Last update: 03 December 2016

Common names:

* proposed name

Synonyms:

Etymology:
'Periophthalmus' is a compound name from the Greek 'peri' (around), and 'ophthalmôn' (eye), which refers to the wide visual field of these species

'malaccensis' is an adjective from 'Malacca', which refers to the Straits of Malacca, where is the type locality (Singapore: Murdy, 1989)

Maximum recorded length:
100 mm SL (Eggert, 1935)

Live colouration (photos: pers. obs.: North Sulawesi):
background colour brownish, ventrally paler, but dark below head and on isthmus in several specimens; numerous tiny sky blue speckles on cheeks, opercula, and throat; sparse bluish iridescent speckles on flanks; irregular mottled pattern of dark brown blotches along flanks; 4-8 dorsal dark brown saddle-like diagonal bars often visible; D1 proximally brownish-red with numerous white spots in the middle and posterior portion (lacking or only present basally in some specimens), a dark brown inframarginal stripe sandwiched between a narrow and interrupted white stripe, and a transparent margin; spines with tips pigmented. D2 proximally dark brown with scattered and irregular white spots (or transparent with irregular brown blotches), a submarginal black stripe sandwiched between two white stripes (not evident in smaller specimens), and a reddish margin; pectoral fins dusky, with paler rays (with series of dark speckles in some specimens); caudal fin with series of large dark brown speckles on membrane and along rays; anal fin light to dark grey between rays. On the ventral side, pelvic fins proximally whitish, and distally dark grey with a narrow white margin; on the dorsal side, dark grey between rays

Colouration on preservation (Murdy, 1989; Eggert, 1935; pers. obs.: Philippines, North Sulawesi):
ground colour grey to dark brown on dorsum and flanks, ventrally paler; tiny pale speckles may be visible ventrally on head; the dorsal banded pattern may be preserved; D1 background light brown with numerous white spots and a broad dark brown inframarginal stripe sandwiched between a narrow trnasparent stripe and a pale to transparent margin; D2 background light brown with transparent spots proximally, a dark brown inframarginal stripe sandwiched between 2 transparent stripes, and a light brown margin; caudal fin with series of large dark speckles on membrane and along rays; pectoral fin dusky with paler rays; pigmentation of anal and pelvic fins is preserved

Diagnosis (Murdy, 1989; Eggert, 1935):
D1 IX-XI; total D2 elements 11-12; total anal fin elements 10-12; longitudinal scale count 47-61 (relatively large scales); predorsal scale count 31-32; TRDB 14-17; prominent transversal crease on snout; D1 with first spine elongated and with white spots proximally; pelvic fins partially united by a basal membrane, with a prominent frenum uniting the two spines; pelvic fins pigmented ventrally, and with a white margin; dorsal fins not connected by membrane; caudal fin with large speckles along rays, extending on membrane; minute sky blue speckles on head and iridescent bluish speckles on flanks.
The genus is yet undefined by synapomorphies

Diet:
no published study is available

Reproduction (pers. obs.: North Sulawesi):
no published study is available.
I observed a couple inside a burrow (Wawontulap, North Sulawesi, 2005). The two openings had turrets approx. 3-5 cm high

left: one of the specimens found inside the burrow, visible through one of the openings

Ecological notes (pers. obs.: North Sulawesi):
I found this species nearby the vegetated banks of the middle-upper tract of a tidal creek (approx. 1 km long), inside a mangrove forest, at a distance of approx. 2-10 m from the water edge during low tide

middle: mangrove forest along the banks of the "river" Talonka (photo: G. Polgar, Wawontulap, North Sulawesi, 2005)

Distribution (Murdy, 1989; Eggert, 1935; Polgar, 2016):
from Indonesia to the Philippines; type locality: Singapore

Remarks:
the type material was destroyed during World War II (Murdy, 1989). Murdy (1989) discriminated several specimens from Indonesia and the Philippines based on the original description by Eggert (1935).
Even if the type locality is Singapore, recent collections of mudskippers (e.g. Larson et al., 2008) were unable to find this species in this locality, where is now probably extinct

Photographs of Periophthalmus malaccensis:

A, B: specimen of P. malaccensis: notice the elongated D1 spine in A, visible also when he fin is appressed, and the dorsal banded pattern in B; C: a burrow with three openings; D: close-up of the specimen illustated in A, coming out of its burrow; E-G: details of anesthetised specimens (photos A-G: G. Polgar, Wawontulap, North Sulawesi, 2005); H: a dead specimen freshly fixed in formalin; I: a specimen in aquarium (photos H, I: Y. Ikebe, Haiphong, northern Viet Nam, 2000; Mudskipper World, 2008)* - * with permission

Drawings of Periophthalmus malaccensis:

left: cephalic sensory and nasal pores of Periophthalmus spp.: an= anterior nostril; pn= posterior nostril (modified from Murdy, 1989)*; right: drawings of the first dorsal fin (above) and of the pelvic fins (below: ventral view) of P. malaccensis (adapted from Eggert, 1935) - * with permission