Gibbosaverruca weijiai, Gan & Zhang & Wang, 2021

Gan, Zhibin, Zhang, Dongsheng, Li, Xinzheng & Wang, Chunsheng, 2021, Gibbosaverruca weijiai, a new verrucid (Crustacea, Thoracica) species from the Weijia Guyot deep-sea seamount in the West Pacific, European Journal of Taxonomy 739 (1), pp. 158-167 : 160-164

Gibbosaverruca weijiai sp. nov.

urn:lsid:zoobank.org:act:C0F9728C-1D03-4E52-BBE4-053C9586095D

Figs 1–4 ; Table 1

Diagnosis

All plates with prominent growth lines. External surface of rostrum with four ridges, uppermost largest, upper margin of rostrum sloping down to base of movable scutum, faint ridge between them. Movable tergum with three articular ridges, axial ridge strongly prominent, intermediate ridge widest. Movable scutum with three articular ridges, axial ridge thin, second ridge prominent, wider than axial ridge. Cirrus I and cirrus II with anterior rami no more than half length of posterior rami. Intermediate segments of cirrus VI with three pairs of setae on anterior margin. Caudal appendage very long, more than five times as long as protopodite.

Etymology

The new species is named after its type locality, Weijia Guyot, the West Pacific.

Material examined

Holotype WEST PACIFIC • measurements BD = 10.29 mm; roof deck of Weijia Guyot ; 156°41′15.72″ E, 12°47′22.20″ N; depth 1935 m; 21 Sep. 2017; crews of ROV Haima leg.; Stn MCROV06; Dayang 41B cruise; attached to sponge remains; GenBank: MW033972 (COI), MW033931 (16S rRNA); SRSIO17090313 .

Paratype WEST PACIFIC • 6 specimens, measurements BD = 7.82–10.36 mm; same collection data as for holotype; attached to sponge remains; SRSIO17090314 • 3 specimens, measurements BD = 8.05– 9.12 mm; roof deck of Weijia Guyot ; 156°17′13.56″ E, 12°22′37.92″ N; depth 1995 m; 22 Sep. 2017; crews of ROV Haima leg.; Stn MCROV02; Dayang 41B cruise; attached to sponge remains; SRSIO17090314 .

Description

Large-sized verrucid species. Shell white, growth lines prominent on all plates. Apices of rostrum and carina projecting well beyond margins of fixed tergum and fixed scutum ( Fig. 1A–C ). Rostrum and carina interlocking by four articular ridges ( Fig. 1A ), with narrow grooves between them on rostrocarinal articulation. Rostrum lower but longer than carina; anterior surface with four ridges, uppermost largest, as wide as following three ridges combined, lowest ridge faint; upper margin of rostrum sloping down to base of movable scutum, faint ridge between them terminating at end of axial ridge of carina. Carina with four articular ridges, first two similar in width, larger than following two; lowest ridge feebly developed.

Fixed tergum ( Fig. 1B, D ) higher than fixed scutum, axial ridge prominent, narrow, both sides with welldeveloped alar-like projections; apex flexed towards fixed scutum. Axial ridge of fixed scutum ( Fig. 1B, E ) wide, about three times width of fixed tergum; alar-like process directed toward rostrum, wide, about two times width of radius-like process, directed toward fixed tergum; apex straight.

Movable tergum ( Fig. 1A, F ) quadrangular, with three articular ridges; axial ridge prominent, narrow groove between it and intermediate ridge; intermediate ridge very wide, triangular, about three times width of axial ridge; broad groove between intermediate ridge and upper ridge; upper ridge thin, submarginal; internal surface smooth. Movable scutum ( Fig. 1A, G ) triangular, smaller than movable tergum; three articular ridges, axial ridge narrow, low, intermediate ridge largest, prominent, upper ridge short, sub-marginal; area between intermediate ridge and upper ridge smooth, without growth line; internal surface smooth.

Labrum ( Fig. 2A ) with line of bifid or trifid teeth. Palp ( Fig. 2B ) narrow, with simple setae on terminal and inner margin. Mandible ( Fig. 2C ) with three teeth, first larger than following two; inferior angle acute, superior border armed with series of spinules. Cutting edge of maxillule ( Fig. 2D ) inflected; upper angle with large spine and some cuspidate setae; lower region projecting, furnished with cuspidate setae. Anterior margin of maxilla ( Fig. 2E ) with small notch, upper and anterior margins covered by long setae.

Soft body ( Fig. 3 ) without filamentary appendage. Cirrus I separated from, and shorter, sturdier than cirri II–VI ( Fig. 3B ), coxopodite inflated; anterior ramus slightly shorter than half length of posterior ramus; both rami with wide basal segments tapering distally. Cirrus II ( Fig. 3C ) with anterior ramus slightly shorter than half length of posterior ramus. Cirri III–VI ( Fig. 3D–G ) with rami subequal; intermediate segments of cirrus VI with two pairs of long setae and one pair of short setae on anterior margin. Caudal appendage (Fig. G) very long, more than five times length of protopodite, with more than 50 segments. Number of segments of cirri I–VI and caudal appendage are presented in Table 1 . Penis ( Fig. 3H ) robust, tapering, surface with annular wrinkles. Eggs ( Fig. 3I ) globular, encompassed by transparent film capsule.

Habitat and distribution

Roof deck of Weijia Guyot, depth 1935–1995 m, attached to sponge remains ( Fig. 4 ). Currently only known from the type locality, Weijia Guyot.

Figures

Fig. 1. Gibbosaverruca weijiai sp. nov., holotype, SRSIO17090313. A. Opercular plates. B. Fixed tergum and scutum. C. From above. D. Fixed tergum. E. Fixed scutum. F. Movable tergum. G. Movable scutum.

Fig. 2. Gibbosaverruca weijiai sp. nov., holotype, SRSIO17090313. A. Inner edge of labrum. B. Palp. C. Mandible. D. Maxillule. E. Maxilla.

Fig. 3. Gibbosaverruca weijiaisp. nov., holotype, SRSIO17090313. A. Soft body.B. Cirrus I.C. Cirrus II. D. Cirrus III. E. Cirrus IV. F. Cirrus V. G. Cirrus VI. H. Penis. I. Eggs.

Fig. 4. In situ figures of Gibbosaverruca weijiai sp. nov. (red arrows).

Tables

Table 1. Number of segments on cirri I–VI and caudal appendage of the holotype of Gibbosaverruca weijiai sp. nov.

	I	II	Cirri III IV		V	VI	Caudal appendage
left	18/29	12/32	27/31	36/40	41/45	48/49	51
right	18/30	13/31	29/32	35/38	43/45	47/50	50