Manningis arabicum ( Jones and Clayton, 1983 )

Manningis arabicum ( Jones and Clayton, 1983) View in CoL

( Fig. 1 View Figure 1 )

Paracleistostoma arabicum Jones and Clayton, 1983: 190 View in CoL , fig. 4.

Paracleistostoma arabicum View in CoL — Jones, 1986: 158, pl 46; Manning, 1991: 299, 300; Apel, 1994: 42–45, figs. 1, 2; Apel, 1996: 42–45, figs. 1, 2.

Manningis arabicum View in CoL — Al-Khayat and Jones, 1996: 798, 809, fig. 7; Al-Khayat and Jones, 1999: 58, 61; Apel and Türkay, 1999: 135; Ng et al., 2008: 233 (in list); Ng et al., 2009: 10 View Cited Treatment , 11, figs. 1b, 4; Naderloo and Türkay, 2012: 49 View Cited Treatment ; Naderloo et al., 2013: 450, tab. 1, 456, tab. 2; Naderloo, 2017: 371, figs. 34.3, 34.4, 34.10b

Material examined. Ten females (CL: 2.77 mm – 4.43 mm, CW: 4.21 mm – 7.43 mm), LFSc. ZRC –156, Jakhau (23°13’58”N 68°36’42”E), Gujarat, India, mangrove muddy shore, coll. J. N. Trivedi, 7 July 2015 GoogleMaps .

Diagnosis (modified from Ng et al., 2009).Carapace ( Fig. 1a View Figure 1 ) smooth, much broader than long, glabrous, dorsal surface sloping downward from posterior to anterior portion; gastric region moderately convex; anterolateral margins acute, convex, produced into 2 lobes posterior to external orbital tooth;lateral margins with 2 feeble indentations and continuing posteriorly as granulate ridges over part of the branchial region; posterior carapace margin wide, thickened, straight; front ( Fig. 1a, c View Figure 1 ) almost as wide as orbital, deflexed downward, concave and weakly bilobed from dorsal view; frontomedial margin distinctly bilobed; lateral angle of front touching inner infraorbital angle, then closing orbit; ex-orbital angle pointed, directed outward. Posteromedian tooth of epistome broadly triangular, lateral margins concave; posterior margin on either side concave.Third maxilliped ( Fig.1f View Figure 1 ) inner margin thick; merus slightly shorter than ischium, outer distal angle slightly broad, rounded; ischium with inner distal angle slightly produced, oblique line of setae present; basal segment of palp not excavated to form spatulate structure. Chelipeds ( Fig. 1a, b View Figure 1 ) of female slender, setose, tips spatulate; fingers ( Fig. 1d View Figure 1 ) longer than palm; P3 longest, P5 shortest, meri of P3 with anterior, dorsal surface granular, never spinulate or serrate; thoracic ( Fig. 1b View Figure 1 ) sternum swollen. Pleon ( Fig. 1b, e View Figure 1 ) subcircular, wider than long, visible dorsally, sutures visible, all somites free, telson triangular. Gonopore large, with outer margin almost straight, operculum small, directed forwards.

Remarks. The specimens examined in the present study show close agreement with the original description given by Jones and Clayton (1983) and Ng et al. (2009). Manning (1991) while describing a new genus Nasima Manning, 1991 for Cleistostoma dotilliformis Alcock, 1900 commented that a new genus should be established for Paracleistostoma arabicum Jones and Clayton, 1983 . Later, Al-Khayat and Jones (1996) established a new genus, Manningis for P. arabicum . The male and female of M. arabicum look similar in their overall morphology but show sexual dimorphism in relative cheliped size where males bear well developed and robust chelipeds and females bear slender chelipeds with a spatulate tip.

Manningis View in CoL closely resembles Nasima View in CoL , but can be distinguished from the latter on the basis of the following characters: robust chelipeds in the male, having a quadrangular palm, while the female has a slender cheliped with the palm longer than broad(versus chelipeds similar in the male and female of Nasima, Al-Khayat and Jones, 1996 View in CoL ; Ng et al., 2009, fig. 5a–c), carapace average width to length ratio is 1.6–1.7 ( Fig. 1a View Figure 1 ) (versus carapace average width to length ratio is 1.4 in Nasima, Ng et al., 2009 View in CoL , fig. 6A), carapace transversely oval in outline ( Fig. 1a View Figure 1 ) (versus carapace subquadrate in outline in Nasima, Ng et al., 2009 View in CoL , fig. 6A), posterior carapace margin comparatively broad ( Fig. 1a View Figure 1 ) (versus posterior carapace margin narrow in Nasima, Ng et al., 2009 View in CoL , fig. 6A).

