Stammericaris galichai, Cottarelli & Bruno, 2025

Stammericaris galichai View in CoL sp. nov.

( Figures 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

ZooBank: urn:lsid:zoobank.org:act:A2C3396F-113B-4C20-86B5-FD94F7C80DA6

Type locality. Sibuyan Island , Romblon Province, Cantingas River , hyporheic habitat on the right bank; approximate coordinates 12°19'33.80" N, 122°34' 38.50" E, 26 m a.s.l. GoogleMaps

Type material. Holotype: dissected male mounted on two slides labelled: “ Stammericaris galichai holotype: male, Sibuyan , Philippines, 28/VIII/1998 slide 1” ( MZUF 705 View Materials ) and “ Stammericaris galichai holotype: male, Sibuyan, Philippines, 28/VIII/1998 slide 2” ( MZUF 706 View Materials ) GoogleMaps . Paratypes: 1 male, dissected and mounted on one slide labelled: “ Stammericaris galichai paratype: male, Sibuyan , Philippines, 28/VIII/1998 ” ( MZUF 707 View Materials ) ; 4 males, undissected and mounted each on one slide labelled: “ Stammericaris galichai paratype: male, Sibuyan , Philippines, 28/VIII/1998 ” ( MZUF 708 View Materials , 709 View Materials , 710 View Materials , 711 View Materials ) ; 4 females; undissected and mounted each on one slide labelled: “ Stammericaris galichai paratype: female, Sibuyan , Philippines, 28/VIII/1998 ” ( MZUF 712 View Materials , 713 View Materials , 714 View Materials , 715 View Materials ) ; 2 females, dissected and mounted each on one slide labelled: “ Stammericaris galichai paratype: female, Sibuyan , Philippines, 28/VIII/1998 ” ( MZUF 716 View Materials , 717 View Materials ) . All material collected by Vezio Cottarelli.

Diagnosis. Male: antennule eight-segmented, of the “pocket-knife” type sensu Schminke (2010), seventh segment with tapering apical tip; cephalothorax with elliptical dorsal integumental window. Urosomites 2–5 each with dorsal elliptical integumental window; anal operculum well-developed, with rounded distal free margin reaching distal margin of anal somite, with transversal row of spinules ventrally; caudal rami shorter than anal somite; inner margin of P1 basis with hook; P2 enp as long as 3/4 of the corresponding exp-1, with few apical spinules and distal seta; P3 robust and slightly curved, with two groups of spinules on distal half of outer margin of exp-1; apophysis (i.e., ancestral distal segment) with constriction at midlength and distal half with membranous edge; thumb shorter than apophysis and characteristically curved. P4 endopod small and of peculiar shape, with small, triangular inner tip and single distal pinnate outgrowth; P4 basis ornamented with two spinules of different lengths, the one closer to the enp shortest, with a trilobed apex. P5 a trapezoidal plate with four distal setae. Female: cephalothorax with elliptical integumental window dorsally, urosomites 2–4 each with elliptical integumental window dorsally, anal operculum and caudal rami as in male, inner margin of P1 basis with long thin seta; P2 endopod with spinules apically and seta as in male; P3 endopod a pointed segment about 1/2 the length of the corresponding exp-1; P4 endopod about 2/3 the length of the corresponding exp-1, ending in spiniform seta with spinules around insertion. P5 quadrangular, narrower and more elongated than in male, armature as in male but setae lengths differ.

Etymology. The new species is dedicated to Rodne Rodiño Galicha, Filipino environmentalist and human rights activist, born in Sibuyan Island, in recognition of its involvement in biodiversity conservation and natural resources conservation. The specific epithet is a singular masculine noun in the genitive case.

