Gazia gazi Lowry & Springthorpe, 2019

Bichang’A, Joshua Sese, Kioko, Esther N., Liu, Hongguang, Li, Shuqiang & Hou, Zhonge, 2021, Two species of Talitridae (Crustacea, Amphipoda) from Kenya, Zootaxa 4927 (3), pp. 331-358 : 350-356

publication ID	https://doi.org/ 10.11646/zootaxa.4927.3.2
publication LSID	lsid:zoobank.org:pub:D3F302C7-DE38-4226-8BCD-06A82675105B
DOI	https://doi.org/10.5281/zenodo.4555606
persistent identifier	https://treatment.plazi.org/id/038BC150-3704-8A59-FF10-FDA1AC204104
treatment provided by	Plazi
scientific name	Gazia gazi Lowry & Springthorpe, 2019
status

Treatment

Gazia gazi Lowry & Springthorpe, 2019 View in CoL

( Figs 3 View FIGURE 3 , 16–19 View FIGURE 16 View FIGURE 17 View FIGURE 18 View FIGURE 19 )

Material examined. Male 7.5 mm ( NMK /INV/ AMP/0004 View Materials ) and female 8.5 mm ( NMK /INV/ AMP/0005 View Materials ), English Point Beach, Mkomani, Mombasa County, Kenya, S 04.05763 °, E 039.68376 °, 4 m a. s. l., 29 th July 2018, J. Sese and G. Kioko; one male and three females ( NMK /INV/ AMP/0006 View Materials ) same data as male 7.5 mm ( NMK /INV/ AMP/0004 View Materials ). One male specimen was used for molecular analysis and the sequence was submitted to GenBank ( MW 363128 View Materials ) GoogleMaps .

Ecological type. Beach hoppers supralittoral type, often burrowing in sand and leaf litter on the beach during low tide when temperatures are high. No Mangroves or other significant coastal vegetation was recorded at the collection site.

Diagnosis. Gazia gazi female can easily be identified by short antenna I reaching the base of article V of antenna II; antenna II shorter than half the body length; left mandible with five dentate incisor and four dentate lacinia mobilis; maxilliped palp article IV masked by palp article III; posterior margins of merus, carpus, and propodus of gnathopod II with tumescent hump; gnathopod II to pereopod V with oostegites, longer than wide, and with 6–11 fine smooth tipped setules; epimera II–III with vertical slits just above the ventral margin, 40 and 44 respectively; uropod I outer ramus without marginal spines; telson with seven robust spines per lobe.

Description based on female (NMK/INV/AMP/0005), 8.5 mm ( Fig. 3 View FIGURE 3 ). Antenna I ( Fig. 16A View FIGURE 16 ), short, reaching the base of peduncular article V of antenna II; peduncle with five articles; flagellum with three articles. Antenna II ( Fig. 16B View FIGURE 16 ), 0.2 times as long as body length; peduncular article III wider and shorter than articles IV and V; article V longest, 1.5 times as long as article IV; peduncular and flagella articles with many small, robust setae; flagellum with 19 articles and 2.2 times as long as peduncular article V, last article ( Fig. 16C View FIGURE 16 ) cone-shaped and bare.

Upper lip ( Fig. 16D View FIGURE 16 ), ventral margin of the apex rounded and setulose; mandibular processes present and well developed. Lower lip ( Fig. 16E View FIGURE 16 ), bilobed, apical and inner margins of the outer plate and central trough lined with fine setules. Left mandible ( Fig. 16F View FIGURE 16 ), incisor five-dentate, lacinia mobilis four-dentate, with pappose setae; molar well developed, with an accessory pappose seta. Maxilla I ( Fig. 16G View FIGURE 16 ), inner plate slender with two apical robust pappose setae; outer plate distal margin with nine robust setae of dentition formulae 5̅4̅5̅4̅2̅4̅3̅2̅3; one small articulate palp present. Maxilla II ( Fig. 16H View FIGURE 16 ), inner plate distal margin with more than 11 smooth-edged blunt setae, four rugged edged setae on the ventral side, and one large subapical pappose seta; outer plate with more than 15 smooth-edged short setae and at least four rugged edged setae. Maxilliped ( Fig. 16I View FIGURE 16 ), inner plate well developed, distal margin with three unequal sized stout teeth and pappose setae; outer plate exceeding palp article I, apical margin with robust setae; palp article II about 1.9 times as wide as long, with a well-developed distomedial lobe; palp article III longer than wide, with robust distal setae in two rows; article IV masked by palp article III distal setae.