Manningis View in CoL also resembles Serenella Manning and Holthuis, 1981 View in CoL but differs from the latter in the following characters: carapace transversely oval in outline ( Fig. 1a View Figure 1 ) (versus carapace quadrangular in outline in Serenella, Manning and Holthuis, 1981 View in CoL , fig. 55a), the lateral angle of front touching infraorbital tooth, thus effectively closing the orbit in Manningis View in CoL ( Fig.1c View Figure 1 ) (versus the lateral angle of front not touching inner infraorbital angle in Serenella View in CoL ); the posteromedial tooth of the epistome is broadly triangular in Manningis View in CoL ( Fig.1c View Figure 1 )(versus posteromedial tooth is acutely triangular in Serenella View in CoL ).

Manningis View in CoL can also be differentiated from Baruna Stebbing, 1904 View in CoL on the basis of the following characters: carapace transversely oval in outline ( Fig. 1a View Figure 1 ) (versus carapace subquadrangular in outline in Baruna, Harminto and Ng, 1991 View in CoL , fig.3e), anterolateral margin granular with two weak lobes ( Fig.1a View Figure 1 ) (versus anterolateral margin divided into three lobes, nearest the orbit being the largest with 6 or 7 marginal granules in Baruna, Harminto and Ng, 1991 View in CoL , fig. 3e), third maxilliped merus slightly shorter than ischium ( Fig. 1f View Figure 1 ) (versus merus larger than ischium in Baruna, Harminto and Ng, 1991 View in CoL ).

Manningis View in CoL can be differentiated from Camptandrium Stimpson, 1858 View in CoL on the basis of the following characters: carapace average width to length ratio is 1.6–1.7 ( Fig.1a View Figure 1 ) (versus carapace average width to length ratio is 1.3 in Camptandrium, Tan and Ng, 1999 View in CoL , fig. 1A, E), carapace transversely oval in outline ( Fig. 1a View Figure 1 ) (versus carapace hexagonal in outline in Camptandrium, Tan and Ng, 1999 View in CoL , fig. 1A, E), anterolateral margin with two weak lobes ( Fig. 1a View Figure 1 ) (versus anterolateral margin with 2 to 3 teeth in Camptandrium, Tan and Ng, 1999 View in CoL , fig. 1A, E)

Manningis View in CoL can be differentiated from Opusia Ng, Rahayu and Naser, 2009 View in CoL on the basis of the following characters:front weakly bilobed from dorsal view ( Fig. 1a View Figure 1 ) (versus front entirely straight from dorsal view in Opusia, Ng et al., 2009 View in CoL , fig. 2A), frontomedial margin distinctly bilobed ( Fig. 1a View Figure 1 ) (versus frontomedial margin broadly triangular ending in truncate tip in Opusia, Ng et al., 2009 View in CoL , fig. 2A), eyestalks without setae ( Fig. 1a, c View Figure 1 ) (versus eyestalk with long, plumose setae in Opusia, Ng et al., 2009 View in CoL , fig. 2A, D), epistome with posteromedian tooth broadly triangular ( Fig. 1c View Figure 1 ) (versus epistome with posteromedian tooth large, long and moderately narrow in Opusia, Ng et al.,2009 View in CoL , fig.2D).

Manningis View in CoL can be differentiated from Leptochryseus Al-Khayat and Jones, 1996 View in CoL on the basis of the following characters: carapace average width to length ratio is 1.6–1.7 ( Fig. 1a View Figure 1 ) (versus carapace average width to length ratio is 1.3 in Leptochryseus, Ng et al., 2009 View in CoL , fig. 11G), carapace transversely oval in outline ( Fig. 1a View Figure 1 ) (versus carapace quadrangular in outline in Leptochryseus, Ng et al., 2009 View in CoL , fig. 11G), front weakly bilobed from dorsal view ( Fig. 1a View Figure 1 ) (versus front gently concave from dorsal view in Leptochryseus, Ng et al., 2009 View in CoL , fig. 11G).

Manningis arabicum View in CoL was originally described from specimens collected from Kuwait ( Jones and Clayton, 1983), and later it was recorded from the Persian Gulf – Iran ( Naderloo and Türkay, 2012; Naderloo et al., 2013), Iraq ( Ng et al., 2009), Saudi Arabia ( Apel, 1994), and Qatar ( Al-Khayat and Jones, 1996, 1999). Outside the Persian Gulf, it has been recorded from Pakistan ( Saher et al., 2017), and now it is also known from mangrove habitat of Jakhau port of Gujarat state, located on the northwestern coast of India. The species is found in the lower intertidal zone of mangrove habitat at Jakhau port where it shares habitat with Nasima dotilliformis (Alcock, 1900) View in CoL . Manningis arabicum View in CoL is a deposit feeder and is found in small burrows present along the bank of creeks passing through the mangroves.