (TR) = Thacker & Roje (2009); (A) = Allen et al. (2015).

FIGURE 11. Cercamia laamu n. sp., WAM P34839.002, holotype, 30.5 mm SL, Olhuveli I., Laamu Atoll, Maldives. A: postmortem; B: preserved in 70% ethanol; C: Cercamia laamu n. sp., alive individual, not collected, outside Dhigura Lagoon, South Ari Atoll, Maldives. Photos by M.V. Erdmann (A), T. Fraser (B), A. Ryanskiy (C).

FIGURE 17. Collection and photographic sites for Cercamia spio n. sp. (white circles, star = holotype, Red Sea only), Cercamia mascarene n. sp. (yellow star = holotype), Cercamia laamu n. sp. (blue star = holotype & blue circles = paratypes), Cercamia eremia (red circles, star = holotype).