Cercamia mascarene, 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 : 380-383

Cercamia mascarene new species

( Figures 10B & C , 12 , 13 & 17 , Tables 2 & 3)

Mascarene Cardinalfish

Cercamia eremia (non Allen)— Heemstra et al. 2004: 3320 (Rodrigues Island).

Holotype: SAIAB 70012 , 33.5 mm SL, Mauritius, Rodrigues Island, Off Riviere Banane , 19°40’05’’S, 63°28’22’’E, ROD-35, 21– 22 m, 16 Oct 2001.

Paratypes: Mauritius, Rodrigues Island. ROM 74067, 3 , 33.1–33.9mm SL, off Riviere Banane , 19º40’05.7760”S, 63º28’13.1286”E, 16 Oct 2001 , ROD-35, 22 m; SAIAB 68959 , 3 , 24–40 mm SL, Grand Baie , 19°39’47’’S, 63°26’23’’E, ROD-15, 18 m, 24 Sep 2001 ; SAIAB 69006 , 7 , 22.4–40 mm SL, Grand Baie , 19°39’36’’S, 63°27’03’’E, ROD-16, 18– 21 m, 25 Sep 2001 ; SAIAB 69075 , 22 , 23.8–40.2 mm SL, Grand Pate , 19°39’18’’S, 63°24’57’’E, ROD-19, 15– 19 m, 29 Sep 2001 ; SAIAB 69829 , 3 , 25.9 –32.0 mm SL, Grand Baie , 19°39’01’’S, 63°26’25’’E, ROD-31, 20 m, 13 Oct 2001 , color photograph; SAIAB 207277 out of 70012, 2, 31.1–33.4 mm SL, Off Riviere Banane , 19°40’05’’S, 63°28’22’’E, ROD-35, 21– 22 m, 16 Oct 2001 .

Non-type material: SAIAB 69530 , 1 , 30.2 mm SL, Chaland , 19°40’04’’S, 63°24’43’’E, ROD-25, 20– 25 m, 9 Oct 2001 ; SAIAB 69841 , 2 , 29.0– 33.3 mm SL, Grand Pate , 19°39’01’’S, 63°24’50’’E, ROD-32, 27– 28 m, 14 Oct 2001 ; SAIAB 69871 , 7 , 21.5–32.9 mm SL, Baladirou , 19°39’43’’S, 63°27 27’’E, ROD-34, 18 m, 16 Oct 2001 ; SAIAB 70060 , 4 , 33–35.3 mm SL, Passe Grenade, 19°40’27’’S, 63°29’18’’E, ROD-37, 18 m, 17 Oct 2001 ; SAIAB 70258 , 3 , 16.4–31.7 mm SL, Passe Grenade, 19°39’11’’S, 63°25’42’’E, ROD-38, 18 Oct 2001 ; SAIAB 70294 , 5 , 16.0– 33.3 mm SL, Eric’s Pate , 19°39’ 5’’S, 63°25’46’’E, ROD-40, 18 m, 20 Oct 2001 ; SAIAB 70334 , 1 , 32.3 mm SL, Yacht Casse , 19°40’01’’S, 63°24’53’’E, ROD-41, 17– 20 m, 21 Oct 2001 ; SAIAB 70418 , 3 , 22.8–33.4 mm SL ,

Grande Bassin, 19 38’50’’S, 63°20’57’’E, ROD-42, 19– 20 m, 22 Oct 2001; SAIAB 70432 , 4 , 23–33.9 mm SL, Eric’s Pate, 19°39’12’’S, 63°20’57’’ E, ROD-43, 17 m, 22 Oct 2001; SAIAB 70500 , 2 , 20.7–36.5 mm SL, off Ile aux Sables, 19°41’38’’S, 63°17’36’’E, ROD-44, 18– 21 m, 23 Oct 2001.

Diagnosis. A species of Cercamia with anal-fin spines and rays usually II,12–13 (rarely 11 or 14); second dorsal-fin spine and rays I,9; developed gill rakers on upper limb 1, developed gill rakers on lower limb 11–14 (usually 13); translucent, body with reddish dots and crosshatching; cheek usually with stellate melanophores ( Fig. 12B ).