Gnathopod I ( Fig. 17 View FIGURE 17 A–B), sexually dimorphic; coxa smaller than that of gnathopod II, ventral margin with seven small sharp spines; basis slightly enlarged towards the posterodistal end, anterior margin somewhat straight with seven setae, posterior margin slightly curved with one seta and two setae towards the base of the ischium; ischium posterior margin with six robust setae; posterior margins of the carpus, merus, and propodus without tumescent hump-like in their males instead, the margins well developed consisting of not less than seven bifid setae on the three articles; carpus about 1.7 times as long as propodus and with six robust bifid setae on the anterior margin; propodus reduced posterodistally, palm reduced, dactlylus cuspidactylate and attenuated distally. Gnathopod II ( Fig. 17 View FIGURE 17 C–D), sexually dimorphic; coxa ventral margin with 12 small sharp spines; basis proximally reduced and slightly expanded, anterior margin with 15 short sharp setae, posterior somewhat straight and bare; ischium longer than short with three robust setae on the posteroventral end; merus, carpus, and propodus posterior margins with well-modified tumescent humps; merus posterior margin with 11 robust bifid setae from the mid of the posterior margin to the base of the tumescent hump; carpus about 1.6 times as long as merus, anterior margin with three robust setae, posterior margin with one robust seta at the base of the tumescent hump; propodus longer than wide, with 15 robust bifid setae at the base of the tumescent hump, palm reduced, with a smooth anterior margin, anteroventral end (at the base of dactylus) with at least six robust setae, posterior margin with a bundle of three robust setae, dactylus subequal in length to palm.

Pereopods III̅VII ( Fig. 18 View FIGURE 18 A–E), cuspidactylate and similar in appearance to the male. Pereopod III ( Fig. 18A View FIGURE 18 ), considerably longer than pereopod IV; coxa wider than deep, with ten short, stout spines on the ventral margin; basis with five and six robust setae on the anterior and posterior margins respectively, slightly enlarged distally; ischium, 2.7, 1.5, and 1.1 times as long as merus, carpus, and propodus respectively; anterior margins of merus, carpus, and propodus, lined with stout bifid setae. Pereopod IV ( Fig. 18B View FIGURE 18 ), similar to pereopod III, dactylus shorter but wider anteriorly than that of pereopod III. Pereopod V ( Fig. 18C View FIGURE 18 ), coxa bilobed, with five short spines on the ventral margin of the smaller lobe; basis, ovoid with small sharp setae distinct on dorsal and ventral margins, posterodistal lobe present, merus enlarged distally; propodus slender and long, 1.3 times as long as carpus and merus; dactylus slender and attenuated distally. Pereopod VI ( Fig. 18D View FIGURE 18 ), coxa bilobed, posterior lobe posteroventral corner rounded, with seven short spines; basis ovoid, about 1.4 times longer than wide; merus, carpus, and propodus lengths in the ratio 4: 5: 7; dactylus nearly 1.2 times as long as that of pereopod V. Pereopod VII ( Fig. 18E View FIGURE 18 ), 1.6 times as long as pereopod III; coxa ovoid, ventral margin with four short setae; basis subcircular, posterior margin distinctly serrated, anterior margin with short spines, posterodistal lobe deep; merus, carpus, and propodus lengths in the ratio 5: 6: 7; dactylus ( Fig. 18J View FIGURE 18 ), slender and longest of all pereopods.

Oostegites, present on gnathopod II to pereopod V, longer than wide, and with 6–11 fine smooth-edged setules only from the midpoint to the distal end; shortest but widest in pereopod V. Coxal gills present on gnathopod II and pereopods III–VII, longest in pereopod VI.

Pleopods I–III ( Fig. 19 View FIGURE 19 A–C), all well developed, biramous, subequal in length, and rami with numerous plumose setae; coupling hooks present at the distal end of the peduncle. Pleopod I ( Fig. 19A View FIGURE 19 ), peduncle with one robust marginal seta; inner ramus with eight articles; outer ramus with nine articles. Pleopod II ( Fig. 19B View FIGURE 19 ), peduncle with four robust marginal setae; both rami with eight articles. Pleopod III ( Fig. 19C View FIGURE 19 ), peduncle with three robust marginal setae; inner and outer rami with eight and nine articles respectively.