Description. Adult male. Body unpigmented, nauplius eye absent. Total body length, measured from tip of rostrum to posterior margin of caudal rami (excluding caudal setae) from 344 to 580 μm, mean 483 μm (n = 6). Habitus ( Figure 1A View FIGURE 1 ) cylindrical and slender, without any demarcation between prosome and urosome; prosome/ urosome length ratio= 0.9. Free pedigerous somites without lateral or dorsal expansions, all connected by well-developed arthrodial membranes. Integument weakly sclerotized, without cuticular pits, ornamented with sensilla on all somites but preanal one. Sensillar pattern as in Figure 1A View FIGURE 1 . Cephalothorax with rounded dorsal integumental window ( Figure 1A View FIGURE 1 ), urosomites 2–5 with dorsal elliptical integumental window ( Figure 1A View FIGURE 1 ). Anal somite ( Figures 1A View FIGURE 1 , 2A View FIGURE 2 ) with pair of large dorsal sensilla at base of anal operculum, anal sinus wide open, with two diagonal rows of small proctodeal spines. Anal operculum ( Figure 2A View FIGURE 2 ) well-developed, with convex distal margin, transverse row of ventral spinules discernible through transparent operculum.

Caudal rami ( Figures 1A View FIGURE 1 , 2A View FIGURE 2 ). Diverging, approximately cylindrical, tapering distally, shorter than anal somite, anal somite/caudal ramus length ratio = 1.5; caudal ramus length/ width ratio = 2.18. Anterolateral accessory seta (I) shorter than anterolateral seta (II), posterolateral seta (III) short, all setae inserted together distally at 3/4 the length of caudal ramus; outer terminal seta (IV) long and pinnate (seta/caudal rami length ratio= 1.4), inserted subapically; inner terminal seta (V) without fracture plane; terminal accessory seta (VI) short (seta/caudal ramus length ratio= 0.9) and bare; dorsal seta (VII) bare, articulated, inserted distally at 3/4 length of the caudal ramus.

Rostrum (arrowed in figure 2B). Small, not demarcated at base, almost reaching distal margin of first antennulary segment, ornamented with two dorsal sensilla.

A1 ( Figure 2B View FIGURE 2 ). Prehensile, eight-segmented; seventh segment sickle-shaped, folded back onto the fifth segment, with eighth segment pointing medially, i.e., pocket-knife type sensu Schminke (2010). First segment short and bare; second segment longest, with five setae, one of which unipinnate; third segment with four distal bare setae of similar lengths; fourth segment reduced to small bare sclerite (indicated with an asterisk in figure 2B); fifth segment enlarged with inner triangular pointed expansion, distal tubercle with one basal short seta, two long subequal distal setae and large apical aesthetasc reaching past the distal margin of eighth segment; sixth segment bare, small and cylindrical, partially fused to previous one; seventh segment bare, sickle-shaped, with distal anterior corner protruding as curved apophysis ending in tip; eighth segment with seven setae and apical acrothek represented by one seta and slender long aesthetasc basally fused. Armature formula: 1-[0], 2-[1 uniplumose + 4 bare], 3-[4 bare], 4-[1 bare], 5-[2 bare +(1+ ae)], 6-[0], 7-[0], 8-[7 bare + (1 bare + ae)].

A2 ( Figure 2C View FIGURE 2 ). Coxa unarmed; allobasis with one abexopodal transverse row of spinules. Exp represented by small segment partially merged with allobasis, with bipinnate apical seta. Enp bearing along inner margin from proximal to distal: seven spinules of different lengths (four short, three long), two unipinnate spines of subequal lengths inserted at about 2/3 of margin; apically: two geniculate, two spiniform, and one transformed setae of different lengths, the transformed seta proximally smooth, medially serrate, and distally smooth. Two long and thin spinules along the outer margin, near the insertions of apical transformed seta.

Mandible ( Figure 2D View FIGURE 2 ). Coxal gnathobase with lateral pinnate short seta, cutting edge with two large and three small apical teeth. Palp one-segmented, with two distal setae of subequal lengths.

Maxillule ( Figure 2E View FIGURE 2 ). Praecoxal arthrite with three apical curved robust spines apically denticled, one lateral curved seta. Coxal endite long, with apical pinnate seta. Basis cylindrical, with two distal bipinnate setae of subequal lengths. Endopod and exopod absent (fused to basis without trace).

Maxilla ( Figure 2F View FIGURE 2 ). Syncoxa with two endites, proximal endite short, with one seta; distal endite cylindrical, armed apically with two subequal thin bare setae and one transformed, leaf-like pinnate seta; proximal endopodal segment drawn into apical unipinnate claw; vestige of distal endopod represented by two long setae of different lengths.

