Paromolopsis boasi Wood-Mason

Muñoz, Isabel, García-Isarch, Eva & Cuesta, Jose A., 2021, Annotated and updated checklist of marine crabs (Decapoda: Brachyura) of Mozambique supported by morphological and molecular data from shelf and slope species of the “ MOZAMBIQUE ” surveys, Zootaxa 5056 (1), pp. 1-67 : 14-15

Paromolopsis boasi Wood-Mason in Wood-Mason & Alcock, 1891

( Figures 2E , 3 )

Material examined. M08, Stn. 39, 631m, ♀ ov 39× 43.6mm (IEO-CD-MZ08/1827), 16S ( MZ 424914 ) , COI ( MZ 434762 ) ; M09, Stn. 65, 578m, ♂ 34× 38.9mm (IEO-CD-MZ09/1762), 16S ( MZ 424915 ) , COI ( MZ 434763 ) .

Habitat and distribution. Paromolopsis boasi was the only species of the genus worldwide, until Paromolopsis piersoni (Schweitzer et al. 2004) was described from fossil records in Oregon (Pacific Northwest of North America). This species presents an IP distribution: Madagascar, Channel of Mozambique, Mayotte Island, La Reunion, Sri Lanka, Andaman Island, Laquedives Island, Indo-Malaysian Archipelago, New Caledonia, Queensland and Japan. It inhabits mud bottoms, from 284 to 1124m (most common between 400 and 700m) ( Guinot & Richer de Forges 1995; Poupin 2010, 2018).

Results and remarks. This work provides the first record of P. boasi from Mozambique waters. Only two specimens of P. boasi were collected in M08 and M09, between 578–631m depth. Our specimens were identified using the descriptions given by Guinot & Richer de Forges (1995) and Schweitzer et al. (2004).

Guinot and Richer de Forges (1995) had already doubted about the validity of a single species from all the known localities of P. boasi , pointing out differences in the dorsal carapace ornamentation, variation in body tomentum and carapace proportions and different sizes of frontal spines. This fact was also raised by Padate et al. (2020), who found differences between Indian and Pacific specimens. Guinot and Richer de Forges (1995) already suggested the potential separation of P. boasi into at least two species. A review of this genus, including genetic analysis of P. boasi specimens from different areas is recommended to clarify this issue.

The most remarkable characteristics of these two specimens (see Figure 3 ) are: anterolateral spines acute but not sharpening towards the end; dorsal face of the carapace quite rough and grainy; merus length of P5 does not exceed the anterolateral spine; long setae on the edges of the carapace, as well as on the edges of the ambulatory legs; the top edge of P2-P4 merus armed with separated spines of different size, not uniform in number neither between different pereiopods nor between specimens. The biggest specimen (IEO-CD-MZ08/1827) is an ovigerous female that responds to the next pattern from the outside inward (see Figure 3B ): right side, P2, two sharp, curved and well separated medium-size spines + two small blunt and less separated spines or tubercles, not clearly visible; P3, four well visible spines on merus, that decrease dorsally in size and space between them; P4, three well visible, pointed and curved spines, diminishing in size dorsally; left side, P2, small tubercles in the most proximal area; P3, three well visible and curved spines (two last broken); P4, two well visible and curved size-decreasing spines. The male (IEO-CD-MZ09/1762), responds to (see Figure 3C ): right side, P2, two big, pointed and curved spines + four smaller spines, neither pointed nor curved, which decrease in size dorsally until being almost inconspicuous and adjacent; P3, four pointed and curved and dorsally size-diminishing; P4, four pointed and curved spines becoming much smaller towards the dorsal zone; left side, P2, three big, pointed and curved spines, being the two first specially big + two neither pointed nor curved small spines, almost inconspicuous; P3, five spines that decrease in size and space between them, the last neither pointed nor curved, P4, four pointed and curved spines, with dorsally diminishing size. All these characters are in line with the characteristics of the specimens cited in waters of the Indian Ocean (Guinto & Richer de Forges, 1995).

Colouration observed. Carapace was bright orange, with the most depressed areas of the gastric zones white. Meri of the ambulatory legs were also orange, slightly pinker in their proximal area; carpi are orange-pink; propodi are whitish with pink tones and the dactyli almost white.

DNA barcodes. 16S and COI sequences obtained for the two specimens are equal in 500 and 639 bp, respectively. The 16S sequence fits 100% with an incomplete sequence of P. boasi of 406 bp (hypervariable parts deleted) from Taiwan (?) ( NTOU B00091, Genbank code KJ132606 ) included in the study by Tsang et al. (2014). The COI sequence is the first one available for this species.

Family LATREILLIIDAE Stimpson, 1858

According to Davie et al. (2015a), Latreillidae includes two genera, Latreillia P. Roux and Eplumula Williams , and seven species, three of them cited in Mozambican waters ( Latreillia metanesa Williams , Latreillia pennifera Alcock and Latreillia valida De Haan ) ( Kensley 1981; Poupin 2010, 2018, Emmerson 2016b,c). Free living and mostly deep water species, individuals typically carry seaweeds, hydroids, gorgonians and/or corals on them ( Davie et al. 2015b).

Figures

FIGURE 3. A, Paromolopsis boasi IEO-CD-MZ09/1762 ♂, dorsal view; B, P. boasi ♀ov IEO-CD-MZ08/1827 P2-P3-P4 left and right; C, P. boasi IEO-CD-MZ09/1762 ♂ P2-P3-P4 left and right. Scale bars: 1cm.

FIGURE2.A,Homolodromiabouvieri,♀ IEO-CD-MZ08/1801;B,Homola orientalis,♂IEO-CD-MZ09/1806;C,Homolochunia valdiviae, ♀ IEO-CD-MZ09/1805; D, Moloha alcocki, ♀ IEO-CD-MZ09/1793;E, Paromolopsis boasi, ♀ IEO-CD-MOZ08/1827; F, Latreilla metanessa, ♀ IEO-CD-MZ09/1810; G, Latreilla valida, ♀ IEO-CD-MZ09/1779. Scale bars: 1cm.