White Lined Coralblenny

Description: Dorsal fin XII, 14, with deep notch between spinous and ray portions; anal fin II,15-17; pectoral rays 13; pelvic fin I, 3; caudal-fin segmented rays 13. Body depth 4.5-4.8 in SL at anal-fin origin. Vertebrae 10 + 22-23; incisors and anterior canine teeth look very similar, 44,46, and 47 in total; posterior canines 1 on each side, sometimes absent. Lateral line without pores, ends below dorsal spine 8-10. Anterior nostril with cirrus present only on posterior rim. Overall brown, anteriorly yellowish, dorsal side with two narrow pale stripes widely spaced. Eyes with narrow yellow ring around the pupil and yellow streaks on iris. Mid-postorbital margin with prominent dark spot. Pale stripe from eyes to posterior edge of operculum continuous with the ventral pale stripe on body. Dorsal-fin ray portion with suprabasal stripe, thin and dusky (Ref. 5296, 90102).

Oviparous, distinct pairing (Ref. 205).

Dorsal spines (total): 12; Dorsal soft rays (total): 14; Analspines: 2; Analsoft rays: 16; Vertebrae: 32 - 33

Adults occur solitary or in small groups on sponges and corals (Ref. 90102). Oviparous. Eggs are demersal and adhesive (Ref. 205), and are attached to the substrate via a filamentous, adhesive pad or pedestal (Ref. 94114). Larvae are planktonic, often found in shallow, coastal waters (Ref. 94114).

Ecsenius taeniatus

DESCRIPTION (three specimens known).—Dorsal fin XII, 14. Anal fin II,16. Pectoral fin 13. Segmented caudal-fin rays 13. Vertebrae 10 + 22 or 23. Dentary incisor teeth (includes anterior canine teeth, which differ little, if at all, in appearance from incisors) 44, 46, and 47; posterior dentary canines 1 on each side. Lateral line without pairs of pores, terminating posteriorly at point between verticals from dorsal-fin spines 8 and 10. Cirrus present on posterior rim of anterior nostril; none on anterior rim.

Preserved Color: Head darkly dusky above horizontal at ventral orbital margin, pale dusky below; dark spot just posterior to postorbital margin, fading posteriorly and continuing as diffuse stripe across head; ventral surface of head faintly dusky with single, slender, curved, pale area, or linear pair of pale spots, on each side. Body with slender, pale stripe originating in region dorsal to pectoral-fin axil and extending posteriorly along body midline almost to caudal-fin base; body darkly dusky above stripe, paler below; another slender, pale stripe originating at about vertical from dorsal-fin origin, extending posteriorly between lateral line and dorsal body contour, and ending at about vertical from midbase of segmented-ray portion of dorsal fin; ventral third of fleshy pectoral-fin base pale dusky, abruptly darker on upper two-thirds. Spinous-dorsal fin with scattered melanophores basally, giving rise to dusky extensions along spines; segmented-ray portion with suprabasal slender, diffusely dusky stripe of melanophores. Anal fin almost uniformly covered with fine melanophores. Caudal fin dusky basally with diffuse extensions of melanophores along central rays. Pectoral and pelvic fins scarcely marked.

COMPARISONS.—Ecsenius taeniatus appears to be most similar in color pattern (most closely related to?) E. prooculis, with which it is easily confused on superficial examination. Both species have two pale stripes alternating with two dark stripes on the side of the body, but the dorsal pale stripe in E. prooculis is ventral to the level of the lateral line, whereas in E. taeniatus it is just dorsal to the lateral line. The ventral pale stripe of E. prooculis is well ventral to the mid-line of the body, whereas in E. taeniatus it is on the mid-line. Additionally, the pale stripes of E. prooculis are about twice as deep as those of E. taeniatus. Ecsenius prooculis never has a conspicuous dark spot on the mid-postorbital margin, as is present in E. taeniatus, but often exhibits a slender, dark postorbital stripe, which is not present in E. taeniatus.

These two species are allopatric. If they form a monophyletic group, as I think they may, an explanation of their origins is possibly to be found in the tectonic events that separated the islands of the Bismarck and Solomon plates from the north coast of New Guinea. Kroenke (1984:35) has written,

…at 3.5 Ma…the New Britain Arc and Papua New Guinea mainland were separated by more than 300 km. Further back in time near the Mio-Pliocene boundary (5 Ma), the New Britain Arc and the Papua New Guinea mainland [now in contact] were separated by more than 500 km and exhibited no interdependence. Thus, as they were separate entities, the pre-Pliocene development of New Britain (as part of the Manus-New Ireland-Solomon Island Arc) and that of the New Guinea mainland can be viewed independently.