Maxilliped ( Figure 2G View FIGURE 2 ). Prehensile; syncoxa small and unarmed; basis slim and elongate, unarmed; endopod represented by distally unipinnate claw.

P1 ( Figures 2H View FIGURE 2 ). Intercoxal sclerite smooth and small; coxa bare. Basis large, armed with single slender seta and row of four spinules on outer margin, and lamellar, long inner hook with rounded tip near enp insertion. Exp three-segmented, slightly shorter than enp; exp-1 with unipinnate spine on outer distal corner; exp-2 shortest and unarmed; exp-3 with two apical geniculate setae, bipinnate in the distal half, and one unipinnate apical and one unipinnate subapical spines. Enp two-segmented; enp-1 as long as first two segments of corresponding exp combined, with spinules along outer margin; enp-2 shorter and thinner than enp-1, with one spinule at 2/3 of inner margin and two spinules along outer margin; apical margin with long geniculate unipinnate seta and shorter unipinnate spiniform seta.

P2 ( Figure 2I View FIGURE 2 ). Intercoxal sclerite quadrangular and smooth, with concave distal margin. Coxa with spinular row. Basis unarmed, with row of four spinules and small pore on outer margin. Exp robust, three-segmented, exp-1 longest, slightly curved inwards, with transversal rows of spinules at 1/3 and 2/3 of outer margin, and two short longitudinal spinules proximal to strong distolateral unipinnate spine. Exp-2 unarmed, with distal row of spinules; exp-3 short, with inner hyaline frill and distal row of spinules, armed with subapical outer unipinnate spiniform seta, one apical seta and one apical spine, both unipinnate. Enp one-segmented, slightly shorter than corresponding exp-1, cylindrical, with bare subapical seta about as long as segment, and five apical spinules.

P3 ( Figures 2J View FIGURE 2 , 3A View FIGURE 3 ). Intercoxal sclerite narrow and long, trapezoidal, unornamented, with concave distal margin. Coxa with spinular row. Basis robust, with basal pore on the dorsal surface, and long, slender, smooth outer seta and row of long spinules obliquely inserted along outer distal margin; row of small chitinous denticles along inner margin; enp reduced to short and thin seta. Exp-1 slender distally, two rows of four and eight spinules of similar length along outer margin in the second 1/2 of segment; exp-2 fused with exp-1, without ornamentation, prolonged into long finger-like apophysis, slightly bent inwards, with constriction at midlength, and distal half with membranous edges, ending with rounded tip. Distal thumb short, inwardly bent, long, approximately half as long as apophysis.

P4 ( Figures 3B, C View FIGURE 3 ). Intercoxal sclerite smaller than in P1-P3, with concave, smooth distal margin. Coxa with spinular row. Basis with anterior pore, armed with slender seta on outer margin; ornamented with row of spinules on distal outer margin and two spinules on inner margin, one of which long and inwardly-curved, one small and with apex consisting of three small lobes. Exp three-segmented, first segment strongest, second shortest; exp-1 armed with outer distal unipinnate spine and inner hyaline frill; with transversal rows of three spinules at 1/3 and 2/3 of outer margin and two spinules below insertion of spiniform seta, and spinular row along distal margin. Exp-2 unarmed, with row of spinules along outer distal margin extending to the inner distal corner; exp-3 armed with outer unipinnate spine and long apical bipinnate seta, spine about 1/3 the length of seta; ornamentation represented by row of apical spinules, row of spinules along distal outer corner, and inner hyaline frill. Enp one-segmented, slightly longer than 1/2 the length of the corresponding exp-1, represented by a plate curved inwards with pinnate tip and with one small, pointed outgrowth.

P5 ( Figure 3D View FIGURE 3 ). Pair of P5 not fused to intercoxal sclerite; represented by two trapezoidal cuticular plates with long basipodal seta. Armature on free distal margin, from inner to outer: three bare setae of which outermost short, innermost very long, middle one shortest.

P6 ( Figure 3D View FIGURE 3 ). Vestigial, fused into simple cuticular asymmetrical oval plate, unornamented and unarmed.