Description. Holotype ( Fig. 12A ), proportions (as percentages of standard length), paratypes in parenthesis: greatest body depth 30.4 (23.3–30.4); head length 35.4 (32.2–35.4); eye diameter 10.8 (10.8); snout length 9.5 (6.3–9.5); bony interorbital width 6.3 (5.1–6.3); upper-jaw length 16.8 (16.8–17.0); caudal-peduncle depth 8.9 (8.9–11.3); caudal-peduncle length 26.2 (26.2); first dorsal-fin spine length 10.8 (9.8–10.8); second dorsal-fin spine length 13.2 (12.7–13.2); third dorsal-fin spine length 12.7 (10.8–12.7); fourth dorsal-fin spine length 10.4 (10.4); spine in second dorsal fin 6.3 (6.3–8.5); first anal-fin spine length 3.8 (3.3–3.8); second anal-fin spine length 11.3 (8.9–11.3); pectoral-fin length 19.3 (15.5–19.3); pelvic-fin length 15.5 (14.1–15.5).

Dorsal fin VI–I,9, all segmented rays branched; anal fin II,12, 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 9 above, 9 below; caudal fin forked.

The preopercle with two tiny spines on edge near angle, tiny spine at angle of ridge. Posttemporal with a small spine. Infraorbitals smooth

Scales cycloid ( Fig. 10 B & C ), variably missing on nape, body and caudal peduncle; 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 rudiments and 1 developed gill raker on upper limb, lower limb with no rudiment and 12 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, ectopterygoid, endopteygoid and basihyal.

Paratypes ( Fig. 12B ): Dorsal fin VI–I,9, all segmented rays branched; anal fin II,11–14 (rarely 11 or 14), all segmented rays branched, last anal-fin ray split to base; left pectoral fin with 10 rays, right 10; pelvic fin I,5; principal caudal-fin rays 9+8, upper and lower principal caudal-fin rays unbranched; procurrent rays 9 above, 9 below; caudal fin forked.

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

Scales when present, cycloid, variably missing on nape, body and caudal peduncle; 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 1–2 rudiments and 1 developed gill raker on upper limb, lower limb with 0–1 rudiment and 12–14 (usually 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, ectopterygoid, endopteygoid and basihyal.

Postmortem color. Paratype ( Fig. 12B ): translucent pinkish, body with patterned cross-hatched reddish outline of scales, 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 onto caudal peduncle, and a series of tiny dark reddish spots slightly above the anal-fin base; abdominal region black with melanophores on peritoneum, narrow whitish band from near anterior vertebrae downward to just anterior to anal-fin origin, and blackish area above along vertebrae; snout, jaws and gular regions reddish, about 8 stellate melanophores on preopercle and cheek behind orbit, iris golden; all fins translucent, caudal fin with vertical line of reddish dots.

Color in alcohol. Holotype in 70% ethanol ( Fig. 12A ): body a uniform light tan, fins without color patterns, scattered melanophores on posterior interorbit an over part of neurocranium, two (left) and four (right) small stellate melanophores on upper cheek, abdomen darkish from small melanophores associated with the peritoneum, whitish tissue surrounds the anal opening, no melanophores on gular region of lower jaw. Coloration of paratypes is similar to the holotype, with variable numbers of faint stellate melanophores.

Etymology. Mascarene, the geographic area in the southwestern Indian Ocean inclusive of Rodrigues Island where all known specimens were collected. A noun in apposition.

Distribution and Habitats. At present, appears as an endemic species to Rodrigues Island. Specimens were collected from caves in face of reef at openings, rubble at base, surge channels and coral reef with sand at base at depths of 15– 30 m.

Remarks. The body scales of this species are cycloid ( Fig. 10B & C ) including on the nape and caudal peduncle. Scales similar to Figure 16 fit Gon’s (2016) discussion of the early ontogeny formation in the Apogonidae : a central focus with 14 complete circuli (ridges, rings) suggests even scale growth. The existing scales barely overlap or have the rostral portion of the scale barely covered by skin. The dorsal head canal pattern ( Fig. 13 ) appears similar to those reported by Sato et al. (2019 fig. 3) for Cercamia eremia but with fewer pores.

