Grandidierella pawaiensis, Ali-Eimran & Lee & Azman, 2020

Ali-Eimran, Alip, Lee, Yen-ling & Azman, B. A. Rahim, 2020, Two new species of Grandidierella (Amphipoda, Corophiida, Aoridea) from Singapore, European Journal of Taxonomy 683, pp. 1-28: 4-15

publication ID

https://doi.org/10.5852/ejt.2020.683

publication LSID

lsid:zoobank.org:pub:F6D7ED9D-EF2E-4B94-AC48-45BA442CD043

persistent identifier

http://treatment.plazi.org/id/03DBAD42-2C11-B11B-FDC3-FCB3FB38B56E

treatment provided by

Valdenar

scientific name

Grandidierella pawaiensis
status

sp. nov.

Grandidierella pawaiensis   sp. nov.

urn:lsid:zoobank.org:act:F43BC745-2E46-4FB7-A993-FF242683C420

Figs 2–10 View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig

Etymology

This species is named after the type locality, Pulau Pawai, Singapore.

Material examined

Holotype

SINGAPORE • ♂ (bl 4.25 mm); Pulau Pawai ; 01º11.336ʹ N, 103º43.372ʹ E; 25 Aug. 2012; Wong Pei San Helen, Lee Yen-ling, Ria Tan, Toh Chay Hoon, Tay Ywee Chieh and Chen Chia Xin leg.; shallow water muddy bottom; ZRC 2018.0493 View Materials . GoogleMaps  

Paratypes

SINGAPORE • 1 ♀ (bl 3.85 mm); same collection data as for holotype; ZRC 2018.0494 View Materials GoogleMaps   1 ♂, 4 ♀♀, 1 juv.; same collection data as for holotype; ZRC 2018.0495 View Materials GoogleMaps   .

Type locality

Pulau Pawai, Singapore.

Description (based on the holotype ♂, ZRC 2018.0493)

BODY. Subcylindrical.

HEAD. Eyes present and well developed, set just posterior to margin of lateral lobe. Epimeral plate 3 about 1.4 times as long as 1 or 2. Head as deep as long, longer than pereonite 1; anteroventral margin moderately excavate, corner sharp.

ANTENNA 1 ( Fig. 3A View Fig 1 View Fig ). Peduncular articles 1–3 with ratio of 4:5:2; article 1 margins slightly convex with clump of slender setae near ventrodistal corner; article 2 slender, dorsal and ventral margins lined with slender setae; article 3 short, accessory flagellum present, uniarticulate, apically acute, half the length of flagellar article 1 with long slender apical setae; flagellum with at least 11 articles, distal margin of each article possessing short slender setae.

ANTENNA 2 ( Fig. 3A View Fig 2 View Fig ). Shorter and more robust than 1; peduncular articles combined length twice as long as flagellum; peduncular articles 3–5 with length in ratio 2:5:5; peduncular article 1 subquadrate, ventrodistal corner with long slender and 1 robust setae; article 2 ventral margin with short to long slender setae; article 3 slender, margins with slender setae; flagellum with 8 articles, distal margin of each fringed with slender setae, articles 6–8 with robust setae on ventrodistal margin, article 8 distally tapering.

UPPER LIP ( Fig. 4 View Fig UL). Broader than long, margin covered in short fine setae, distal margin prepubescent.

LOWER LIP ( Fig. 4 View Fig LL). Outer lobe entire margin covered in fine setae, medial margins prepubescent, distomedial corner with arborescent setae, distal margin possessing one plumose apical setae; mandibular lobe blunt, distally possessing short setae.

MANDIBLES ( Fig. 4 View Fig MD). Well developed, subtriangular; incisors each with 4 teeth; lacinia mobilis on left mandible with 4 teeth, right mandible with 2 teeth; spinal row armed with 6 processes; molar process well developed, rounded; palp triarticulate, article 1 shortest with article 3 longest; article 2 laterodistal margin slightly expanded, article 3 linguiform, apically rounded, lateral margin with long slender setae, left mandible apical and comb setae plumose, right mandible apical setae plumose, comb setae slender.

MAXILLA 1 ( Fig. 4 View Fig MX 1). Inner lobe vestigial; outer lobe distally truncate with 8 apical denticulate setae, proximolateral margin with fine setae; palp biarticulate; article 1 0.3 times as long as article 2; article 2 linguiform, distally rounded with 6 apical robust setae and 4 subapical setae, distolateral margin with 3 slender setae.

MAXILLA 2 ( Fig. 4 View Fig MX 2). Inner lobe subequal in length to outer lobe; inner lobe medial and lateral margins slightly convex, deep face covered in short setae, medial margin possessing long plumose setae; outer lobe lateral and medial margins straight, slightly distally expanded, lateral margin with short setae, distal end rounded with mixture of long slender and plumose setae.

MAXILLIPED ( Fig. 4 View Fig MXP). Inner lobe distally truncate, extending slightly beyond article 1 of palp, lateral margin with fine setae, medioproximal margin with long robust setae, mediodistal margin with 8–10 slender setae and 4 apically oblique processes; outer lobe almost reaching end of article 2 of palp, apically rounded with long robust setae, lateral margin convex and with fine setae, medial margin straight with robust setae and submarginal slender setae; palp 4-articulate, article 2 medial margin with long slender setae, article 3 distal margin covered in long slender setae with 1–2 serrate setae, article 4 subtriangular ending in a stout spine.