These circumstances would seem to indicate that a common ancestor of the putative prooculis-taeniatus clade would have had to exist prior to 5 m.y.a. and would have been broadly distributed over a rather extensive range that included a connection, such as stepping-stone islands, between New Guinea and the New Britain–Manus–New Ireland–Solomon Island Arc. Subsequent loss (possibly by submergence) of the connection would have isolated New Guinea and the Island Arc, thus also isolating populations in each area that subsequently diverged. There is, however, no evidence for the existence of the necessary connection. The issue becomes even more complicated when one realizes that four of the five species of the Prooculis Group exist allopatrically either on the New Guinea coast or on the islands adjacent to the coast (the hypothesized scenario could hold if any of the three other New Guinea species, or combinations of them, is the sister group of E. prooculis).

DISTRIBUTION.—Known only from Goodenough Island, D'Entrecasteaux Islands, and nearby Basilaki Island, Papua-New Guinea.

ETYMOLOGY.—The species name is from the Latin taenia, meaning stripe, and refers to the stripes on the body.

HOLOTYPE.—USNM 277494, female, 32 mm SL, Papua-New Guinea, Milne Bay District, Basilaki Island, coral reef, 0–20 ft [0–6 m], Tyson Roberts, 22–25 August 1975.

PARATYPES.—USNM 217566, male, 28 mm SL, collected with the holotype. WAM P24913, male, 32 mm SL, D'Entrecasteaux Islands, Goodenough Island, G.R. Allen, 28 May 1972.

PICTUS GROUP

This group comprises a single species, Ecsenius pictus. I am unable to hypothesize its sister group, which is probably among those species groups that, like E. pictus, are characterized by having a dark postorbital stripe and deeply incised dorsal fin: Lineatus, Mandibularis, Oculus, Opsifrontalis, Prooculis, Yaeyamaensis. The Pictus Group and all these groups, except the Lineatus Group, are also characterized by having relatively low fin-ray and caudal vertebral counts (all other species groups of Ecsenius have high counts). The color pattern of E. pictus is distinctive (see description below) and sets it apart from all other species of Ecsenius.

It is of interest, perhaps, that among the six groups listed above, E. pictus comes closest to being completely allopatric to the Lineatus Group, which is the only one of the six that is monotypic. I find no character that would indicate that E. pictus might be more closely related to E. lineatus than to another of the six species groups, unless the low meristics of E. pictus are specializations shared with one or more of the groups that also exhibit them.

Ecsenius pictus McKinney and Springer

Ecsenius pictus McKinney and Springer, 1976:19 [Great Banda Island, Molucca Islands, Indonesia; holotype, USNM 213853].

DESCRIPTION.—Dorsal fin XII, 13–15, deeply notched between spinous and segmented-ray portions. Anal fin II,15–17. Pectoral fin 13 (rarely 12 or 14 unilaterally). Segmented caudal-fin rays 13. Vertebrae 10 + 21–23 (rarely 23). Dentary incisor teeth 40–48 (includes anterior canine teeth, which differ little, if at all, in appearance from incisors); posterior dentary canines 1 on each side (rarely 2). Lateral line without vertical pairs of pores, terminating posteriorly at point between verticals from dorsal-fin spines 8 and 11. Cirrus present on posterior rim of anterior nostril; none on anterior rim.

Preserved Color: In preservative, body dark brown with up to 8 pale pinstripes; mid-lateral pale stripe often with series of pale enlargements (spots) along its length; irregular row of pale spots often present near dorsal body contour, spots ending well before caudal peduncle; caudal peduncle with irregular, broad, pale and dark markings, sometimes appearing as alternating pale and dark bands (up to 4 pale and 3 dark). Mid-lateral pale stripe on body and another above it extend anteriorly on head to posterior margin of orbit; dark postorbital stripe often inconspicuous (see life color below). Head and cheeks dorsally as dark as body or considerably paler; underside of head less dark than dorsal surface; lower lip darkly dusky anteriorly, followed posteriorly by narrow, immaculate, pale area, and diffuse darkly dusky area. Pectoral-fin base with prominent pale stripe; irregular pale markings often present dorsal to stripe. Pectoral and caudal fins with dusky pigment along rays. Anal fin dusky with indistinct pale basal stripe. Dorsal fin dusky at base and along proximal half of rays; diffuse pale stripe may interrupt dusky basal area. Pelvic fins unmarked or faintly dusky proximally.