Adult female. Habitus ( Figure 1B View FIGURE 1 ) cylindrical and slender, without any demarcation between prosome and urosome. Body length, excluding caudal setae, from 300 to 542 μm, mean 468 μm (n = 6). Free pedigerous somites without any lateral or dorsal expansions, all connected by well-developed arthrodial membranes. Cephalothorax and urosomites 2–4 with dorsal elliptical integumental window of different sizes, largest one on genital double somite. Ornamentation of cephalothorax, somites, pigmentation, and lack of nauplius eye as in male, except genital and first urosomites fused into genital double-somite. Prosome/urosome length ratio= 1.0. Genital double-somite ( Figure 3E View FIGURE 3 ) without any trace of subdivision, with three ventral pores proximal and two ventral pores distal to genital field, and, two spinular rows distal from the two pores. Genital field ( Figure 3E View FIGURE 3 ) occupying anterior ventral third of genital double-somite; copulatory pore located medially at proximal third of genital double-somite, not covered by fused vestigial P6.

Anal operculum and anal sinus ( Figure 3F View FIGURE 3 ) as in male.

Caudal rami ( Figures 1B View FIGURE 1 , 3F View FIGURE 3 ). Shape, ornamentation and armature similar to those of male but rami proportionally longer, length/width ratio= 2.27.

Mouthparts, rostrum, A2 as in male.

A1 ( Figure 3G View FIGURE 3 ). Seven-segmented, aesthetasc on fourth segment as long as in male but proportionally thinner, reaching beyond seventh segment. First segment bare, second segment longest. Apical acrothek represented by one seta and slender aesthetasc basally fused. Armature formula: 1-[0], 2-[1 pinnate + 4 bare], 3-[4 bare], 4-[2 bare + ae], 5-[0], 6-[0], 7-[7 bare + (1 bare + ae)].

P1 ( Figure 4A View FIGURE 4 ). Intercoxal sclerite and coxa as in male. Basis as in male, but with thin and long inner seta instead than lamellar hook and pore; exp and enp similar to those of male.

P2 ( Figure 4B View FIGURE 4 ). Intercoxal sclerite, coxa, basis and exp as in male. Enp similar in shape to that of male, but apical seta smaller and thinner.

P3 ( Figure 4C View FIGURE 4 ). Intercoxal sclerite small, trapezoidal, with concave margin, bare. Coxa with spinular row. Basis armed with single seta, with pore and outer spinular row; exp two-segmented: exp-1 slightly longer and larger than exp-2, with distal curved unipinnate spine and two subdistal spinules, transversal spinular row at 1/3 of outer margin, hyaline frill on inner distal corner. Exp-2 with subapical outer unipinnate spine and longer apical bipinnate seta, subdistal outer spinule, apical spinular row and hyaline frill on inner distal corner. Enp represented by pointed and apically bipinnate segment, about 1/2 the length of the corresponding exp-1.

P4 ( Figure 4D View FIGURE 4 ). Intercoxal sclerite much narrower than in male, coxa as in male, basis as in male but without strong spinules on inner margin. Exp-1 as long as exp-3, exp-2 shortest; exp-1 with distolateral curved unipinnate spine and two transversal rows of spinules at 1/3 and 2/3 of outer margin, with distal spinular row and inner hyaline frill on distal corner. Exp-2 with distal spinular row; exp-3 with apical outer unipinnate spine and longer apical bipinnate seta, with distal spinule on outer margin, with apical spinular row, and inner hyaline frill on distal corner. Enp represented by thin claviform segment about 2/3 the length of the corresponding exp-1, ending in spiniform seta with spinules around insertion.

P5 ( Figure 4E View FIGURE 4 ). Pair of P5 not fused to intercoxal sclerite, represented by rectangular plates; narrower and more elongated than in male, armature as in male but the three innermost setae are of subequal lengths (i.e., two are longer and one is shorter than in male).

P6 ( Figure 3E View FIGURE 3 ). Two vestigial rectangular cuticular plates, not covering gonopore, unornamented and unarmed.

Variability. The exp-1 of the left P 3 in the male holotype has a distal row of eight spinules along the outer margin, and a row of nine spinules on the right P3 ( Figure 2J View FIGURE 2 ), in all the paratypes, the row consists of eight spinules on both pereiopods.