Uropods I–II ( Fig. 19 View FIGURE 19 D–E), biramous; peduncles, about 1.3 times as long as both rami, with 13 and 12 robust marginal spines. Uropod I, inner ramus with five robust marginal spines and three apical spines; outer ramus without marginal spines but three robust apical spines. Uropod II inner ramus with two marginal spines and four apical spines; outer ramus with one marginal and four apical spines. Uropod III, ( Fig. 19F View FIGURE 19 ) uniramous and the smallest of the three; peduncle with three robust marginal spines; ramus with two marginal spines and three-terminal spines.

Epimera II–III ( Fig. 19 View FIGURE 19 H–I), with 41 and 44 vertical slits just above the ventral margin, respectively. Telson ( Fig. 19J View FIGURE 19 ), apically incised, bilobed, dorsal midline entire, with five bifid stout marginal setae and two stout bifid terminal setae per lobe.

Distribution. Kenyan coast, Gazi Beach (type locality) and English Point Beach, Mkomani (current study).

Remarks. A close comparison with Gazia gazi Lowry & Springthorpe, 2019 recorded from Gazi Beach, Kenya, revealed that the specimens from Mkomani, Kenya, belonged to Gazia by having: similar ecological type (beachhoppers); antenna I shorter than antenna II; four cuspidate left mandible lacinia mobilis; subchelate gnathopod I, with a well-developed tumescent hump only on the carpus and propodus posterior margins; bi-cuspidate pereopods III–VII; epimera II–III with slits just above the ventral margin; telson with spines in the range three to nine spines per lobe. The specimens resemble Gazia gazi Lowry & Springthorpe, 2019 in the male gnathopod II palm reaching 55% of the length of the propodus; four dentate lacinia mobilis on the left mandible ( Fig. 12J View FIGURE 12 ); maxilliped palp article IV being veiled by palp article III distal setae ( Fig. 12I View FIGURE 12 ); and similarity with pereopods III–VII ( Fig. 14 View FIGURE 14 ). Due to these resemblances, the specimens are presented as Gazia gazi ( Figs 3 View FIGURE 3 and 12–19 View FIGURE 12 View FIGURE 13 View FIGURE 14 View FIGURE 15 View FIGURE 16 View FIGURE 17 View FIGURE 18 View FIGURE 19 ). Gazia gazi is distinguishable from the South African G. ancheidos (Barnard, 1916) , G. samroiyodensis (Azman, Wongkamhaeng & Dumrongro- jwattana, 2014) from Thailand, G. guadalupensis ( Ciavatti, 1989) from the Caribbean Sea, and Madagascan G. itampolo ( Lowry & Springthorpe, 2015) by having a distinctively ridged palm posterior margin in male gnathopod II ( Fig. 13D View FIGURE 13 ).

Here we provide its female description, whose information was unknown from the original description ( Lowry & Springthorpe 2019). On the same note, a link to the molecular sequences used in the study is provided ( Table 1 View TABLE 1 ) and can be useful in other molecular studies.

Just as highlighted broadly, the incorporation of morphological and molecular data in species delimitation allows a high level of confidence, crucial for both biodiversity and ecological research ( Beermann et al. 2018; Dayrat 2005; Orr et al. 2020; Padial et al. 2010). Therefore, to ensure an improved species discovery and description, taxonomy needs to be consolidative to keep up with the constantly rising demand for accurate biodiversity data.

Besides the Talitridae family, four more families have been registered from Kenya. They include Amphilochidae , with one species, Afrogitanopsis paguri ( Myers, 1974) ; Aoridae , with two species, Globosolembos excavatus ( Myers, 1975) and Grandidierella propodentata Moore, 1986 ; Oedicerotidae , with one species, Oediceroides wolffi Barnard, 1961 ; and Maeridae with one species, Quadrivisio bengalensis Stebbing, 1907 ( Horton et al. 2019). Floresorchestia mkomani Bichang’a & Hou, sp. nov. is the first Floresorchestia species recorded from Kenya. So far, amphipods published from Kenya and East Africa are marine species collected from the coastal region; neither terrestrial nor freshwater species have been published. To ensure a clear exemplification of the amphipod diversity in Kenya, East Africa and the African continent, more research is recommended.