Heemstra et al. (2004) did not identify any cardinalfish as endemic to Rodrigues Island. They reported fourteen new records in addition to the six species previously known. Two species were identified to genus only, Pseudamiops and Siphamia (as mossambica by Gon & Allen 2012). The species of Cercamia , here treated as an endemic (15 of 28 reef related stations), was initially reported as C. eremia by Heemstra et al. (2004). Thébaud et al. (2009) state that the oldest dated lava on Rodrigues is 1.5 million years ago but also state that the island could have been available for colonization for 8–15 million years ago. Cercamia has not been reported from Mauritius, Reunion or Saint Brandon (Cargados Carajos) Shoals, but should be expected from the first two volcanic islands. The postmortem color pattern is very similar to C. eremia , C. spio , and C. cladara suggesting that gill raker and anal fin-ray counts along with COI sequences may be changing faster than color patterns. Dorsal view of the major pores associated with the cephalic lateralis canals is shown in Figure 13 .

Cercamia mascarene differs from C. eremia and C. spio in number of developed gill rakers on lower limb (usually 13 versus usually 11 or 12) and number of anal-fin rays (usually 13 versus usually 11 or 12), and differs from C. laamu in fewer rays in second dorsal fin (9 versus 10) and presence of red spots on body and stellate melanophores on cheek.

Unfortunately, no tissue sample of a specimen of C. mascarene was available for phylogenetic analyses of the COI barcoding region. Considering the relative widespread distribution of other members of the genus such as C. eremia (see above), the species might also be much more widespread in distribution than currently acknowledged. Hence, one of the four unidentified clades in the COI gene tree that could not be identified as one of the described species (i.e., Cercamia sp. 1 to sp. 4) could possibly represent this species. However, considering the very distant collection localities (Ryukyu Islands, Saipan and Fiji) of these species from the Mascarenes and the relatively confined distribution ranges of most species of the genus, this seems unlikely.

Figures

FIGURE 10. A: Cercamia cf. eremia, USNM 352627, 26.3 mm SL, Ishigaki-Shima, Japan, high on body near position if a lateral line scale were present, drawn attached, right side of body, shaded area is epidermis, inner circulus? Shown. Cercamia mascarene n. sp. (B & C), B: SAIAB 207277, 33.4 mm SL, paratype, Rodrigues Island, Mauritius, left side cycloid body scales removed and stained with alizarin. near midline of body with 9 partial circuli; C: high on body near position if a lateral line scale were present, a nearly circular scale with 14 complete circuli (inner circulus? only shown).

FIGURE 12. Cercamia mascarene n. sp. A: SAIAB 70012, preserved holotype, 33.0 mm SL, Off Riviere Banane, Rodrigues Island, Mauritius; B: SAIAB 68959, paratype, postmortem, Grand Baie, Rodrigues Island, Mauritius. Photos by T. Fraser (A), by P. Heemstra edited by T. Fraser (B).

FIGURE 13. Cercamia mascarene n. sp., SAIAB 207277, 33.4 mm SL, Rodrigues Island, Mauritius, dorsal view of the major pores associated with the cephalic lateralis canals. Not shown are the connections with the infraorbital (IO) and preoperculomandibular (PM) canals. COR = coronal commissure, SO = supraorbital canal, STC = supratemporal canal and pore (STP) and T = temporal canal. Small dots represent a partial complement of free neuromasts.

FIGURE 16. Cercamia spio n. sp., SMF 35891 [KAU13-451], holotype, Al Wajh, Saudi Arabia, Red Sea, 33.2 mm SL. Positive from radiograph by S. Raredon. E=epural, H1 to 5=hypurals, HS= haemal spine, NC=neural crest, NF=neural foramina, NS=neural spine P=parhypural, PR=procurrent ray, TC=terminal centrum, UR=unbranched caudal ray.

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).