GNATHOPOD 1 ( Fig. 3G View Fig 1 View Fig ). Enlarged, more robust than 2, carpochelate; coxa small, anterodistally unproduced; basis posteriorly expanded, ventrodistal corner with slender setae; ischium subquadrate, ventrodistal corner with slender setae; merus not anterodistally produced, sparsely setaceous along distal margin; carpus enlarged, twice as long as propodus; dorsal margin convex, ventral margin straight, entire margin with slender setae, proximoventral corner with apically acute process, inner midface possessing apically acute process, anteroventral corner with 2 processes forming a broad excavate sinus; propodus posterodistal margin slightly expanded, fringed with slender setae; dactylus less than half length of propodus with notch ¾ of the way up ventral margin.

GNATHOPOD 2 ( Fig. 3G View Fig 2 View Fig ). Smaller than 1, subchelate; coxa subquadrate; basis distally expanded, anterodistal margin without flange, anterior margin crenulate; ischium subquadrate; merus with long setae on distal margin; carpus obovate, longer than propodus, dorsal margin moderately setose with long slender setae midway up margin, ventral margin with slender setae mid-margin; propodus dorsal and ventral margins parallel, dorsal margin with long slender setae, ventral margin with shorter slender setae, palm serrulate with a row of sub-marginal robust setae; dactylus curved, half the length of propodus, ventral margin doubly serrate.

PEREOPOD 3–4 ( Fig. 5P View Fig 3–P View Fig 4 View Fig ). Coxae subquadrate; basis slightly expanded; ischium subquadrate; merus distally expanded, dorsodistal margin with a pair of long robust setae, dorsal and ventral margins sparsely setaceous; carpus subovate; propodus elongate, longer than carpus, dorsal and ventral margins sparsely setaceous; dactylus falcate.

PEREOPOD 5 ( Fig. 5P5 View Fig ). Shortest; coxa posteriorly expanded into a tapering apically blunt process; basis with robust setae along anterior margin; ischium subquadrate; merus anterior margin with slender setae, anterodistal corner with a pair of long robust setae, posterodistal corner with 1 robust setae; carpus anterior margin with 3 robust setae, posterior margin with 3 short robust setae; propodus slender, with 4

short to long robust setae along anterior margin and 4 short robust setae along posterior margin; dactylus falcate.

PEREOPOD 6–7 ( Fig. 5P View Fig 6–P View Fig 7 View Fig ). Pereopod 6 shorter than 7; coxa small, anterodistally expanded into a tapering apically blunt process; basis posterior margin with plumose setae, anterior margin possessing short robust setae; ischium subquadrate; merus slightly expanded posterodistally, posterior margin with 3 long slender setae, anterior margin with short setae; carpus slender, anterior margin with short slender setae, posterior margin with 1–4 robust setae, posterodistal corner with long robust setae; propodus slender, ventrodistal corner possessing long slender setae; dactylus falcate.

UROPOD 1 ( Fig. 6U View Fig 1 View Fig ). Biramous, peduncle longer than rami, inner and outer rami subequal in length; peduncle lateral margin with 5 robust setae, medial margin with 4 robust setae, interramal spine present and shorter than peduncle; outer ramus with 3 robust setae on outer margin, apice with 4 robust setae.

UROPOD 2 ( Fig. 6U View Fig 2 View Fig ). Biramous, peduncle subequal in length to inner ramus, outer ramus longer than inner ramus; peduncle lateral and medial margins with 2 robust setae; outer ramus lateral margin with 3 robust setae, medial margin with 2 robust setae, apice with 5 robust setae; inner ramus with 4 apical setae.

UROPOD 3 ( Fig. 6U View Fig 3 View Fig ). Uniramous, ramus 3 times longer than peduncle; peduncle broader than long, outer lobe covered in short fine setae; ramus long, medial margin with 3 long serrate setae, lateral margin with 2 long serrate setae, distal end with 1 long apical setae and 3 long subapical serrate setae.

TELSON ( Fig. 6T View Fig ). Rhomboidal, broader than long, apically truncate, superior face with 4 short setae, distal margin with short fine setae, distolateral margins with long robust setae.

Female (dimorphic characters; based on the paratype ♀, ZRC 2018.0494)

GNATHOPOD 1 ( Fig. 7G View Fig 1 View Fig ). Subchelate, smaller than male; merus distal margin with one serrate setae; carpus ventrally expanded, with row of serrate setae on ventral margin; propodus subequal in length to carpus, obovate, palm serrate; dactylus about 0.75 times as long as propodus, palm serrate, defined by strong posterodistal spine; dactylus ventral margin doubly serrate.

GNATHOPOD 2 ( Fig. 7G View Fig 2 View Fig ). Basis anterior margin straight; carpus ventrally expanded with long serrate setae. Additional illustrations ( Figs 8–10 View Fig View Fig View Fig ) are also provided for future reference.

Remarks

Grandidierella pawaiensis   sp. nov. is closely similar to G. bispinosa   . However, the new species possesses a mixture of features that differ from the specimens collected from the Bismarck Archipelago ( Schellenberg 1938), the Moluccas ( Ledoyer 1979) and Fiji ( Myers 1981). Differences between specimens are mainly seen on gnathopods 1 and 2. For gnathopod 1, the dorsal margin of the carpus is more dorsally rounded, similar to the specimens collected from the Moluccas and Fiji. There is also the absence of 2 denticles on the ventromedial margin of the carpus as seen in Myers’ specimen. The anterior margin of gnathopod 2 is distinctly more crenulate in the present material.