Live Color (based on color photographs published by Debelius (1986:92) and taken in the wild at Kakabia Island, Indonesia; augmented by photographs of fresh specimens from the Molucca and Solomon islands): Head paler than body, brownish dorsally above mid-orbital level, paler pinkish brown below; iris of eye with almost complete bright-white ring around pupil (ring with gap ventrally); about 4 bright-yellow spokes radiating dorsally from ring; bright-yellow spots in dark part of iris between spokes; fine, bright-yellow spots in two lines across front of snout; fine, bright-white stripe dorsally on each side of interorbital area; bright-yellow spot on postorbital margin at 2 o’clock position, short, fine, bright-yellow stripe at 3 o’clock position, and bright-white stripe at 4 o’clock position extending posteriorly across head onto body (3 and 4 o’clock stripes border dark postorbital stripe); ground color of body dark purplish brown; spots and pinstripes on body brilliant white, pale bands on caudal peduncle pale yellow, of which anteriormost is saddle-like and, in living individuals, brightest; bands equally yellow in freshly collected specimens.

The photograph published in Debelius (1986), shows an individual that conforms with the above description, except that there is no white ring around the pupil; instead, two fine, bright stripes, more or less continuous with the 3 and 4 o’clock stripes (see above), pass dorsal and ventral to the pupil (ventral stripe interrupted by pupil); and 3 o’clock stripe extends across head to body. In photographs of fresh specimens from the Molucca and Solomon islands, the area around the mouth and underside of the head are yellow.

SEXUAL DIMORPHISM.—Female specimens from the Philippine Islands have significantly higher average numbers of dentary incisor teeth than do males (t = 3.03; p = < 0.01; df = 23; Table 29).

GEOGRAPHIC VARIATION.—Specimens from the Solomon Islands have more dentary incisor teeth and higher average meristics than specimens from the Philippine, Molucca, and Bone Rate islands (Table 29).

DISTRIBUTION.—Known only from the Philippines; Indonesia: Molucca (Great Banda, Saparua) and Bone Rate (Telerang, Kakabia) islands; and Solomon Islands: Malaita.

MATERIAL (* = new material).—Indonesia: Great Banda Island, USNM 213853 (holotype: 33 mm SL), 211895 (1 specimen: 31), CAS 34245 (1:23); Saparua, USNM 210056 (1:18); Moromaho Island, CAS 59539* (1:33); Bone Rate Group, Telerang, BPBM 31513* (3:21–34), Kakabia, BPBM 31497* (1:21). Solomon Islands: Alite Reef off Malaita, BPBM 15612 (1:35), 15624 (1:35), 15940 (1:37); Guadalcanal, BPBM 19016 (1:20). Philippine Islands: Siquijor Island, USNM 219316* (1:36), 219319* (1:40), 226995* (1:16), 227001* (4:14–38); Balicasag Island, USNM 226996* (5:14–41); Solino Island, Mindanao, USNM 226997* (1:50); Negros Island, USNM 219310* (2:38, 50), 219314* (2:35, 39); Pescador Island, Cebu, USNM 226994* (2:30, 37), 226998* (3:28–36); Mactan Island, Cebu, USNM 219318* (2:18, 31), 227000* (1:25); Cebu, USNM 226999* (6:28–37).

MANDIBULARIS GROUP

This group comprises four species: E. mandibularis, E. schroederi, E. aequalis, and E. kurti. The hypothesized synapomorphy that I believe indicates the monophyly of the group pertains to the number of posterior canine teeth: in specimens over 25 mm SL, there are 4–8 posterior canine teeth on at least one side (dentary bone) of the lower jaw (usually both dentaries have at least 4). All other species of Ecsenius normally have only 1 posterior canine tooth on each side, and never have more than 2. The posterior canines are arranged in a row perpendicular to the row of incisoriform teeth. The only other genus of Blenniidae that normally has more than one posterior canine tooth on each side is the monotypic salariinin genus Glyptoparus Smith. Glyptoparus exhibits no other specialization that might indicate it as the sister group of Ecsenius, and I believe that the presence of multiple posterior canines in the two genera is homoplasious.

The species of the Mandibularis Group are moderately small, attaining a maximum SL of about 33–51 mm, and have deeply-notched dorsal fins and similar meristics. They differ primarily in color pattern. The species are allopatric for the most part, but the Great Barrier Reef portion of the range of E. aequalis overlaps the northern portion of the range of E. mandibularis. There are considerable gaps between and/or within the ranges of the species; more so than one would expect if the gaps are not collecting artifacts. I am unable to hypothesize unequivocally the intragroup relationships.

Ecsenius taeniatus, the white-lined coralblenny, is a species of combtooth blenny in the genus Ecsenius. It is found in coral reefs in the western central Pacific ocean, around several islands in Papua New Guinea. It can reach a maximum length of 3.2 centimetres. Blennies in this species feed primarily off of plants, including benthic algae and weeds.