Common names:

* proposed name

Synonyms:

*In: Cuvier & Valenciennes, 1837

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

'novemradiatus' means 'with nine rays' in Latin, which refers to the number of spines in D1

Maximum recorded length:
64 mm SL (Murdy, 1989)

Live colouration (Murdy, 1989; pers. obs.: Peninsular Malaysia):
ground colour dorsally and laterally brown, ventrally whitish to grey; ventroposterior edge of the gill cover blackened; head and trunk with numerous dark brown blotches, larger on trunk; tiny iridiscent bluish speckles on cheecks and flanks; 5-8 diagonal, irregular saddle-like dark brown bars on dorsum; D1 with a transparent background and proximal red flecks between elements; a greyish inframarginal stripe, anteriorly darker; and a translucent margin; D2 with a series of brown to reddish spots proximally; a dark brown inframarginal stripe; and yellow margin; caudal fin membrane dusky, rays distally orange with series of brownish speckles; pectoral fins distally orange; anal fin yellowish; pelvic fins whitish to dusky

Colouration on preservation (Murdy, 1989; pers. obs.):
ground colour pale to dark brown dorsally and laterally, whitish to greyish ventrally; irregular saddle bars usually present; scattered darker blotches on head and trunk; ventral margin of gill cover usually blackened; D1 background transparent with a dark inframarginal stripe and dark to dusky proximal spots between elements; D2 background transparent with a dark inframarginal stripe, and dusky spots basally between elements; caudal fin rays dusky with darker speckles on rays; anal fin whitish to hyaline; pectoral fin dusky; pelvic fin whitish to dusky

Diagnosis (Murdy, 1989):
D1 IX-XI; total elements of D2 13-14; total elements of anal fin 12-14; longitudinal scale count 61-76; TRDB 15-21; head width 13.2-18.6%SL; pelvic fin length 11.3-13.3%SL; length of anal fin base 19.1-24.0%SL; length of D2 base 21.9-25.9%SL; D1 with no stripes, reddish orange spots in life, dark spots on preservation, first spine moderately elongated in larger specimens; pelvic fins with prominent frenum and inner rays united for one quarter or less of their length.
The genus is yet undefined by synapomorphies

Diet:
carnivorous, opportunistic (crustaceans, insects, etc.: Swennen et al., 1995; pers. obs.)

Reproduction:
it digs turreted burrows in the high mangrove forest (pers. obs.); the details of its reproductive cycle have not been described in literature: it probably follows the general model proposed for all the congeneric species (see also Reproductive behaviour); no published study is available

Ecological notes (pers. obs.: Peninsular Malaysia):
locally abundant in mangrove ecosystems from the low forest to the high forest zone; larger individuals are capable to live in the high supratidal zone; its disruptive colouration allows for efficient camouflage on the forest floor

middle: Carey Island, Malaysia: high mangrove forest; the typical habitat of P. novemradiatus (photo: G. Polgar, 2006)

Distribution:
Indo-Pacific region, from the East coast of India to the Philippines; type locality: vicinity of Calcutta (Murdy, 1989)

Photographs of Periophthalmus novemradiatus:

A: P. novemradiatus, high forest (photo: G. Polgar; Sementa, Peninsular Malaysia, 2006); B: a specimen captured by hand net (photo: G. Polgar; Sementa, Peninsular Malaysia, 2006); C: a turreted burrow of P. novemradiatus (photo: G. Polgar; Sementa, Peninsular Malaysia, 2006); D: P. novemradiatus taking shelter from water on the prop roots of Rhizophora sp. at high tide (photo: G. Polgar; Kukup Is., Peninsular Malaysia, 2006); E: P. novemradiatus coming out of its burrow (photo: M.Z. Khaironizam; Kuala Selangor, Peninsular Malaysia, 2001)*; F: close-up (photo: Y. Ikebe, Southern Thailand: Ranong; mudskipperworld)*; G: P. novemradiatus perching on a root at high tide (photo: G. Polgar; Kukup Is., Peninsular Malaysia, 2007)*; H: the efficacy of the cryptic colouration on the forest floor (photo: G. Polgar; Kuala Selangor, Peninsular Malaysia, 1996); I: another close-up at low tide (photo: G. Polgar; Kuala Selangor, Peninsular Malaysia, 1996); J: P. novemradiatus in aquarium (photo: G. Polgar; Kukup Is., Peninsular Malaysia, 2007); K: an individual resting on a log at high tide (photo: G. Polgar; Kukup Is., Peninsular Malaysia, 2007)* with permission

Drawings of Periophthalmus novemradiatus:

cephalic sensory and nasal pores of Periophthalmus spp.: an= anterior nostril; pn= posterior nostril (modified from Murdy, 1989)* - * with permission